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Lab Manual 2015 - John A. Goree

1. ct Decoder Driver and 7 Segment LED Display 7447 Forewarning this circuit is not hard but it requires hooking up more wires than most thus it might take more time Displays are popular output devices LEDs are brighter while LCDs consume far less power Both types of displays require a decoder driver to convert decode from BCD input and to drive the display LED displays have 8 leads for the 7 LEDs The displays and their corresponding driver IC s come in two varieties common anode and common cathode Ordinarily when using LEDs one uses a series resistor of about 150 O to limit the current Leave the BCD counter hooked up as it was at the end of part 4 above with a switch for the input and the 4 BCD outputs indicated by 4 LEDs 124 Ifthe part number is visible on the 7 segment display check to see if it differs from the LSD322X XX specified here In that case you will need to check the pin diagram for your display this can be done by searching the internet for the part number and looking for a data sheet Connect the BCD outputs of the BCD counter to the BCD inputs of the 7447 Connect the 7447 to the 7 segment LED display as shown e Note 1 pin configurations for LED displays is not standardized Pins are shown here for the SENIOR SEA3210 your display might have a different model number but the same pins This display has an additional LED fo
2. OUTPUT 32 Fig 2 A Adjust the oscilloscope settings to the following settings hereafter referred to as the original settings Vertical mode BOTH and ALT CH1 Volts Div 1 Volt use 1X indicator on dial input coupling DC CH2 same as CH1 INVERT switch set to the out position horizontal mode A time base A sec div 0 2 ms VAR HOLDOFF NORM A TRIGGER P P AUTO LEVEL turn to about the middle SLOPE out A amp B INT CH1 A SOURCE EXT A EXT COUPLING DC Adjust the function generator settings to produce a sine wave with a frequency of about 100 Hz with DC offset turned OFF Learn the various vertical modes Try various settings of the vertical mode switches and see the display Use the BOTH mode on the vertical mode Compare ALT and CHOP You may need to adjust the beam intensity on the scope Change time base to 5 us observing the display Again compare ALT and CHOP You may be able to see the chopping of the signals in the chop mode Do you understand the difference between ALT and CHOP Learn how to use X Y mode First return the oscilloscope to the original settings Then set the time base to X Y 33 Vary the CH1 and CH2 volts div and see how the display changes Make a Lissajous figure Connect a 8 V transformer to CH1 and a sine wave from the function generator to CH2 Adjust the frequency to multiples of 60 Hz while watching the display
3. Turn on the power You will now cause the outputs to go to a desired known condition by clearing the shift register Record the values when you turned it on Then Connect the CLR pin 1 to LO by connecting a wire directly to GND The other chip inputs don t matter when you are clearing Verify that momentarily bringing CLR to LO causes all outputs QA through QD to be set to LO if they weren t already so Now set CLR to HI by connecting it to 5V through a current limiting resistor 10k is typical This will prevent CLR from changing the values of the outputs during the remainder of the experiment 118 b Serial shift sequence 195 Truth table for serial shift INPUTS at tn OUTPUTS at tN41 J K QA QB Qc QD L L QAN QBN H H H QAN QBN L H QAN QAN H L QAN QAN QBN QCN Now set SH LD to HI to allow serial shifting You should have the serial inputs J and K connected together First set J and K to LO by connecting their external input resistor to GND Now clock the register several times by pressing the data switch for CLK Determine whether any outputs change their state Second set J and K to HI by connecting their external input resistor to 5 Now clock the register once Determine whether QA changes state and if so whether it did this on a rising or trailing clock edge Third set J and K back to LO Then clock the register several times
4. Lab 3 Diodes Power Supplies Zeners and SCRs REFERENCE Horowitz and Hill Sections 1 25 1 30 rectification filtering regulation Sections 6 11 6 14 power supply parts Sections 6 16 3 terminal regulator INTRODUCTION In this lab we examine the properties of diodes and their applications for power supplies and signals Diode rectification in half wave and full wave bridge circuits Filtering in power supply circuits 3 terminal voltage regulator Zener diode and its use as a voltage regulator Diode clamp circuit Silicon controlled rectifier SCR Note the instructor probably will choose not to do all of the above Professor Goree usually skips the SCR We will also build our measurement skills learning to use a digital oscilloscope 38 EQUIPMENT Lab supplies Digital Oscilloscope Function generator Multimeter handheld model only to protect the more expensive Agilent 34410A do not use it for this lab Prototyping board Transformer center tapped 8 V Variac for 3 term regulator Resistor substitution box Potentiometer 50k for SCR circuit SCR for SCR circuit 0 30 V dc power supply 6 V lamp for SCR circuit Test leads Scope probe BNC banana plug adapter Student kits Wire kit Power diodes 4 amp spares Signal diodes 2 1N914 or similar Zener diode 1 amp spares 5Vorl0V Resistors 91 2W 1k 56k 110k for SCR circuit Capacitors 0 47 uF 100 uF 2 1000 uF for SCR circui
5. a Coupling DC BW Limit OMH digital scope Volts Div Coarse counter Probe push button switch is 7 normally closed but open i TE goo when pushed CHT 200 M 100005 CHI f 2161 128 b De bounced switch The circuit shown below is called an SR flip flop or a cross coupled NAND latch Wire it up using a 7400 quad NAND gate chip Now add a switch with pull up resistors to make a data input as shown below Press the switch and observe that the counter counts only one clock because the switch is now de bounced 5V 10k counter 5 129 73 The 042 BCD to Decimal Decoder Chip Before wiring the circuit convert the following decimal numbers to BCD 0i Bs Wire the decoder chip with four inputs for BCD input Use the switches on your prototyping board to provide input as shown below BCD INPUTS binary 23 22 21 20 state DC B A IC pin 12 13 14 15 board SW1SW2 SW3 Sw4 A Apply the BCD input corresponding to 0 Touch a wire connected to an LED indicator to test the states of the 10 output pins Verify that the output pin corresponding to 0 is LO and the other outputs are HI Repeat with data inputs 1 and 8 130 Lab 10 Digital Meets Analog REFERENCE Horowitz and Hill Sections 8 20 one shot Section 5 14 555 timer Section 9 15 9 16 9 20 DAC amp ADC INTRODUCTION In this lab we will test
6. 175 only ZLEAR Q1 Q1 D1 D2 Q2 Q2 GND TL F 6557 Order Number 54175DMQB 54175FMQB DM54175J DM54175W or DM74175N CLEAR 151 Flip Flop 5V GND 115 a Basic operation Use Vec 5 V and GND to power this chip Connect CLR pin 1 to a breadboard switch set to HI Provide data to the D1 input pin 4 from a prototyping board switch by setting the D1 input to HIGH Clock the flop pin 9 with a momentary contact switch for example logic switch A on the prototyping board Setup LED indicators of the input D1 output Q1 pin 2 and its complement Qj pin 3 1 Verify that the D flop ignores information presented to its input before a rising edge on the clock and that it then shifts that value to the output Draw a timing diagram showing CLK D1 and Q1 ii Verify the Truth Table in the data sheet by copying the truth table the figure labeled Function Table above by placing a check mark by each entry that you test and verify Label the state on the timing diagram that corresponds to each entry in the truth table b Shift Register Leaving the first flip flop set up as it is apply its output Q1 to the D2 input of another flip flop and so on for four flip flops total as shown below Connect the four outputs Q1 through Q4 to LED indicators Set CLR to HI using a switch on the prototyping board Usea clock frequency of about 1 to 10 Hz or use a momentary
7. DC Current Gain 1 0 1 mAdoc Vcg 10 1 1 0 Vcg 10 Vdo 1 10 mAde Vcg 10 Ic 10 mAde Vcg 10 Vde TA 55 C 1 150 mAde Vcg 10 1 Ic 150 mAde Vcg 1 0 Vdc 500 mAde Vcg 10 1 Collector Emitter Saturation Voltage t 1 150 mAde lg 15 mAdc 1 500 mAde lg 50 mAdc Base Emitter Saturation Voltage 1 150 mAde lg 15 mAdc 1 500 mAde lg 50 mAdc 59 A BASIC FACT TO KNOW In electronics e Itis USUALLY OK to connect an output of a circuit to the inputs of two circuits e Itis NEVER OK to connect two outputs together Circuit 1 Circuit 2 Usually OK m NEVER Circuit 2 out OK 60 PRELAB 1 Identify all the formulas you will need in this Lab 2 In this lab we will use a method of measuring the input impedance Zin of a circuit This impedance will be purely resistive because the circuit will have no significant capacitance or inductance The scheme is to connect a large input resistor Ra in series with the circuit s input and measure the resulting decrease in the circuit s output You can think of RA and the circuit s input impedance as being like two resistors in series i e a voltage divider See the diagram below the circuit which has a gain Av is shown as a box with an input and an output a Derive a formula for Zin as a function of Ra Vosc Vou and the gain A b Wr
8. DC voltage Setthe function switch of the multimeter to DC volts with a scale commensurate with the voltages expected in the circuit To protect the meter from damage ALWAYS SELECT THE MAXIMUM VOLTAGE SCALE TO START WITH Then adjust the scale downward until a meaningful reading is obtained a Batteries in series Measure the individual voltages V1 and V2 of two 1 5 V batteries Then connect the batteries in series with forward polarity as shown in Fig 1 7 and measure the total voltage V meas Provide an uncertainty for this measurement based on the multimeter s specifications T 1 5V 1 5V battery battery _ multi meter 1 5V 15V 7 battery battery Figure 1 7 Figure 1 6 Two batteries connected in series with forward Board with two batteries polarity left and reverse right Reverse the polarity of one of the batteries and measure the total voltage V meas Provide an uncertainty for this measurement based on the multimeter s specifications Calculate the expected results V1 V2 and V cac V 1 V2 for forward and reverse polarity of the two batteries Note that these are calculated quantities not measured quantities so that their uncertainty must be calculated using propagation of errors Perform this uncertainty calculation yielding and 6 V carc Compare these expected results 8 Vcac and V caic SV catc to the corresponding
9. If output button is not lit there will be no waveform applied to the instrument s output ii operation with non symmetric power supply Agilent 33220A Function Generator Now connect the emitter return the resistor on the bottom of the figure to ground instead of 12 V Observe the display for several amplitudes of input Explain how the circuit functions more poorly 64 iii breakdown Look for bumps appearing at reverse bias This is called breakdown Measure the breakdown voltage i e the voltage at which breakdown first occurs Compare your result to the specification in a data sheet for the transistor Note the breakdown voltage specifications for the 2N3904 and the 2N4400 are identical so for this purpose you may use either data sheet iv voltage gain Connect the emitter return back to 12 V Add a blocking capacitor to the output as shown in Figure 4 6 Why don t we use a blocking capacitor on the input It s not necessary When the function generator feeds the base directly the DC bias of the base is held to that of the function generator which is near the middle of the transistor s operating region That s where we want it 12V in 10k 2N3904 0 1 uF oii R ES 33k 12 Figure 4 6 Adjust the input amplitude of the sine wave from the function generator so that the output looks like a good sine wave Measure the ac voltage gain v blocking capacitor test Use
10. Input impedance In the voltage mode the input impedance of a digital multimeter is usually high enough several that it has negligible effect on the circuit being measured Continuity check Many models allow you to check continuity emitting an audible beep so that you don t need to look at the meter while making the test AT Hooking up the meter Note that the meter is connected e in parallel to measure voltage or resistance e in series to measure current See the figures to see how this is done V Q Hz COM 20A i 19 Input jacks on a multimeter MAX X INPUT d vz 2s Hz 250 y 1000 UNFUSED 750V 10A L es cael MES SO ce Ohy LAN BV ig lle 200 2K VO COM ET o e AO 2 2707A DL HIT 2707 a Voltage V b Resistance 2 c Current A Multimeters The meter can measure voltage resistance and current Note two things e which connectors at the bottom are used e where the dial points your dial might look different from the one shown here but somewhere it will have 2 and A for measuring voltage resistance and current EF Figure 1 4 Using a multimeter shown by the Figure 1 3 Using a multimeter shown by the Figure 1 5 Using a multimeter shown by the circle with a V to measure voltage circle with a R to measure resistance circle with an to measure current
11. Recall the relationship of angular frequency o units s and the usual frequency f Hz Calculate the roll off frequency in Hz 1 2zRC that you expect for the low pass amp high pass filters using the nominal values for R and C as specified in the schematic diagrams Calculate the charging time RC in msec that you expect for the low pass filter circuit Find the formula for the frequency response curve for a high pass filter This formula will be an expression with the ratio Vout Vin on the left hand side of the equation and the right hand side will depend on f R and C Find or make a graph of this function Find the formula for the frequency response curve for a low pass filter Find or make a graph of this function 24 PROCEDURE Read Appendix A in Horowitz and Hill 2 Ed You will need to know oscilloscope terminology before you begin In this lab you will record a lot of data It is recommended that you record it in columns in your lab notebook with separate columns for the reading e g in mV the scale on the oscilloscope e g 100 mV per division the estimated error for each measurement 1 Measurement of Voltages a DC Voltages start adjust the oscilloscope settings to the following vertical mode CH1 CH1 Volts Div 1 Volt use 1x indicator on dial input coupling GND r CAL knob fully clockwise to click CH2 same as CH1 set INVERT switch to the out position horizontal
12. Reduce the input pulse width and verify that the output pulse width at the output of the one shot is unaffected by the pulse width at its input Setup for using external resistance parts c and d We will now use an external resistor for timing The RC time determines the pulse width The one shot has an internal timing resistor with a nominal value of Rint 2 refer to the data sheet to confirm this value You could use that internal resistor to time the pulse but you will instead use an external 10k resistor c d Replace the shorting wire between pin 9 the internal resistor and pin 14 with a 10 k external resistor Measure the pulse width and compare the theoretical value Rex C In 2 input replace the signal from pulse generator with the square wave signal from the 555 timer that you built in part 1 Verify that this combination works as a pulse generator Digital to Analog Conversion DACO808LCN or equivalent The DACOSOS is an easy to use 8 bit D to A converter DAC Wire up the DAC as shown in the figure Use wires to connect the inputs of the three most significant bits MSBs on pins 5 6 and 7 to the input switches on your prototyping board Connect the other five 138 inputs to LO by connecting pins 8 through 12 with wires directly to ground Connect a multimeter to the analog output pin 4 Make a table showing all eight possible combinations of the
13. 4 Digital ICs 74HCO00 and 74L S00 Quad NAND 74LS02 or 74HC02 Quad NOR 741 504 or 74HCO04 Hex inverter 74LS86 or 75HC86 XOR 7ALS151 8 Input Multiplexer 101 A BASIC FACT TO KNOW In electronics e Itis USUALLY OK to connect an output of a circuit to the inputs of two circuits e Itis NEVER OK to connect two outputs together A circuit s output attempts to establish the voltage on its wire A wire can have only one voltage If you connect two outputs to the same wire the voltage on that wire will be unpredictable m Usually OK Circuit 1 Circuit 3 NEVER OK Ei Students making this error in their final project will be penalized greatly PRELAB 1 Look at all the diagrams in this lab and verify that you are never asked to connect two outputs together although you are often asked to connect an output to multiple inputs 2 Thetwo input exclusive or XOR truth table with inputs A and B is Using the truth table for a NAND gate verify that the circuit in Fig 8 3 should have a truth table that is the same as XOR 3 Refer to a textbook e g Horowitz amp Hill 2 Ed p 495 for a description of a multiplexer Learn how the address bits are used to select which of several inputs is sent to the multiplexer s output 4 Whyisit not okay to connect the outputs of two chips together 103 PROCEDURE 0 Things to know About digital inputs In making tests you will need to conn
14. 90 rule might be adopted voltage Vr Vo Vr Vo 90 time 1 1 L risetime falltime 77 EQUIPMENT Lab supplies Digital Oscilloscope Pulse generator HP8013B DC power supply Prototyping board 10X probes 2 and a manual for this probe model Small screwdriver to adjust the 10X probe Student kits Wire kit Resistors 270 1k Light emitting diodes HLMP C115 obsolescent this LED chosen for its 30 nsec response Red diffused LED NPN Phototransistor Panasonic PNA 1801L 78 002020 NOTE 1 Unit mm 0 197 0 008 amp 7120 20 1 14 20 20 0 343 0 008 0 045 0 006 1 85 0 073 MAX Not soldered 2 0 max 0 70 0 028 MAX 15 0 1 0 5 80 20 20 0 228 x 0 008 9 190 0 015 NOTES 1 ALL DIMENSIONS ARE IN MILLIMETERS INCHES 1 Emitter 2 LEADS ARE MILD STEEL SOLDER DIPPED 2 Collector 3 AN EPOXY MENISCUS MAY EXTEND ABOUT 0 5 ee 0 020 in DOWN THE LEADS HLMP Cx15 and HLMP Cx23 LED HLMP C115 NPN Phototransistor PNA1801L Note the flat edge of rim Note emitter pin is longer indicates cathode 79 PRELAB 1 Identify all the formulas you will need in this Lab If a waveform ramps up gradually from a starting voltage to an ending voltage what percentage of its change is used when measuring the rise time 80 PROCEDURE 1 Adjust 10X probe compensation As you previously le
15. Don t worry if you are unable to make the figure stationary it is hard to make two independent Lissajous figure oscillators operate synchronously Learn about trigger levels First return the oscilloscope to the original settings and set the time scale to 0 2 ms Change the cables to the function generator as shown in Figure 2 4 Adjust the function generator to produce a sine wave of about kHz Vary the trigger level and the trigger slope Observe the results Do you understand why the display depends as it does on these settings Change the trigger mode from AUTO to NORM Adjust the trigger level and or the function generator amplitude until you see that the oscilloscope no longer triggers Then adjust them back so that they do trigger Do you understand why the display depends on these parameters in the NORM trigger mode Return the oscilloscope triggering to AUTO before proceeding 34 Learn to use the pulse generator Repeat the steps above using the delayed sweep but this time use the Pulse Generator instead of the Function Generator The purpose of this exercise is to learn about pulse generators and to further develop oscilloscope skills O For the output use the pulse generator s right most BNC connector Adjust the HP pulse generator so that it has the following settings OUTPUT Sliding switches RATE Hz PULSE PERIOD s Pulse period 20 ns 1 us TEXT 20n iu Am 10m 1 Pulse delay a
16. GND H high level L low level a XOR from 7486 Figure 8 3a b XOR using NAND only Figure 8 3b Seethe pin diagram above Write down a Truth Table and check off every state as you test it Draw the gates 5 Half Adder See Figure 8 4 Connect this circuit Write down a Truth Table and check off every state as you test it Draw the gates 109 6 151 Multiplexer A multiplexer is a switch It has multiple inputs and a single output The purpose of the multiplexer is to allow the user to determine which of the inputs should be connected to the output Dual In Line Package DATA INPUTS DATA SELECT OS r Irr rrrrx r Irrzr rrmx X L L L L H H H H I I r H High Level L Low Level X Don t Care D3 D2 01 00 Y W STROBE GND 00 01 07 the level of the respective D input DATA INPUTS OUTPUTS TL F Order Number 54LS151DMQB 54LS151FMQB 54LS151LMQB DM54LS151J DM54LS151W DM74LS151M or DM74LS151N Connect the 74LS151 as shown below DATA SELECTS OUTPUT binary 22 21 20 state C B A M IC pin 9 10 11 5 board SW1 52 SW3 LED1 Set the following pins on the 74LS151 to LO Strobe pin 7 All data inputs except D1 Multiplexing Predict by examining the truth table which combination of input states A B and C will result in an output Y that is HI or LO if D1 is HI Write your predictions in the form of a table with four col
17. Observe whether any data move from QA to QB etc and if so whether the move takes place on a rising or trailing clock edge c parallel load sequence Choose the input number 1010 by setting the data switch A to 1 data switch B 00 etc Load the input data by momentarily making SH LD LO Then clock the CLK input once Determine whether the input data for A is loaded to output QA etc on a rising or trailing clock edge d Serial shift sequence Do another serial shift sequence and watch the data you previously loaded in parallel shift serially Determine whether the outputs QA etc change state on a rising or trailing clock edge AII of your results for steps a through d above should be presented in a timing diagram like the example shown here Pay careful attention to lining things up vertically in your diagram Use a full page if needed 119 Example Timing Diagram for 195 shift register This is an example You should draw your own diagram showing your own results O 5 J SERIAL INPUTS K J 1 OO M M 4 Dou TEE a PARALLEL DATA 1 INPUTS 1 t t I D Wen EP E c c LU OUTPUTS es dl xem eee ee aD ESTEE Boer E p SERIAL SHIFT I SERIAL SHIFT 9 CLFAR LOAD a b
18. c d 3 The 161 Synchronous Binary Counter TA Note This circuit can be deleted if necessary This is a 4 bit binary counter with data inputs that can be preset i e programmed so that it begins counting from a desired number Binary counters contain JK flip flops Connect to pin 16 and GND to pin 8 Connect the inputs of 74L S161 to switches on the prototyping board and the outputs to LEDs as follows INPUTS OUTPUTS binary 23 22 21 20 23 22 21 20 state INp INC INg INA LOAD OD Qc QB Qa IC pin 6 5 4 9 11 12 13 14 board SWi SW2 SW3 SW4 SWA LED1 LED2 LED3 LED4 Connect pin 2 CLK to a 1 Hz clock on your prototyping board 120 Set the following pins on the 74LS161 to HI you may use data input switch on your prototyping board to accomplish this Enable P pin 7 Enable T pin 10 Clear pin 1 When LOAD pin 9 is LO the counter can be loaded with a binary number on data inputs IND INC INB INA When it is HI clock signals are counted Before using the circuit convert the decimal number 12 to binary Program the counter so that it will count from 12 Do this as follows With LOAD LO input the decimal number 12 on the input switches Then set LOAD to HI Now clock the CLK input and watch the chip count in binary from 0 to 15 Note that it will start at the value 12 that you programmed then count up to 15 then start over at O Draw a timing diagr
19. is 4 3 Substituting Vin Vin2 we find that the mode gain is R2 R4 Ry RAR which is zero if R3 R and R4 R2 So CMRR Ap Ac is perfect infinity if R3 R and R4 R2 However resistors actually have a tolerance of typically 596 and therefore the common mode gain will not actually be zero and the CMRR will not be infinity R2 R1 ini O in 2 O out R3 R4 Figure 7 6 Differential Amplifier Connect the circuit in Figure 7 6 using resistor values Rj R2 R3 R4 10 k 93 a Differencing Usethe setup with a sine wave and a dc signal set up that you used for the summing amp Verify that the output is the difference of the two inputs as predicted by Eq 4 2 by marking values at particularly significant times on the printout of the scope display b Differential mode gain Apply the sine wave to input 1 and connect input 2 to ground Measure AD Vout Vin Compare to the value predicted by Eq 4 3 using actual measured values for the resistors c Common mode gain Connect both inputs to the sine wave Measure AC Vout Vin Compare to the value predicted by Eq 4 4 using actual measured values for the resistors d CMRR Compute CMRR Ap AC 5 Integrator low pass filter The circuit in Figure 7 7 is an integrator which is also a low pass filter with a time constant Rj C Resistor
20. o The gain in dB of an amplifier with a gain of 0 1 o The voltage ratio that corresponds to 3 dB 87 PROCEDURE 0 Things to know non inverting input out inverting input Figure 7 1 Symbolic representation of an operational amplifier Anop amp ideally obeys the rules 1 The output voltage does whatever necessary to make the two inputs at the same voltage 2 The current drawn by the two inputs is zero Also an external feedback network must be provided that connects the output to the inverting input this provides negative feedback The pin configuration for an 8 pin DIP op amp is shown in Figure 7 2 as viewed from the top offset null connected inverting input LA non inverting input out V offset null op amp mini DIP package in most applications the offset null is not connected Figure 7 2 Op amp pin configuration 88 Note that an op amp is an active component that must be powered to work Most models need a bi polar power supply On a schematic diagram the power supply connections to an op amp are often not shown Connect the two terminals V and V to a 15 V power supply or 12 V on your prototyping board The prototyping board A prototyping board is made especially for DIP dual inline package ICs Many models have built in power supplies that you may use Use wires to connect the outputs of the 12 V power supply and ground three wires in all to a couple of narro
21. 2 M 50035 H1 wn 3 CHI Time per division horizontal Volt per division vertical Press the AUTOSET button to see the display of a square wave Push the CH2 MENU button twice to see how this turns the display for that channel off and on The two channels are distinguished by their color 43 To see their effect adjust these knobs VOLTS DIV SEC DIV VERTICAL POSITION HORIZONTAL E cm POSITION Look for the arrow at the top that indicates the Coupling trigger time and the arrow at the right that indicates zero OL voltage BW Limit Off Push the CH1 MENU button to see the display Toggle the M Probe setting so that it indicates the same setting as on your E probe 1X not 10X or 100X You must always check this Volts Div before using the scope to avoid X10 errors in your voltage measurements Probe Push the TRIG MENU button and view the menu Sometimes in this course you will be asked to use EXT TRIG which you can accomplish with the digital oscilloscope by toggling Invert Source to the Ext setting At other times you might wish to use CH1 as the Source 2811 Build your triggering skills First choose AUTO trigger with the source specified as the same channel 1 or 2 as your probe While viewing the square wave from the probe adjust the trigger level knob up and down while watching the display Observe that when the trigger level is adj
22. CMOS is more common than TTL because it has a lower power dissipation Nevertheless your instructor may prefer TTL for this course because TTL chips unlike CMOS are immune to damage by static electricity Static electricity can destroy CMOS chips To avoid damage e store unused chips properly in special plastic tubes or special plastic bags e before handling a CMOS chip ground yourself by touching a ground such as the metal cover plate on an electrical power outlet on wall About the light emitting diode LED In building digital circuits you will often use an LED as an indicator of the state HI or LO Series resistors e ALWAYS USE A RESISTOR IN SERIES WITH THE LED e Typically 220 Q e The series resistor is needed to avoid destroying the LED The LED is a diode and when it is on it has very little resistance If you connected an LED directly between a source and either ground or it would try to pass an infinite amount of current which will burn up the LED 220 105 About buffers for the LED A buffer is often needed to drive an LED The outputs of many gates and circuits cannot source enough current to drive an LED directly this is when you must provide a buffer The buffer is a digital version of a follower its output is at the same voltage as the input but is capable of driving more current while sinking very little at its input Your prototyping board has LEDs that are LOGIC
23. ICs used to interface digital and analog circuits The first is a popular chip for making oscillators the 555 Next is the monostable multivibrator One Shot which can produce a jitter free trigger signal from a rising or falling analog input Finally we will set up an digital to analog converter DAC and an analog to digital converter ADC EQUIPMENT Lab supplies Digital Oscilloscope Function generator Agilent Digital Multimeter Pulse generator DC power supply Prototyping board Temperature sensor LM35DZ TA stored in cabinet Student kits Wire kit Capacitors 0 1 uF 3 0 01 uF 0 001 uF Resistor 3k 2 5 1k 2 10k 4 Integrated circuits 74121 one shot LM555 or 7555 timer DACOS08 8 Bit Digital to Analog Converter ADCO0804 8 Bit Analog to Digital Converter Copyright 2015 John A Goree Edited by John Goree 5 Jan 2015 The terms pulse generator and square wave generator refer to different things A square wave generator is usually a bipolar oscillator The waveform swings from positive to negative voltages Sometimes it has a feature to add an arbitrary DC offset to the output A pulse generator is usually not bipolar and there is usually no DC offset adjustment A pulse swings between zero and either a positive voltage as in the case of logic circuits or a negative voltage Pulse generators are used to clock digital circuits 5 V Ur Ehe EET square wave 5 V F TILL TL pu
24. INDICATORS already wired so that you can use them as o oo oO digital indicators Le 1334 without a buffer one part next part of digital of digital circuit circuit with a buffer one part s next part of digital of digital circuit circuit 106 1 04 Hex inverter Use the 5V power supply for Vcc Install the 04 hex inverter on the prototyping board Examining the pin diagram choose any of the six inverters Connect its input to a data switch and its output to a Logic Indicator LED Verify that a HIGH on the input will cause the corresponding LED to be dark LOW Verify that a LOW on the input will cause the corresponding LED to be bright HIGH Write the truth table 1 e function table for the inverter Try using an LED in series with a 220 Q resistor instead of the LED built into the prototyping board to display the state of the gate s output 2 Quad 2 input NAND 74HC00 CMOS 74LS00 TTL 5 7400 PACKAGE SN74LS00 SN74S800 D OR N PACKAGE TOP VIEW FUNCTION TABLE each gate INPUTS OUTPUT e v H H L L x H X L H 107 This chip has four NAND gates each with two inputs hence the name Quad 2 input NAND Look up the pin configuration in a data sheet The output pins are 3 6 8 and 11 Connect Vcc to 5 V If you are using a prototyping board with built in input switches use these for the inputs
25. Use the prototyping board Use the 5 Volt power supply built into the prototyping board to supply Vin Figure 1 10 Voltage Divider a without load Measure Vj and Vout for R1 3 3 k and R2 1 6 k Then repeat with R1 1 6 k and R2 3 3 k Compare Vout Vin to the predicted values b with load Connect a 1 load resistor across the output Determine how much V is reduced loaded reporting the reduction of Voy as of the unloaded measurement of Vout Using the rules for parallel resistances compare to theory Note that while a voltage divider is easy to build it is a poor voltage source Its output is not stiff It is easily loaded 9 Learn how to use the prototyping board no response needed for lab report The prototyping board Prototyping boards are rows of connectors wired together behind a plastic face Things you can stick into the little holes of prototyping boards include wire 22 gauge solid core is typical resistor leads 1 4 or 1 8 Watt is typical leads for transistors capacitors diodes etc 13 CLOCK LOGIC SWITCHES y z kHz A LOGIC INDICATORS L4 Le L3 La CLK GND CLK DATA SWITCHES swi1 swe SW3 swa POWER SUPPLY Prototyping Board eee wee es wee ee ees ICs the hole spacing is made for DIP dual inline package chips Putan alligator clip connector on
26. a homework problem Build the circuit shown in Figure 7 5 Choose 10 k 10k R1 in 1 in2 O out Figure 7 5 Summing Amplifier Usea4 Volt P P sine wave for input 1 Use a 5 V dc voltage from a power supply your prototyping board is ok for input 2 Connect the oscilloscope using DC input coupling to monitor input 1 and the output Confirm that the output is minus the sum of the inputs Sketch or print the waveforms and mark values at the following phases of the sine wave peak trough and zero Also present calculations showing that the output is approximately equal to the expected value of the sum of the inputs do this for three cases corresponding to the three phases peak trough and zero 4 Difference Amp The circuit in Figure 7 6 is a differential amplifier Recall that the common mode rejection ratio is defined as CMRR differential mode gain common mode gain i e CMRR Ap AC Using Op amp rules 1 and 2 as described in Horowitz amp Hill 2 Ed one can derive that 92 V R2 v v R4 m ou inl in2 4 1 Note that if R2 R3 R4 then the output is a simple difference Vout Vin2 Vin 4 2 More generally we can find expressions that are valid even if the resistor values are not all exactly identical which of course they won t be in practice due to resistor tolerances Substituting Vin Vin2 we find that the differential mode gain
27. and use the built in LEDs to display the outputs At first use the CMOS chip a NAND Figure 8 1a b Inverter with NAND Figure 8 1b c AND Figure 8 1c d OR Figure 8 1d e NOR Figure 8 1e f Mystery NAND circuit Figure 8 1f Seethe pin diagram above Write down a Truth Table for each configuration listed above and check off every state as you test it Draw the gates Finally replace the CMOS chip with the TTL chip and verify that the chip works the same i e that the truth table for a is the same as for the CMOS chip For the remaining exercises you may use either TTL or CMOS 3 Quad2 Input NOR 74LS02 or 74HC02 SN7402 N PACKAGE SN74LSO2 SN74S02 D OR N PACKAGE TOP VIEW 1Y 1A 1B 2Y 2A 28 GND FUNCTION TABLE each gate 35 It is a useful exercise to look up the pin diagram in the data sheet which can be found either in a Data Book or on a manufacturer s website This skill is necessary when you design a circuit yourself 108 a NOR Figure 8 2a b Inverter with NOR Figure 8 2b c OR Figure 8 2c d AND Figure 8 2d See the pin diagram above Write down a Truth Table and check off every state as you test it Draw the gates 4 74LS86 or 74HC86 517486 N PACKAGE SN74LS86A SN74886 D OR N PACKAGE TOP VIEW FUNCTION TABLE 1A INPUTS OUTPUT 1B lA Bl y L L L H H 2B E 2Y H L H H 1 H
28. application its output swings from one rail to the other depending on which of the two inputs is more positive Note The student will need software to make graphs EQUIPMENT Lab supplies Prototyping board Digital Oscilloscope Function generator Digital Multimeter Resistor substitution box Photocell NSL 4522 from cabinet not included in parts kit Lab supplies Wire kit Op amp 2 LF411CN or equivalent 8 pin DIP Comparator LM311N Resistors 1 k 2 4 7 k 10k 4 22k 100 k 5 M Capacitor 0 01 uF 50 pF Potentiometer approx 50 k okay to re use part from Lab 3 kit 86 PRELAB 1 Identify all the formulas you will need in this Lab In this lab you will use decibels or dB This is a dimensionless ratio in logarithmic form The formula is 20 logio IXI where X is the dimensionless ratio of two amplitudes For example X might be the gain A of an amplifier which is the ratio of the output and input amplitudes If the gain A of an amplifier is 100 you can also say that the amplifier has a gain of 40 dB Note that negative values correspond to a ratio of less than unity for example an amplifier with a gain of 0 01 has a gain of 40 dB You can compute a voltage ratio by taking the exponent of 10 for example the voltage ratio corresponding to a gain of 15 dB is 10057 5 623 As your prelab exercise calculate the following o The gain in dB of an amplifier with a gain of 10 000
29. capacitor Use the oscilloscope to observe the waveforms at the output and at pin TH Measure the duty cycle of the output waveform Duty cycle fraction of time the output voltage is high Specify your answer in percent e g 37 5 5 Measure the frequency two ways 13 e Using the digital oscilloscope s measure function e Agilent multimeter Compare to the predicted value fosc 11107 RA 2 lt In a research lab and in the Project at the end of this course when you make measurement it is best to choose an instrument that yields a known error For the measurement of frequency the Agilent multimeter has the advantage that you can easily determine the error by referring to the manufacturer s specifications The Tektronix scope has manufacturer s specifications also but for frequency they are not easy to understand 135 c Replace Rp with a short circuit Describe the resulting waveform Explain your observation Leave this circuit hooked up You will use it with the one shot in the next part 555 Timer square wave oscillator 2 Monostable Multivibrator One Shot 74121 The output of a one shot is a digital pulse triggered by an analog waveform at its input Even if the input is noisy the one shot will produce a clean pulse The pulse has a width determined by an RC time and the pulse height is determined by the input voltage The pulse begi
30. common anode 7490 decade counter 74112 JK flip flop 74175 D flip flop 74161 4 Bit Synchronous Binary Counter 74195 4 Bit Shift Register Capacitors 0 1 uF Resistors 150 O 10 k 2 Seven Segment LED common anode LSD322X XX or LN513RA Copyright 2015 John A Goree Edited by John Goree 5 Jan 2015 PRELAB 1 Explain the difference between parallel and serial e what is meant by parallel input e what is meant by serial shift 2 What is the difference between common cathode and common anode for a seven segment display 3 Look up the pin diagram for the 142 BCD to decimal decoder chip To do this just do an internet search for the generic part number to find a datasheet You ll need to include a prefix of 74 74LS or 74HC they all have the same pin configuration 114 PROCEDURE es D Flip Flop 74HC175 or 74LS175 The D Flip Flop is the simplest but most important Flip Flop It simply saves at its output Q what it saw at its input D just before the most recent clocking edge The chip used below the 175 has four flip flops and they respond to a rising edge on the clock input Dual In Line Package Q4 CLOCK Function Table Each Flip Flop H High Level steady state L Low Level steady state X Don t Care T Transition from low to high level The level of Q before the indicated steady state input conditions were established
31. measured values V meas 6 V meas and Vf meas amp n both your notebook and lab report you must always draw a schematic of whatever you connect including components and any external instruments For this step the schematics should look like Fig 1 7 As you gain experience you will learn how to draw schematics without being shown an example to copy b Power supply A power supply is a voltage source powered by 110VAC You will use a bench power supply which has supplies an adjustable voltage A benchtop power supply typically has two knobs voltage and current The way it works is that only one knob will have an effect depending on two things the setting of the other knob and the load resistance For example if you turn the current knob up to its maximum value and if you use a large resistance for a load across the power supply outputs the voltage knob will be the one that has an effect while the current knob merely provides an upper limit to how high the current is allowed to go This will be how you will usually operate the power supply in this course An analog meter with a needle will have a measurement error due to your ability to read it Use your own judgment of what you think is a reasonable value for the error based on factors such as the width of the needle the spacing between tick marks and parallax due to viewing the meter with your head positioned at various angles Setth
32. science At the end of this course the student should be able to 1 design and build simple circuits of his or her own design 2 use electronic test amp measurement instruments such as oscilloscopes timers function generators etc in experimental research REFERENCE This manual is coordinated with the following textbook Horowitz and Hill The Art of Electronics 2nd Edition 1989 1990 Cambridge University Press A copy of this book is in the lab DATA SHEETS Data sheets for integrated circuits can be found online by searching for the part number They can also be found in books such as the Texas Instruments or National Instruments references for TTL CMOS and LINEAR circuits These books are on a shelf in the lab iii LAB NOTEBOOKS As a part of training to be a scientist students should maintain a personal notebook just as a research scientist does This lab notebook will not be graded but the student must have one and use it It must be bound with no loose pages Here is a guideline for lab notebooks a notebook should contain sufficient detail so that a year later the experiment could be duplicated exactly In the notebook the student should draw a schematic diagram for every circuit that is built a labelthis diagram with e part numbers e pin designations e output input designations a show the major connections to external power supplies etc list the instruments used by type and model a include in
33. the output impedance of the amplifier If a fixed current i passes through the effective resistance the voltage drop across it as given by v i R will be reduced by half if R is reduced by half 66 Set the resistor substitution box resistance to the largest possible value Then connect the resistor substitution box across the output of the amplifier to serve as a load resistance as shown in Figure 4 8 12V V cc in 10k 2N3904 SA Ae 01 uF 4 gt 3 3k RI 12 Figure 4 8 Adjust the input signal to obtain a good sine wave on the output Then reduce Rr until the peak to peak output signal falls by 1 2 Then Rr equals the output impedance of the circuit d Comparison Compare the measured input and output impedances by calculating their ratio Rout Rin Usually it is desirable for an amplifier to have a high input impedance and a low output impedance To what extent is that true here Transistor switch Transistors are used often as switches One application is cold switching where a remotely located mechanical switch which carries little current controls a larger current someplace else A transistor switch operates in the saturated mode when the switch is and in the cutoff mode when the switch is off It should not be operated in the normal or 67 linear mode where Ic hfe Ip See Appendix G in Horowitz amp Hill 2 Ed for more on saturatio
34. this list oscilloscope multimeters function generators etc record a table of all measurements a include units e g mV for inputs and outputs a record the scale e g 200 mV of the meter or oscilloscope a for digital circuits this table may be in the form of a truth table record error values for measurements that have an uncertainty list more than one measurement as an error check Q estimate the error bar PRELAB A spiral notebook is ok for this course Researchers use notebooks with sewn in pages In each lab you are given prelab questions These are intended to help you prepare for the lab You should write your response in this manual These questions are not handed in and they are not graded If you do not understand a prelab question be sure to ask your TA iv LAB REPORTS For each Lab students will individually prepare a lab report for grading This report is distinct from the notebook the notebook is not a substitute Reports should be organized as a brief introduction and then an experimental section that is organized according to the section number Preface brief introductory paragraph 30 words describing the report s theme Experiments REPEAT THE FOLLOWING FOR EACH SECTION Apparatus schematic diagram labeled with part numbers e g 1N914 diode pin designations on ICs output input terminals list of instruments used e g Tektronix 2235 oscilloscope Procedur
35. your oscilloscope with dc coupling to measure the dc bias of the output on each side of the output capacitor Confirm that the output capacitor is blocking a dc bias 65 Note the following procedures for measuring input and output impedances will be used again in later experiments b Input Impedance You will measure the input impedance Zin Because there is no significant capacitance or inductance at the input of this circuit we can write that Zin Rin See the discussion and diagram in the PRELAB Insert a large value resistor RA typically 1 MQ in series with the function generator on the input of the amplifier as shown in Figure 4 7 1 MQ 0 o to amplifier input Figure 4 7 Usethe oscilloscope with AC input coupling to measure the output signal with and without the large input resistor RA Calculate the input impedance Rin If you measured hfe earlier compare your result for Rip to the formula given in Horowitz amp Hill 2 Ed p 66 Rin hfe 1 RE c Output Impedance To measure an amplifier s output impedance you will connect a load resistor across the output Recall that when two resistances Rj Ro are connected in parallel the parallel resistance is Reff R1 R2 R1 R2 When the two resistances are identical Rj R2 R then Reff R 2 Now consider that a load resistance connected across the output of an amplifier is effectively a resistance in parallel with
36. 0 000 nF 1 uA 0 40 0 10 100 00 nF 10 pA 0 40 0 10 1 0000 uF 10 pA 0 40 0 10 10 000 uF 100 pA 0 40 0 10 viii Analog oscilloscope The display has about 8 boxes divisions in the vertical direction and 10 boxes horizontally It also has 5 small tick marks within each division You can usually measure a value to about 0 25 of a tick mark i e 0 05 divisions Example You use the oscilloscope on the 2 Volt div scale and your result is 5 3 Volt The error bar is 0 05 divisions so your final result is 5 3 0 1 Volt Propagation of Errors When two or more experimental measurements are combined into one by some mathematical operation such as a product P I V the two errors add in a non trivial way Example You measure 1 2 0 1 mA and V 2 5 0 3 V The error of P is computed using partial derivatives as dP D dP P oV V V2 di av 11 2 2 52 0 12 1 27 0 32 2 0 44 mW so the result you report for the measurement is P 3 00 0 44 mW In general For F F A B C the uncertainty F in terms of the uncertainties dA dB etc is given by dF gt A dA 2 dB Note that errors add through their squares In this lab course you are asked to use propagation of errors only twice both times in Lab 1 in order to develop this skill These two instances are indicated in Lab 1 with a footnote Otherwise to save time do no
37. 01 0100 binary 100111010 For this chip outputs QA QB and Qp are the four bit BCD outputs Disconnect the pulse generator Useaswitch on your prototyping board SWA to apply a pulse input on pin 14 Connect QA pin 12 to the 5 input pin 1 for BCD counting It may already be connected this way from part c above By means of LED indicator lights you may use those built into the prototyping board test the levels of the D C B and A outputs pins 11 8 9 12 respectively after each pulse 1 counting Write a copy of Table 9 1 and check off each state 0 through 9 to confirm that the outputs D C B and A of the counter accumulate in a BCD counting cycle Note the output may at first indicate an invalid number such as 1011 when you first turn on the power If this happens just apply several pulse inputs until a new cycle begins 123 ii resetting ee Verify by copying the first two rows from the Mode selection table above and placing check marks by the entries as you test and verify them that setting both the reset inputs MR1 and MR2 to HI will zero the outputs at D C B and A of the decade counter To avoid wasting time do not take this circuit apart yet Leave this circuit wired up for use with the 7 segment display in the next part Table 9 1 decimal BCD Q UJ D 0 QOooompnmmnPn nmn oooo
38. Follower a Emitter Follower Operation Using the 12 Volt power supply that is built into your prototyping board wire up an NPN transistor as an emitter follower as shown in Figure 4 4 12V Veo 10k NA 2N3904 in out Re 3 3k 12V Figure 4 4 63 POWER SUPPLY Figure 4 5 Power supply on prototyping board left Connect these using wires to the strips sketched on the right for convenient use Note some boards have only on strip per side not two as shown here Hint On your prototyping board use wires to connect the outputs of the 12 V power supply and ground three wires in all as shown in the left of Figure 4 5 to a couple of strips that look like those shown on the right of Figure 4 5 Set up the Agilent 33220A function generator to produce a sine wave that is symmetric about zero volts turn off the offset Initially adjust it for f 1 kHz and P P amplitude 2 V Do not use the Burst or Sweep modes here Setup the oscilloscope to show a dual trace using DC input coupling with one channel showing in and the other showing out Besure the grounds of the oscilloscope function generator and prototyping board are connected i input and output waveforms Print the oscilloscope display and number your printout so that you can identify it in your report Repeat for an input amplitude that is much larger and much smaller Comment on any significant differences
39. PHYS 3850 Electronics Laboratory Manual John A Goree Department of Physics and Astronomy The University of Iowa Updated for Spring 2015 Copyright O 2015 John A Goree Edited by John Goree 5 Jan 2015 TABLE OF CONTENTS page Preface iii Lab Notebooks iv Lab Reports Symbols Used in this Manual vi Resistor Color Code vi Treatment of Experimental Errors vii To the Instructor ix Lab Weeks typical 1 DC Measurements 1 2 AC Measurements 1 5 3 Diode Power Supplies Zener SCR 1 2 4 Junction Transistor Part I 1 2 5 Junction Transistor Part II 0 5 6 Optoelectronics can be scheduled any time after Lab 4 0 4 du Operational Amplifier 1 5 8 Digital Gates 1 9 Flip Flops Shift Register Decade Counter Decoder LED Display 1 3 10 Digital Meets Analog 1 Project 4 An average student will require approximately 3 hours to complete a lab that is indicated as 1 week Some students will require more than 3 hours Lab grades will be weighted by the number of weeks shown when computing the lab component of the course grade ii PREFACE GOAL The purpose of the experiments described here is to acquaint the student with 1 analog amp digital devices 2 design of circuits 3 instruments amp procedures for electronic test amp measurement The aim is to teach a practical skill that the student can use in the course of his or her own experimental research projects in physics astronomy or another
40. R2 provides DC feedback for stable biasing since without it there would be feedback through the capacitor only and that would not provide any DC feedback Note if you observe a severe dc offset on the output of the circuit you may replace R2 with a 100k resistor 1 The output is Vout R C vi dt const 1 Adjust your function generator to produce a square wave which will be applied to the integrator circuit s input a Integration x Print waveforms for Vin and Vout at 1 kHz 94 b DC stability Remove the resistor R2 and see if anything unfortunate happens to the output waveform the effect might not occur or it might not be extreme Be sure to use DC coupling on your oscilloscope input c Frequency response the frequency while observing the input and output waveforms on the oscilloscope It is not necessary to record data for this step Discuss in one sentence how your observations are consistent with the description low pass filter R2 5MO C 0 01 uF 10k in O out Figure 7 7 Op Amp Integrator 6 Differentiator high pass filter TA Note If necessary this circuit can be deleted so that students have time for the comparator The configuration in Figure 7 8 with the main components and R2 is a differentiator Differentiators always have difficulty with high frequency noise so a low pass filter combination C2 and is added to reduce th
41. S TOLERANCES Silver 2 Gold 1 Black 0 none 20 Brown 1 silver 10 Red 2 gold 5 Orange 3 Yellow 4 abcd Green 5 Blue 6 Violet 7 Gray 8 White 9 abx 10 d as of 2001 Graphical Analysis was installed on PCs at this location Start Programs Vernier Software GA vi TREATMENT OF EXPERIMENTAL ERRORS Error does not mean a mistake It means an uncertainty In measuring any value the result is not just one number such as 5 3 Volts It is two numbers 5 3 0 1 Volts The second number is the experimental uncertainty or error bar It usually represents one standard deviation one sigma from the first value In making an analog measurement with a meter or an oscilloscope you should record not just the first number but the error as well To decide what value to assign to the error you must use some judgment Here are some tips Multimeters The manufacturer gives specifications for the precision for the multimeter The precision of a BK model 388 HD hand held multimeter is DCV 0 50 rdg 1 LSD ACV 1 25 rdg 4 LSD F 2 00 rdg 4 LSD ACA 1 50 rdg 3 LSD DCA 1 00 rdg 1 LSD Q 0 75 rdg 1 LSD Hz 1 00 rdg 3 LSD where rdg is the reading on the display and LSD is the least significant digit Example You measure a DC voltage and get 5 30 Volt 1 2 The uncertainty is given as 0 5 96 of the reading or 0 005 x 5 30 plus 1 x LSD where the LSD is 0 01 here So the uncer
42. This precaution will keep you from accidentally setting the resistor substitution box to zero resistance 54 ii Regulation Vary Rr beginning at 10 1 and stepping downward to 500 Note the load resistance above which the voltage stays approximately constant To what current does this correspond SCR Circuits optional depending on whether TA finds there is enough time in most years this part is skipped a DC Control RC Timer The circuit in Figure 3 8 switches on a voltage across the load after a delay The SCR switches on when the gate voltage G exceeds the cathode voltage C The gate voltage is developed across the capacitor C by the R C combination Short to remove all charge 1 Switching time Turn on the supply and determine the time for the voltage to be switched across the load ii Gate voltage Short again and repeat with each of the resistors in the time constant portion of the circuit Determine the gate voltage necessary for firing scope in CH1 scope in CH2 scope GND Figure 3 8 RC Timer 55 b AC Control Lamp Dimmer In the circuit in Figure 3 9 the R C combination acts as a phase shifter for the 60 Hz AC voltage As R is increased the phase is shifted from 0 to 90 With this circuit it is possible to control the output half wave from completely on to completely off Use the input from the transformer secon
43. am for the counting showing CLK and outputs QA QB QC QD 4 Decade Counter 7490 Referring to the diagrams below from the data sheet we see that the 90 has four internal Flip Flops The first one is not internally connected to the others while the other three are cascaded to form a divide by 5 synchronous counter LOGIC DIAGRAM LS90 E TORIA _ MODE SELECTION RESET SET INPUTS OUTPUTS Qo Q4 Q2 Q3 LL L L ak L t H L L H Count Count Count Count L X H L X X L H HIGH Voltage Level O PIN NUMBERS NC NO INTERNAL CONNECTION LS LOW Voliega Level Vcc PINS X Don t Care GND PIN 10 121 Connect the 90 as follows note the unusual power supply pin assignments 1 5 10 input 2 GND 3 GND 4 NC 5 5 V 6 GND 7 GND 8 Qc 9 QB 10 GND 11 5 output 12 2 output 13 NC 14 2input Foran input in parts a to c use the pulse generator to produce square pulses between 0 and 5 V at 5 kHz If you have difficulties below in getting a desirable signal from the outputs of the chip check the input waveform it sometimes helps to set the pulse generator s INT LOAD switch to the in position or reduce the pulse height below 5 V Setup a scope for dual trace operation to show the pulse input from the pulse generator and an output either pin 11 or 12 depending on what you are measuring of the 90 Trigger the scope internally usi
44. arned in Lab 3 a 10X passive prove attenuates voltage by a factor of 10 so that an oscilloscope measures one tenth the original voltage It is preferred over a 1X probe for high frequencies gt 1 MHz and therefore it is used whenever one needs to measure fast rise times lt a few microseconds Due to variations in oscilloscope input capacitances it is necessary to adjust a compensation trimmer on a 210X probe after moving it from one oscilloscope to another Adjust the compensation on both of your 10X probes This requires a small screwdriver Verify that the probe s switch is in the 10X position Follow the steps of the 10X probe manual p 3 of the manual for the P2200 200 MHz Tektronix probe This procedure requires a square wave input use the two metal loop connectors labeled Probe Comp on the oscilloscope One connector is for the probe tip and the other for the probe s ground connector Set up the digital oscilloscope so that both the CH1 and CH2 menus are set for Probe 10X DC coupling BW Limit off Invert off 81 Identify the phototransistor and LED they look alike but the LED is much larger and the bumps on its leads are nearer its lens Identify the two leads of the phototransistor collector and emitter and the LED cathode and anode Discuss in one or two sentences why the phototransistor has no base lead Set up the pulser as shown in the photo except that you should use th
45. arying electrical signals You will measure DC and AC voltages Frequency Phase Time constant of an RC circuit Amplitude and phase shift responses of low pass and high pass RC filters EQUIPMENT Lab supplies Analog Oscilloscope Tektronix 2235 or equivalent Function generator BK 4017 Pulse generator HP 8013B DC power supply Multimeter handheld Multimeter Agilent 34410A 8 V transformer BNC cables BNC TEE BNC banana adapter wooden board with binding posts use computer to plot graphs print graph paper at end of this manual to draw waveforms Student kits Resistors 5k Capacitors 0 003 uF Copyright O 2015 John A Goree BNC TEE BNC banana adapter BNC cable Edited by John Goree 5 Jan 2015 ABOUT ANALOG OSCILLOSCOPES The heart of an analog oscilloscope is its cathode ray tube see Figure 2 1a An electron gun produces a beam of electrons that strikes the screen making a visible spot The beam is deflected by two pairs of deflection plates A sawtooth time base voltage is supplied internally to the horizontal deflection plates to sweep the beam linearly with time across the screen horizontally The voltage to be observed is supplied to the vertical deflection plates The result is a picture of the signal voltage versus time Electron Gun Vertical Input Signal Horizontal Input Time Base Sawtooth Figure 2 1 17 ABOUT TRIGGERING Trig
46. ate When using a switch to input data to a logic circuit bounce is unfortunate because it looks like real data that is changing several times circuit intended to provide an output waveforms voltage vs input to a digital circuit time from switch 5 what the switch does what it looks like to a digital input out what you really want a Bouncy switch Use a momentary contact switch not the switch built into your prototyping board it is already de bounced Use the multimeter to check continuity to see which two terminals to use on the switch so that it is normally open and closed only when you push Connect the simple SPDT input data switch shown below so that the switch is normally connected to LO This SPDT switch may be either push button as shown or toggle 127 Adjust a digital oscilloscope with DC coupling and approximately 100 or 250 usec div Observe the waveform of the output of the switch adjusting the trigger and timebase so that you can see any bounce as in the photo below Apply the output to the clock input of a counter circuit you may use any of the counter circuits you built above Press the switch and watch an LED indicator of the counter output Does the counter count more than one clock due to bounce Observe and print the waveform produced by the switch Use a digital storage oscilloscope 5V Tek Nu E Read M Pos 144 0ns CH1 es FYTTTTTYTTTETTTTTYT
47. b 1 with the crude current source 70 Lab 5 Junction Transistor Part II REFERENCE Horowitz and Hill Sections 2 07 2 12 common emitter amp INTRODUCTION We continue the bipolar transistor experiments begun in the preceding experiment In the common emitter amplifier experiment you will learn techniques and terminology that are valuable not only in building circuits but also in the use of commercially made amplifiers EQUIPMENT Lab supplies Prototyping board Oscilloscope Function generator Agilent 33220A Digital multimeter Agilent 34410A Resistor substitution box Student kits Wire kit NPN Silicon Transistor 1 233904 Resistors 220 1 k 6 8 k 12k 82 k for CE amp Capacitors 0 1 uF 10 uF electrolytic for CE amp Copyright 2015 John A Goree Edited by John Goree 5 Jan 2015 PRELAB Identify all the formulas you will need in this Lab Compute the intrinsic emitter resistance re for a transistor with a collector current of Ic 2 mA Your answer should have units of Ohms Referring to your text or lecture notes describe the undesirable circuit behavior that can result if the dc bias of the common emitter amplifier s output is not centered between the two power supply voltages 72 PROCEDURE Common Emitter Amplifier The common emitter amplifier shown below is based on Figure 2 37 in Horowitz amp Hill 2 Ed with changes to accommodate 12 V instead of 15 V in t
48. color If the LED is aligned properly you will see half of a big red dot on the paper with the center of the red dot located at the center of the phototransistor s lens 82 LED facing the phototransistor at a distance of about 1 cm LED illuminates a spot of this size on the paper shown here with dashed lines Phototransistor facing the LED Paper blocking half the phototransistor s lens so that you can see where the light is Obtain an oscilloscope display similar to what is shown in the screenshot adjusting the horizontal position as necessary Check that that the signal disappears when you insert a piece of paper between the LED and the phototransistor to fully block the light Note The photo shown here is best viewed in color to see the light from the LED Press the measure button on the scope and set it to measure Peak Peak and rise time as shown in the screen shot below Without disturbing the LED or phototransistor determine the criterion used by the oscilloscope to measure the rise time Do this by measuring the waveform yourself Measure three voltages Vo before the rise V after the rise is complete and V at the time indicated by the scope as the measured rise time Hint Remember the skills you learned when using the analog scope manual measurements are easiest if you make use of the major division lines on the scope display Adjust the horizontal position or trigger delay so that the pu
49. core wires to stick into prototyping board Alligator clips for multimeter test leads Board with three terminals 2 A fuses may be needed by TA Student kits Wire kit Resistors 100 560 1 k 1 8 k 3 3 k 50k TA note Check batteries and fuses in all multimeters before use Check prototyping boards to verify that their power supplies work banana plug Multimeter PRELAB Note this page is best viewed in color 1 Identify all the formulas you will need in this Lab 2 Describe one mistake that can damage a multimeter for each of the following measurements A voltage B resistance C current 3 State whether propagation of errors can be used to find the uncertainty of A aquantity measured directly using a multimeter B acalculated quantity based on more than one measurement C both of the above 4 Use the resistor color code chart to determine the value of a four band resistor with the colors brown black brown gold Multiplier wee i 4 E 47 000 Ohms TIEN or Multiplier AT K n Tolerance 2 Red 5 Gold 1096 Silver PROCEDURE Familiarization with equipment The digital multimeter The hand held digital multimeter is used widely to make electrical measurements of Voltage dc amp ac current dc amp ac resistance continuity other quantities such as frequency depending on your meter s features
50. ctly in Celsius Centigrade e Output is linear 10 0 mV C scale factor 0 5 C accuracy at 25 C General Description from the National Semiconductor datasheet e The LM35 series are precision integrated circuit temperature sensors whose output voltage is linearly proportional to the Celsius Centigrade temperature The LM35 thus has an advantage over linear temperature sensors calibrated in Kelvin as the user is not required to subtract a large constant voltage from its output to obtain convenient Centigrade scaling e The LM35 does not require any external calibration or trimming to provide typical accuracies of 1 4 C at room temperature and 3 4 C over a full 55 to 150 C temperature rang e Low cost is assured by trimming and calibration at the wafer level e The LM35 s low output impedance linear output and precise inherent calibration make interfacing to readout or control circuitry especially easy It can be used with single power supplies or with plus minus supplies As it draws only 60 pA from its supply it has very low self heating less than 0 1 C in still air Use the LM35 Precision Centigrade Temperature Sensor chip which has a sensitivity 10 mV per degree C The diagrams below are from the datasheet for the LM35DZ Use a power supply voltage of Vs 5V Caution before turning power on check polarity of the LM35 pins otherwise you will burn it up Connect the se
51. d off laser diodes have the advantage of producing a narrower spectrum of wavelengths helps overcome the dispersive effects of glass where different wavelengths travel at different speeds There are many kinds of light sensors In this lab you will test a photo transistor Other light sensors include e photodiodes faster time response but less sensitive e photo darlingtons these are like a phototransistor but include an additional transistor to provide additional gain at the expense of a slower time response e photomultiplier tubes a vacuum tube with a very fast time response Measurement skills you will learn in this lab include e using a digital oscilloscope to measure a high speed pulse e using a 10X probe which is useful because it has a higher bandwidth and faster time response than a 1X probe Copyright 2015 John A Goree Edited by John Goree 5 Jan 2015 Overshoot A pulsed waveform does not transition instantly between two levels Instead it follows a curve which asymptotically approaches the final level In some cases a waveform will overshoot the final level Voltage overshoot Square wave with overshoot Rise time and fall time The speed of switching between the two levels is characterized by a rise time and fall time These are often measured as the time interval between the 10 and 9046 voltage levels as shown below Sometimes however a criterion different from the 10
52. d twiddle the offset up and down You should see a vertical deflection of the trace Now change the oscilloscope coupling to AC and twiddle the offset voltage slowly You should see no change Explain the difference between AC and DC coupling Through what additional component inside the oscilloscope does the signal pass when using AC coupling 2 Measurement of Frequency Use the same set up as above Use a digital multimeter to measure the frequency connecting the multimeter to the function generator s SYNC output which might be labeled TTL depending on the model of the function generator Determine the frequency from the measured time per cycle Repeat for five frequencies in total over the entire Sync output of range of the function generator function generator Make a table to compare the frequency measurements made with the oscilloscope to those with the digital multimeter Include columns for the measurement uncertainty error values Which is more accurate the meter or the oscilloscope Asa practice never trust the frequency and voltage readings shown on a function generator Always make external measurements of the frequency and voltage For the remainder of this experiment use the multimeter for your frequency measurements 27 3 Time Constant of an Circuit The output voltage of an RC filter is V t Vmax 1 exp C t RC for charging Vit Vmax exp t RC for dischargi
53. dary as a reference signal for the oscilloscope Observe the phase shifted wave across C and the output wave across Explain why the lamp dims 5V Lamps 1 or 2 110 VAC iE Je Figure 3 9 56 Lab 4 Junction Transistor Part I REFERENCE Horowitz and Hill Section 2 01 2 12 Appendix G Appendix K data sheet for 2N4400 INTRODUCTION Junction transistors are either NPN or PNP with the symbols in Figure 4 1 Small signal type transistors come in various pin configurations An NPN in a TO 92 package is shown in Figure 4 2 In the junction transistor a small base current few uA controls a much larger Emitter Collector current 1 0 mA You will demonstrate the transistor in three common applications e Emitter Follower Common Collector Amplifier Transistor Switch Current Source Better performing than the one in Lab 1 This experiment will also improve your skills at wiring circuits and using test amp measurement instruments Copyright 2015 John A Goree Edited by John Goree 5 Jan 2015 EQUIPMENT Lab supplies Prototyping board Digital Oscilloscope Function Generator Agilent 33220A Pulse Generator HP 8013B Digital Multimeter Agilent 34410A Light bulb typically 47 0 15 A 6 3 V with wires SPST switch Resistor substitution box Student kits Wire kit NPN Silicon Transistor 2N4400 or 2N2222 as a substitute for switching 2N3904 for amplif
54. digital input states on the three most significant bits Then measure the analog output Vout for all of these states Vec 12V 45V DAC0808 analog out Veg 12V 139 Analog to Digital Converter Note This circuit requires 23 wires to hook it up on your prototyping board An ADC is often used to interface digital circuits or computers to the real world especially to acquire data Your digital multimeter for example has an ADC Among other things an ADC contains comparators and voltage reference levels The incoming analog signal is compared to the voltage reference levels to determine which is closest A corresponding digital output bit is then set to TRUE An ADC is rated by the number of bits and the maximum clock speed We will use the ADC 0804 an inexpensive ADC that is contained on one chip It digitizes eight bits at a clock speed up to 1 4 MHz It can be clocked by an external pulse source or by connecting a resistor and capacitor to make a simple relaxation oscillator analogous to the way the 555 works we will do the latter here The ADC 0804 has two analog inputs for differential voltage measurement For convenience in testing this ADC we will ground one of the differential inputs pin 7 and to the other one pin 6 we shall apply a simple dc voltage One way of doing this is to use a voltage divider as a voltage source with an op amp voltage follower to assure a low output impedanc
55. djust to minimum E Pulse width 10ns 1 us Amplitude adjust to maximum Bt PULSE DELAY s NORM 35n 1 4m i0m 1 Other switches e Pulse Norm Offset Off i PULSE WIDTH 5 10n gt ip im 1 Output Norm um 9 Int Load IN VERNIER Verniers Pulse period O Clock position Pulse width 12 O Clock position Amplitude 12 O Clock position 9 When examining the delayed traces notice whether the pulse generator produces a more ideal square pulse than the square wave from the function generator Look for ringing i e unwanted oscillations After you ve finished with the delayed trace e Set the scope to Horizontal Mode A so that you are no longer viewing the delayed sweep e Pull the time base knob out so that the mark on the inner knob is aligned with the two black marks on the clear outer knob now they will move together when you adjust them Be sure that the vertical coupling of is set to be DC e On the pulse generator vary the following and observe how the waveform changes o Vary the vernier for pulse period o Vary the vernier for the pulse width up to a maximum of 50 of the pulse period o Switch between NORM and COMPL output 35 Print these blank oscilloscope screens and use them to sketch waveforms shown on an analog scope 36 Print these blank oscilloscope screens and use them to sketch waveforms shown on an analog scope 37
56. e A maximum of three sentences to explain what was measured e g amplifier gain what was varied e g oscillator frequency how errors were estimated Results indicates a response is required where it is appropriate response should include table and or graph of results label each curve draw smooth curves through data points label axes and indicate units e g Hz mV estimate of errors for analog measurements as a column in a table or as a representative error bar on a graph sketch or print of the oscilloscope display if one was used and discuss briefly in a few sentences the features of the waveform to demonstrate that you understand the significance of the waveform timing diagram or truth table for digital circuits explanation of any problems you encountered Handwritten lab reports are adequate Typewritten reports are unnecessary Be brief but write in complete sentences For graphs you may use Graphical Analysis or other software If preparing your report consumes significantly more than two hours talk to your TA to ask if you are doing something that is unnecessarily time consuming Example lab reports are provided in the lab room for you to inspect Some instructors may not want error analysis included in the report Ask to be SYMBOLS USED IN THIS MANUAL For your information Instructions for you to follow Requires an answer or comment in your lab report RESISTOR COLOR CODE MULTIPLIER
57. e The op amp follower is not critical here if you use a voltage source with a low output impedance to drive it Connect the ADC0804 as shown Use LEDs on your prototyping board to indicate the three most significant bits pins 11 to 13 Pay careful attention to the grounds when using circuits with both analog and digital parts Although in this lab you may be asked to connect them together in general the analog ground and digital ground are different and some circuits might not work if you connect them together Use bench power supply see photo as an adjustable voltage source Be sure its negative terminal is connected to its ground and connect that ground to your circuit s ground 140 a b Clock Using an oscilloscope look at the waveform on pin 19 and print it Confirm that there is a 5 V 100 KHz clock signal present This frequency is determined by R and C as it was in the 555 timer A to D Conversion Connect a DMM to measure dc voltage across the differential input to the ADC i e between pin 6 and ground Tf it looks like too many LEDs are lighting up the input voltage may be jittering near the borderline between digital levels causing a fast alternation between one digital level and another and because of the fast clock speed it looks like all the LEDs are lit Try adjusting the input voltage slightly up or down Caution in the next step try not to exceed 5 0 V in
58. e following switch settings OUTPUT norm INT LOAD out PULSES DELA Y doesn t matter PULSE norm Produce a square wave with an amplitude in the range 5 0 5 5 V peak to peak and a period of about 1 3 sec slow enough that you can see the LED blink when it is connected later Set Apply the TRIGGER OUTPUT of the pulser to the external trigger input of the scope Use the scope s trigger menu to choose normal and external triggering Apply the OUTPUT across the LED and ground as indicated by 510 1 in the diagram Sig OUT Hook up the circuit shown in the diagram Use a 270 Ohm resistor in series with the LED Use an emitter resistor Rr 1k on the phototransistor Use the bench power supply to provide 5 VDC for Vcc Connect the CH1 10X probe to the output of the pulser and the CH2 10X probe to the emitter of the phototransistor to observe its output Align the optical parts on your prototyping board so that the lens of the LED faces directly toward the lens of the phototransistor with a separation of 1 cm The phototransistor s lens is highly directional so make an effort to point the LED exactly on axis with the phototransistor Perform the following test to verify that the beam of light from the LED is pointed at the phototransistor Hold a piece of paper immediately in front of the phototransistor so that it blocks half the phototransistor s lens as shown in the photo which is best seen in
59. e for partial credit for the part that does work e explain how you arrived at your error estimates Grading scheme grading factor prototype hardwired design 80 96 60 96 cleverness of idea how well it works how ambitious it is schematic diagram 10 10 specifications 10 10 quality of construction 15 safety 5 Error estimates require values from the manufacturer s specifications for the instrument For the multimeter parameters are reproduced in the preface to this manual for other instruments including digital oscilloscope you should refer to the actual manufacturer s User Manual Qualitative user judgments of how well you can read a display or jitter in the display are not good error measurements 149
60. e noise Connect the circuit shown in Figure 7 8 and apply a sine wave to the input If the output of the circuit exhibits clipping reduce the input amplitude if turning the function generator s amplitude knob isn t sufficient see if your function generator has an attenuation button which might be labeled 20 dB for example 95 a Differentiation Print the outputs of the differentiator circuit for a sine wave and a ramp wave inputs at a frequency 100 Hz Explain how your waveforms are consistent with the circuit taking the derivative of the input b Frequency response Forasine wave input vary the frequency while observing the input and output waveforms on the oscilloscope It is not necessary to record data for this step Discuss in one sentence how your observations are consistent with the description high pass filter C2 50 pF RI Ci R2 1k 0 01 LF 100 k out Figure 7 8 Op Amp Differentiator 96 7 Comparator You will observe how a comparator will output a relatively clean digital output 5V or OV depending on whether an analog input voltage is gt or a threshold voltage You will establish the threshold voltage using a potentiometer You will also observe an undesired oscillation in the comparator s output a d you will diminish this oscillation by adding positive feedback to the comparator Connect the comparator chip as shown below pin out is shown for 311
61. e power supply to two different voltages and measure each of these Does the value on the power supply s meter agree with the value measured on the multimeter within the error bars for the two measurements Asa rule remember that meters on a power supply are usually less reliable than multimeters Always make measurements of voltage and current with an external meter As always in both your notebook and report draw the schematic for whatever you connect including external instruments For this measurement it looks like the example below I ANEMIE LAMBDA Schematic Power supply 2 AC voltage and frequency No error measurements are required for this section Setthe AC DC switch of the multimeter to AC and reset the scale to maximum voltage Plug the primary of the transformer it is labeled 8 Vrms but you will measure this yourself into the AC outlet and measure the AC voltage of the transformer secondary The wiring in a building in the USA is nominally rated at 110 V rms but will vary from this value Since this is connected to the primary of the transformer and the voltage on the secondary is a fixed fraction of the primary voltage you may find that your output voltage is not exactly the level printed on the transformer The electrical generators used by utility companies produce a 60 Hz voltage If your multimeter has a frequency Hz feature use it to measure the
62. e time Record the value of this specification e Pulse generator The rise time for the pulse generator is finite but it is much better than for an inexpensive function generator Pulse generators are optimized to produce excellent pulses with fast rise times function generators are not e The phototransistor and LED have finite response times here are the data from the manufacturer s specifications PNA1801L phototransistor 4 usec typical HLMP C115 LED 30 nsec typical e The HLMP C115 LED cost 0 60 is one of the fastest visible LEDs that I was able to find Usually in applications where the response time of a light source is important you would not choose an LED instead you would choose a laser diode which is much faster cost 10 Replace the HLMP C1115 with any common LED for example a red diffused LED like the one used in Experiment 8 and repeat the measurements of the time response for that LED For both measurements HLMP C115 and the other LED identify the component or instrument you believe is most responsible for the finite rise time that you measured and discuss briefly how you came to that conclusion When finished reset the CH1 and CH2 menus so that it has Probe 1X not Probe 10X so that this does not confuse measurements made with this scope in following labs Note manufacturer s specification is for parameters Ve 10 V Ice 1 mA Rz 100 Your result might be slower at para
63. each test lead of the multimeter nsert two wires into various holes in the prototyping board Checking for continuity convince yourself that the board is connected as shown below what it looks like from outside connections under the surface 10 Potentiometer as a Voltage Divider no response needed for lab report Examining Figure 1 9 use the potentiometer instead of fixed resistors to hook up the circuit Be sure that you apply the input voltage across the two terminals that have a fixed resistance The wiper of the potentiometer should be the output terminal in the middle right of Figure 1 8 Observe the output voltage while turning the potentiometer If the output voltage increases as you turn the knob clockwise you are done otherwise change one of the output connections 11 Familiarity with switches no response needed for lab report An SPST switch has two terminals while an SPDT switch has three Use a multimeter s continuity check function to test these two switches Become familiar with which terminals become connected or disconnected when the switch is in a certain position So SPST d SPDT w 15 Lab 2 AC Measurements REFERENCE Horowitz and Hill Sections 1 13 1 18 1 19 Appendix A Oscilloscope INTRODUCTION The object of this lab is to learn measurement skills You will become familiar with the oscilloscope function generator and pulse generator in measuring time v
64. eads to bring the diode into conduction when it is forward biased If you suspect that you burned up a diode check its diode drop using a multimeter to see if it is still good CAUTION In this lab it is possible to burn up components if you are not careful to make sure everything is correct before turning on the power e Please note all caution statements in these instructions e Double check before turning power on e When using the decade box do not set the load resistance below 50 4 Learn to use the digital oscilloscope amp a scope probe no written response required Connect a scope probe to the digital oscilloscope as shown in the photos below A scope probe has two settings 1X and 10X photo shows 10X setting This notation might be confusing the 10X setting has the effect of dividing not multiplying the signal by a factor of ten An advantage of a 10X probe is that it has a higher frequency response so that if you need to view signals gt 1MHz you should use a 10X probe In most of this course you will view slower signals and a 1X probe is adequate 42 Trig d Indicates the scope is triggering amp updating its display o Arrow indicates UTE zero voltagd gt level for OU ES BOO Channel 1 x Indicates N m trigger T UNE 2519 Frea 1 000kHz 6
65. eat with a capacitance of 1000 uF Using the capacitance of 100 uF try a smaller load resistance CAUTION do not set the load resistance below 50 List your results Compare with the calculated values of the DC output and ripple voltages See Horowitz amp Hill 2 Ed p 46 50 Discuss in two or three sentences two factors that cause ripple to become worse Note that in a power supply a bigger capacitance gives better filtering but with the tradeoff that the component is costlier larger and heavier Note that the smaller the load resistance i e the larger the current that the power supply must deliver the worse the ripple Do not disassemble the full wave rectifier yet 5 Voltage regulation with 3 terminal regulator ouem TO 92 Plastic Package Z 3 terminal voltage regulators are easy to use a From the outside it looks like a transistor but on the inside there is a good regulator that makes use of negative feedback It features thermal protection so that it is hard to burn up GND In 05007744 3 out GND Bottom View a Simple test Connect the 78L05 regulator on your prototyping board as shown below For an input use the 12 Volt power supply that is built into your prototyping board or an external power supply set to about 10 V 4 7 uF 0 01 uF to guard to provide against short oscillations term smoothing Confirm that the output is nearly 5 V
66. ect some inputs to your digital circuits For a LO input use a wire between the digital input and ground For a HI input use a 1 k resistor between a digital input and 5 V An alternative method more convenient than using resistors as described above requires using a prototyping board that has built in switches for logical HI and LO inputs These provide suitable inputs for logic circuits and don t require resistors DATA SWITCHES SGvw1 swe sws3 Swa On your prototyping board Use two wires to connect the 5 V and GND outputs of the power supply to a strip that looks like Soo SSS LOGIC INDICATORS L4 L2 L3 La Your prototyping board has built in LED Logic Indicators that you can use for displaying a signal As an alternative you may use a discrete LED as an indicator but be sure to use a series resistor as described below How to read part numbers The part number consists of numbers and letters Example 5 741500 the SM indicates that the manufacturer is Motorola and this is not important 7400 indicates that the chip is a quad 2 input NAND and the LS indicates that it is a variety of TTL that is low power Schottky input Other chips that perform the same logical function are 7400 plain old fashioned TTL and 74 High speed variety of CMOS All of these chips are logically identical and their pin configurations are the same 104 About CMOS
67. ended unless you already have the required skills and tools use a grounded box use grommets amp strain relief for power cord cover all 110 VAC so that it is unreachable when the box is closed use a terminal strip with crimp on lugs for 110 VAC de burr holes after drilling sheet metal Wires to front panel Circuit boards Testing Project Tips Planning bundle them with tie wraps for neatness line up ICs and other parts in neat rows don t cross wires over chips use sockets for chips test your ideas on prototype boards first show the instructor that your prototype board version works for partial credit in case your final circuit doesn t work As with all research projects Plan ahead Procrastinators will learn a hard lesson Expect your project to require 3x as long as you expect Expect things to go wrong 146 Designing A simple idea that works is better than a grand idea that fails Avoid designing circuits with high speed high frequency high voltage or high current Design a circuit mainly or entirely based on components that you already understand like op amps and digital gates Many successful projects begin with a fairly simple idea then add bells and whistles After your basic circuit is tested successfully extra features such as displays or adjustable settings can be added Do this if your basic circuit idea does not have enough components Purchasing Buy from local sources wh
68. erever possible Plan well ahead if you buy by mail Buy several spares for every semiconductor chip or high power item Obtain data sheets for all semiconductors and chips If you need a microphone choose an electret model Testing tips Begin by testing your circuit one section at a time on a prototype board Don t assemble a big circuit all at once and expect it to work You will have bugs to work out and this is easiest to do if you assemble it in stages one section at a time For analog circuits use an oscilloscope to observe AC signals Buy a small prototyping board of your own so that you can keep your project assembled as you work on it Otherwise you will have to disassemble it so that other students can use your board A single strip or two may be enough If your circuit s inputs are to come from a transient source such as pushbuttons or random pulses test your circuit with a repetitive waveform from a function generator A few students choose to test their design on a computer using Spice based circuit simulation software such as Multisym before building it 147 Power supply tips Many students have problems because their circuit draws too much current for their power supply Give some thought to choosing which power supply you use If your circuit consumes more than 100 mA from a 5 VDC power supply use a bench power supply HP or Lambda for example not the prototyping board Otherwise your circui
69. f you didn t measure hfe assume it is 100 Note that resistors and R appear to be in parallel with hfe times the emitter bypass Use the 5 kHz result see above for the emitter bypass impedance v the theoretical gain Ay re Zeb at f 5 kHz assuming re 25 1 mA b Operating point Connect the circuit shown above using a prototyping board In wiring it up it may be easiest if you use three of the long thin rails on the prototyping board for 12 V GND and 12 V 74 Measure and compare to the calculations above i the dc base bias and the emitter potential ii the collector current use Ohm s Law and a measurement of the potential across the collector resistor to determine this Sync output of c Voltage gain function generator i with emitter bypass capacitor Setup the function generator to produce a 5 kHz sine wave with a low output amplitude Set up the oscilloscope to make a dual trace measurement of the input and output of the amplifier Connect the SYNC output of the function generator to the EXT TRIGGER input on the scope and use external triggering Make sure that the grounds of the oscilloscope the prototyping board and the function generator are all somehow connected Adjust the function generator amplitude to produce a good sine wave on the output of your amplifier If the output waveform is saturated or clipped reduce the input amplitude from your
70. frequency of the transformer output Transformer Return the multimeter s ac dc switch if there is one to dc 3 Resistance Setthe function switch to Ohms Check the meter by shorting the test leads The meter should read zero ohms a Tolerances note if you are color blind skip this step and inform the TA For this step only use the box of assorted resistors Measure the resistance of four of your resistors Use only resistors with four bands resistors with five bands are uncommon sometimes the fifth band is used to indicate temperature sensitivity or to provide an additional significant digit for the resistance value Determine the fractional error from the nominal value from the color code If you are color blind you will be unable to identify the colors on the resistors Inform the TA so that you can be excused from this step Otherwise in this course you will need to rely on your multimeter to determine your resistor values if you are unable to read the color code Make a table with seven columns color code nominal value tolerance measured value multimeter scale multimeter error multimeter error as a fraction of measured value How many of the values fall within the specified tolerance As always draw the schematic For this measurement see Fig 1 3 b Series amp parallel Choose two resistors that are within a factor of ten of the same value Wire them up in series a
71. function generator If it is necessary to reduce the input amplitude further wire up a 1 k potentiometer as an adjustable voltage divider and connect it between the output of the function generator and the input of the amplifier Measure the input and output amplitudes using the oscilloscope Compute the gain and compare to the theoretical value using measured component values from above Is this an inverting amplifier ii without emitter bypass capacitor Repeat these steps with the bypass capacitor disconnected Note if clipping occurs check that you have not shorted the emitter Cr d Input impedance Measure the ac input impedance of the circuit with the emitter bypass Use the procedure from Lab 4 Compare to the theoretical value from above e Output impedance Measure the ac output impedance using the procedure from Lab 4 75 Lab 6 Optoelectronics REFERENCE Horowitz and Hill rise time p 268 optoelectronics pp 590 598 INTRODUCTION The term optoelectronics refers to semiconductor light sources and light sensors Light sources include light emitting diodes LED and laser diodes In this lab you will use a visible LED LEDs are cheaper and are usually used as visual indicators rather than for high speed communication Laser diodes are more expensive and are used for high speed fiber optic communication In addition to their high speed in turning on an
72. gering of an oscilloscope is often confusing for beginners A trigger is an event that starts the horizontal sweep or trace see Figure 2 1b This trigger event is defined by comparing two voltages the moment when the trigger source voltage exceeds the trigger level voltage is the trigger event The trigger source can be an external voltage EXT that you connect to the oscilloscope or it can be one of the vertical inputs CH1 or CH2 Usually you must choose between AUTO and NORM triggering NORM triggering will allow a trigger only if there is a trigger event AUTO triggering will cause a trigger even if there is never a trigger event the beginner will usually use this setting since it always yields a display voltage trigger source waveform trigger level time trigger event trigger event with positive with negative slope slope Figure 2 1 b Oscilloscope triggering 18 f 0L108 171933 AIG SLIOA LHO WE o LI NOILISOd NOILISOd 7 435 4MS 8 NOILISOd 3940980111980 ZHW One use of the oscilloscope is to measure relative phases between two waveforms This is done by adjusting both waveforms so that they are symmetric about the horizontal line in the middle of the screen Then note the time delay At between the zero crossings as shown in Figure 2 2 This corresponds to the phase shift which is 360 At T Figu
73. gure 1 9 large value resistor 15V load Figure 1 9 resistor Testing a current source This combination of a battery in series with a large resistor will act as a current source provided the load resistance connected to the terminals is small The current iS IT V R1 RZ V R1 1 RL R amp V R for Ry lt lt This is a crude current source because the current depends on the load resistance especially when is not much less than You will build a better current source using a transistor in Lab 4 Connect three different load resistances across the terminals and measure the current through the load resistor and the voltage across it in each case a Whatis the most accurate way for you to use a multimeter to measure current passing the current directly through the meter or using the meter to measure the voltage drop across a known resistance and computing the current from Ohm s Law b Make a table and or graph of current vs load resistance c Compliance Determine the range of load resistance over which the current remains constant to 10 Note In Lab 4 Junction Transistors you will need this result again record it so that you can find it then 12 8 Voltage Divider note no error measurements required for this part A voltage divider reduces a voltage to a desired level Measure the values of the resistors shown in Figure 1 10 then wire up the circuit
74. he power supply The purpose of resistor R3 is to reduce the gain to avoid excessive high frequency noise common emitter amplifier Use the following resistor values 82k RC 68k 12k RE 1k 22200 a Calculations Measure your component values If your multimeter has a beta measurement feature use it to measure hfe 73 Compute the following quantities i Predicted value of the dc base bias and the emitter potential assuming an 0 6V B E drop ii Predicted value of the dc collector current and the dc bias on the output Compare the predicted value of the dc bias calculated in ii to 0 5 Vec Explain in terms of an undesirable circuit phenomenon that you wish to avoid why the value of the dc bias you predicted is desirable iii the impedance Zep of the emitter bypass i e the parallel sub circuit consisting of the emitter resistor Re amp the capacitor in series with resistor R3 for the following frequencies 0 100 Hz 5 kHz Recall that e aresistor R3 and capacitor C that are connected in series have a combined impedance Zseries R3 Zc where Ze 2j oC is the impedance of a capacitor at frequency w 2f e aresistor Re in parallel with impedance Zseries has total impedance 1 Zep 1 Re 1 Zseries e Also recall that the magnitude of the resulting impedance is computed from its complex value as IZI Z z iv the input impedance at 5 kHz i
75. he trace fills a large portion of the screen If it fills only a small portion of the screen your measurements will not be very precise Use GND input coupling to find where zero volts is and use the vertical position to locate this on a gridline f your function generator has a DC offset adjust it so that the bottom of the waveform is at zero volts Draw the oscilloscope display for the square wave and indicate the voltage at both the bottom and top of the waveform Adjust the oscilloscope horizontal time base so that the discharge time takes a considerable portion of the display Use the horizontal position to locate the waveform so that the triggering time is at a convenient gridline Your display should look like the figure above labeled charging Change the oscilloscope trigger slope between and to see the difference it makes a Charging Determine the charging time constant from the oscilloscope display Estimate your errors Calculate the ratio of your charging time to RC b Discharging Change the scope triggering slope to see the discharge portion of the trace Your display should look like the figure above labeled discharging Determine the discharging time constant from the oscilloscope display Estimate your errors Calculate the ratio of your discharging time to RC 29 Figure 2 3 a R input oscilloscope CH1 displays the input waveform CH2 displays the output wavef
76. his exercise is intended to train you to look up manufacturer s specifications for an instrument which is a routine all physics experimenters should follow in their research 45 Diode Limiter Diode limiters can be used at the inputs of small signal instruments to protect against accidental application of large input signals This is a low current application so you use signal diodes not power diodes Like most diode circuits this has a resistor in series with the diode Without this resistor the diode would burn up when it conducts Using small signal diodes connect the input of the circuit shown below to the function generator set to about 1 KHz Check that the 20 dB attenuator switch on the function generator is activated Try sine triangle and square waves of various amplitudes Try a low amplitude for the oscillation and adjust the function generator s dc offset to observe the effect of clipping Print the output of the clamp circuit for sine wave inputs two ways o With an output waveform that is severely clipped o With an output waveform that is only slightly clipped Comment quantitatively on the output amplitude where clipping is strongly observed and identify the diode s parameter that determines this amplitude in 1k out Diode Limiter 2 Diode Clamp Connect the clamp circuit in the figure Use the 5V power supply built into your prototyping board This is a low curren
77. honesty amp the required disclosure e Your design must be your own e At the beginning of your grading you will present a disclosure stating which portions of your circuit are your ideas and which portions are copied from another source such as this lab manual the textbook a specific internet page etc e tis plagiarism to fail to omit anything from your disclosure e 15 plagiarism to copy entire designs from books the internet or someone they know students who do this are detected because they are unable to answer questions about their project at the time it is graded Requirements Your circuit must include a minimum number of electronic components that will be agreed upon when you discuss your ideas with the instructor Copyright 2015 John A Goree Edited by John Goree 5 Jan 2015 Money Purchase your own components from vendors such as the following e Ul Engineering Electronics Shop 2018 Seamans Center http www engineering uiowa edu eshop e DigiKey tel 1 800 DIGIKEY http www digikey comTwo ways to build You must choose either Hardwired projects Safety Connectors Holes to build it on a prototype board recommended to build it hardwired in a box with a battery or power supply If your final project is built on a prototype board it must be more ambitious If it 15 hardwired in a box it must meet good standards for safety and quality of construction This is not recomm
78. ication Resistors 1 KO 3 3 10kQ 22 33 1 MQ Capacitors 0 1 uF 58 Amplifier Transistors NPN Silicon MAXIMUM RATINGS me 7 Collector Emitter Voltage Collector Base Voltage Total Device Dissipation Ta 25 C 625 mW Derate above 25 C 5 0 mW C Pp 1 5 Total Device Dissipation Tc 25 C Watts Derate above 25 C CASE 29 11 STYLE 17 Ba Operating and Storage Junction TO 92 TO 226AA Temperature Range THERMAL CHARACTERISTICS Characteristic m coULECTOR Thermal Resistance Junction to Ambient CIW BASE ELECTRICAL CHARACTERISTICS T4 25 C unless otherwise noted 0 1 weite 5 m unt OFF CHARACTERISTICS Collector Emitter Breakdown Voltage V BR CEO 40 Vdc 1 10 mAdc lg 0 Collector Base Breakdown Voltage ViBR CBO 75 Vde 1 10 Adc le 0 Emitler Base Breakdown Voltage ViBREEBO 6 0 Vde lg 10 nAde 1 0 Collector Cutoff Current IcEx 10 nAdc Voe 60 Vdc Vggieg 3 0 Collector Cutoff Current lego uAdc Veg 60 Vde lg 0 0 01 Vcg 60 Vdc lg 0 Ta 150 C 10 Emitter Cutoff Current 10 nAdc Ves 3 0 Vde 0 Collector Cutoff Current 10 nAdc Vece 10 V Base Cutoff Current Ibex 20 nAdc Vcg 60 Vdc Vegir 3 0 Vdo ELECTRICAL CHARACTERISTICS Ta 25 C unless otherwise noted Continued a ee unit ON CHARACTERISTICS
79. ite a simplified version of this formula valid for A 1 c Write an even more simplified version valid if A 1 and Vou Vosc 2 2 Circuit A setup Vosc measure Vout here PO Conceptual Vosc equivalent circuit measure out Zin here 61 PROCEDURE C C Figure 4 1 B B PNP Figure 4 2 NPN Transistor pinouts NPN PNF B Examples DN 2N2222 22907 B 2N 3904 2N3 I06 oJ C TO 92 case TO 18 case The 2N3904 and 2N4400 are similar except that e 2N4400 withstands a higher collector current and is therefore better suited for switching circuits you may you may substitute 2N2222 for 2N4400 e 2N3904 is better suited for signal amplifier circuits 1 Multimeter Check of Transistor This test is similar to the one you did in Lab 3 with the diode If you are unsure of how to do this test first go back to Lab 3 and repeat the diode test with a diode 62 collector base 1 x B emitter E Figure 4 3 a Diode equivalent Use your multimeter s diode check feature It will display the forward bias voltage Verify that the transistor looks like two diodes as shown in Figure 4 3 b Beta measurement Jf your multimeter has special connectors labeled C B E then it has a transistor check function For some multimeters this will display the beta or pp Try it For the 2N3904 beta is typically hpg 210 Emitter
80. lse begins on a major division on the time scale Adjust the vertical position so that the baseline for the pulse is similarly on a major division line Adjust the pulse amplitude so that the phototransistor output varies an integer number of divisions Choose appropriate scales for the vertical and horizontal axes so that the interesting part of the waveform fills a large fraction of the display Print out your oscilloscope display resembling the screenshot shown here Record the value of rise time indicated by the oscilloscope 83 Compute the ratio V Vo Vr Vo expressing your answer as a percentage 1 XX This result should be the same regardless of the amplitude of the waveform or the student performing the test it is a criterion determined by the oscilloscope s manufacturer Things to know about measuring speed The rise time that you measure for the output of the phototransistor is tens of microsec This is the result of the rise times of several components and instruments e Oscilloscope The oscilloscope has a bandwidth that is probably printed on top of its front panel If it has a bandwidth of 100 MHz for example it will have a rise time of about 0 35 100 MHz 3 5 nsec Faster oscilloscopes cost more e Probe The 10X probe also has a bandwidth that limits how fast the measurement of the waveform can be made look in the manufacturer s manual for the 10X probe to find the specification for its ris
81. lse train clock 132 M AM OL MAE VLC tm E gt DLE DE eslep mee me Bette M Lab 10 circuit as wired on the prototyping board at the end of the Lab 133 PRELAB Identify all formulas used in this lab While an analog voltage can have an unlimited number of values a digital signal has a limited number of discrete values How many discrete values can be represented by 8 bits of data Whatis the sensitivity mV per degree C of the temperature sensor you will use 134 PROCEDURE 1 555 Timer used as an oscillator a b Timer circuits are common in many of the instruments that are home built in research laboratories A favorite and easy to use chip is the 555 timer or a modernized version such as the 7555 With this chip you can easily build a simple oscillator or other waveform generator Using the prototyping board build the circuit shown in the figure Use 5 V from your prototyping board for V Vec 15 V should work too As with many circuits this one can benefit from adding a filter capacitor across the power supply leads to reduce problems arising from voltage drops appearing on the power supply It is recommended to add a 10 uF capacitor across the power supply pins 8 and 1 position this capacitor within a few millimeters of the 555 chip Note the polarity of the leads of the electrolytic
82. m the transformer has a larger output b Full Wave Rectification CAUTION In this part carefully check the polarity of your diodes before turning on the 110 VAC power otherwise you will burn up the diodes Measure the output waveform of the full wave bridge circuit in Figure 3 3 Do not attempt to measure the input waveform Use a 1 load resistor Print the output waveform Compare to the half wave rectifier 49 4 Power Supply Filtering Scope Input 110 VAC Scope Gnd Figure 3 3 Full wave rectifier bridge circuit The input is 110 VAC line voltage CAUTION In this part carefully check the polarity of your capacitor before turning on the 110 VAC power Starting with the full wave rectifier circuits in scope Figure 3 3 add a capacitor C 100 uF across the load input resistor as shown in Figure 3 4 Note that capacitors 100 pF of such a large value are polarized one of the R capacitor s two leads is marked or Measure the DC output voltage Scope ground Measure the PP AC ripple using the Figure 3 4 Filler Capacitar oscilloscope Try this two ways e first with DC input coupling e repeat with AC input coupling You should find that AC coupling allows you to use a smaller scale in Volts div and thereby make a more accurate measurement Print the output waveform Discuss in one sentence how the filter capacitor improves the performance of a power supply Rep
83. meters different from these 84 8013B PULSE GENERATOR HEWLETT PACKARD AMPLITUDE V MAN RATE Hz PULSE PERIOD s VERNIER 1 DEXTC 20n 1p Eum 5 Am 10m 50M 1M 10 M da 20 PULSE DELAY s VERNIER CERNIERA ERNEA PULSE DOUBLE NORM 35n lp gt gt 10 1 6 PULSE WIDTH s VERNIER x od C SQUARE WAVE 110n tp Im 10m 1 E TRIGGER OUTPUT OUTPUT OUTPUT NORMICOMEC indicated in instructions Tek Tria d M Pos 15 00 us MEASURE lain Illa pli ld olli CHI Pk Pk 5 204 CH2 Pk Pk 5 00 CH1 SESESSHE SSNS SSS SEE OES Freq E E E 55 5539333535 1995 5 553 2 481 BEEN ZEE CH1 Rise Time 33 2 ns CH2 Rise Time 6 170 us CH1 200v 100 M5 00us CHI J 3 04 REFERENCE Horowitz and Hill Sections 4 01 4 09 4 11 Appendix 411 datasheet INTRODUCTION The operational amplifier op amp is an integrated circuit i e chip is a multistage transistor amplifier with a differential input has a high input impedance 1012 Q for J FET input op amps is usually used with an external feedback network can amplify or perform mathematical and logical operations can operate from DC to MHz frequencies depending on the op amp model requires bi polar power supply typically 15 V The comparator is similar to an op amp but it is used for a different
84. mode A time base A sec div 1 ms CAL knob fully clockwise to click var holdoff NORM A trigger P P AUTO A ano B SEC DIV level turn to middle of knob s range a so slope rising slope S 2 S 20 amp 10 A amp B INT CH1 ms A source INT A ext coupling DC These instructions are for Tektronix 2235 other analog oscilloscopes are similar 25 Once you have found a trace that looks like a horizontal line use the vertical position knob on CHI to position the trace in the center of the display Then change the CH1 coupling to DC Connect the output of an adjustable power supply to the oscilloscope input You should see a trace at a non zero voltage Change the coupling back and forth from GND to DC to see the difference Set your power supply to three different DC voltages and measure each voltage with both the oscilloscope and the digital multimeter Adjust the display intensity as low as practical so that the trace is a thin line Compare the DC voltage measurements of the oscilloscope and the digital multimeter Report the measurement uncertainty error values based on the specifications for the multimeter and the oscilloscope and your impression of how precisely you can read the oscilloscope display Which is more precise the meter or the oscilloscope b AC Voltages Connect the function generator to signal input CHI of the oscilloscope Setthe f
85. n Use a wire on your prototyping board instead of a mechanical switch Using the 5 Volt power supply that is built into your prototyping board wire up an NPN transistor as a cold switch as shown in Figure 4 9 The lamp is the load here The 10 k resistor is not essential it makes sure that the base is near ground potential when the switch is open a Cold switching hc iind jg i Figure 4 9 Cold switching Verify that the lamp is turned on as you close the mechanical switch and off as you open it b Current through the switch Setting your multimeter to operate in its highest current range to begin with use it to measure the current flowing through the lamp Setting your multimeter to measure voltage measure the voltage drop across each of the two resistors Compute the current flowing into the base 68 Comparing these two currents is it true that the cold switch allows you to switch a larger current through the load lamp than passes through the actual switch c Saturation mode With the switch closed use your multimeter to measure the DC voltage drops Vcg and Vpg Is Vc lt Vp as expected for saturation d Cold switching from a pulse generator s output Replace the manual switch with the pulse generator s output as shown in the diagram so that a high output from the pulse generator will cause the lamp to light pulse 47 lamp gene
86. nd then in parallel using the board with three terminals Measure the series and parallel resistances Calculate the expected resistances use measured values from part a and compare with your measurements including error values calculated using propagation of errors 4 Potentiometer no response needed for lab report The potentiometer has three terminals two are the ends of a fixed resistor and one is the wiper Using the two leads of the multimeter to test different pairs of the potentiometer terminals and by turning the potentiometer while observing the resistatance a determine which terminal is the wiper and b verify that the resistance between the other two terminals does not vary as the potentiometer is turned Determine which pair of terminals has a resistance that increases when you turn the potentiometer clockwise as viewed from the top resistive strip terminal w m i erminals A wiper r4otary What s inside Schematic symbol This is one of two instances in this lab where you are asked to use propagation of errors 10 5 Continuity no response needed for lab report With the function switch set to Ohms touch the two test leads together while watching the display Now set the function switch to continuity Depending on your multimeter this might be indicated with a symbol like this Touch the two test leads together and listen for the beep Caution A
87. ng Vmax Vmax 0 63 Vmax 0 36 Vinax En RC PR time zd RC ME time discharging charging Rules of thumb RC product RC is called the RC time constant or simply RC time When the input voltage of an R C circuit changes from one level to another the output voltage will approach its final value asymptotically RC is the time required for the output to swing by 63 toward its final value Because 1 exp 1 2 0 63 SRC is the time required to swing within 1 of the final value Because exp 5 2 0 007 1 28 Measure the actual values of a 5 k resistor and an 0 003 uF capacitor Connect the series R C circuit to a function generator and an oscilloscope as shown in Figure 2 3 a and 2 3 b This circuit is shown two ways to help you figure out how to wire it up Use a wooden board with binding posts Connect a multimeter to a function generator to measure its frequency Setthe oscilloscope for external triggering EXT and connect the trigger input to the SYNC output of the function generator BNC connector labeled TTL CMOS see photo Setthe function generator to produce square waves with a peak to peak Sync output amplitude of about 5 Volts Set the frequency so that itis appropriate for of function measuring the time response of the R C circuit the period r l fshould 9eherator be 10 RC Setthe oscilloscope vertical voltage scales to be the same choosing a scale so that t
88. ng as the trigger source the scope channel CHI or CH2 that you have connected to the counter s output Forthe 90 chip to achieve the desired output waveform it may be necessary to use a pull up resistor on the output pin 7 To do this select a resistor with a value between 2 kQ and 100 kQ it s not a critical value and use it to connect the output pin to 5 TA note 2015 the above instruction has changed please test it and report to Prof Goree Use the 90 to perform the following operations a Divide by 2 Connect the pulse input to the 2 input Print the waveforms Discuss briefly the meaning of the phrase divided by two as itis shown by your waveforms identifying which parameter is divided b Divide by 5 Connect the pulse input to the 5 input 122 Printthe waveforms Explain how the waveform is divided by five Note the asymmetry of the output waveform c Divide by 10 Connect the 5 output to the 2 input Use the scope to observe the 2 output Print the waveform Discuss briefly the meaning of the phrase divided by ten as itis shown by your waveforms identifying which parameter is divided d BCD Counting Binary coded decimal BCD is the same as binary for numbers 0 to 9 For larger numbers it is different BCD is composed of groups of four binary digits where each group represents one digit in base 10 Example 314 decimal 3 1 4 BCD 0011 00
89. nnect the transformer to power diodes they can melt and they are costly Instead use alligator clips Caution take care in arranging components on your prototyping board to avoid shorting the alligator clips e Keep the two alligator clips 22 inches apart so that they can t touch one another Don t let the alligator clip touch ANY undesired conductor as that can also cause a short Mini grabber connector f using an analog scope set the oscilloscope as follows input coupling DC CH1 and CH2 vertical mode BOTH and either ALT or CHOP this is the dual trace feature In the figure below the waveforms are shown as they would look if the input voltage had a 1 V amplitude Notice the 0 5 V diode drop Also notice the time interval shown between the dashed lines when the input voltage is positive but not large enough for the diode to conduct 0 5 V diode drop 0 5 V diode drop Half wave rectification shown for input of 1 V amplitude time Adjust the variac to indicate 10 VAC output Measure the P P amplitude of o the input voltage V from the transformer 48 o therectified sine wave output voltage V across the 1 k 2 load resistor Print the input and output waveforms and compare the peak output voltage with half of the PP input voltage Explain the difference Repeat without the variac i e with the transformer powered directly from a 110 VAC outlet so that the waveform fro
90. ns when the input voltage exceeds a threshold voltage 136 FUNCTION TABLE 5N74121 N PACKAGE TOP VIEW ee E NC NC x 7 i A1 NC H X A2 Raxt Cext 1 cor EE a Rint L x t GND NC x L t ee The One Shot you will use has a Schmitt trigger input for the B input Schmitt trigger inputs fire when the input exceeds an upper threshold and reset when the input voltage drops below a lower threshold This helps to produce a jitter free pulse from a noisy input signal Setup for parts using internal resistance parts a and b Referring to the specification sheet connect the 121 on the prototyping board as follows Connect an 0 1 uF capacitor between pins 10 and 11 I Q output 8 NC 2 NC 9 Connect to Pin 14 to use internal resistor 3 input Al GND 10 External capacitor 4 input A2 GND 11 External capacitor 5 input B 12 NC 6 Qoutput 13 NC 7 GND 14 5 V For using INTERNAL For using EXTERNAL resistance 5 V External resistance C Internal resistance 137 a b For using internal resistance Set up the pulse generator to apply a square wave with 7 V peak to the input of the one shot Use a frequency f 1 kHz varying the input amplitude downward until no output pulse is generated measure the trigger voltage Measure the output pulse width Compare to Rint C In 2 assuming the manufacturer s nominal value Rint 2k
91. nsor output to a digital multimeter and touch your finger to the sensor and observe the change in the output voltage Describe your observations Discuss how you could use the ADC circuit to make a digital thermometer 143 Vs 4V TO 20V LM35 FIGURE 1 Basic Centigrade Temperature Sensor 2 C to 150 C TO 92 Plastic Package BOTTOM VIEW LM35CZ LM35C AZ or LM35DZ 144 LM35 Vour DS0055164 Choose Ry 5 50 pA V 1 500 mV at 150 C 250 mV at 25 C 550 mV at 55 C FIGURE 2 Full Range Centigrade Temperature Sensor PROJECT Toward the end of the semester you will design and build a circuit of your own to meet whatever purpose you like Project planning This project is not like an ordinary lab assignment It is more like a part of a thesis project To be successful you must do project planning Project planning entails e making a schedule for yourself e allowing time to receive purchased supplies e allowing time to assemble test and debug your experiment and finish it on time e budgeting for costs An original idea The circuit you design may be analog digital or both The circuit could arise from your thesis project or it could complement an existing instrument for example your guitar or stereo You could make a game a circuit that demonstrates some mathematical or scientific concept or something for a hobby It is up to your imagination Academic Dis
92. o be made for next year Lab 1 DC Measurements REFERENCE Horowitz and Hill Sections 1 01 1 05 Appendix C Resistor color code Appendix E How to draw schematic diagrams INTRODUCTION This experiment has the following objectives Become familiar with multimeter prototyping board resistor color code reading a schematic diagram wiring a circuit Study a current source A voltage source Figure 1 1 such as a battery or power supply is inherently a device with a low internal resistance It should provide a constant voltage for a wide range of currents A current source Figure 1 2 on the other hand should provide a constant current to a wide range of load resistances Copyright 2015 John A Goree Edited by John Goree 5 Jan 2015 FLL Figure 1 1 Figure 1 2 Voltage source Current source mm mm c series AAA AAA Rseries Ri T R2 parallel Series and parallel circuits Study a voltage divider A voltage divider is two resistors connected in series voltage divider Vout Vin R2 R1 R2 EQUIPMENT Lab supplies Digital multimeter BK Model 388 HD Battery L5V 2 DC power supply Box of assorted of resistors Switches with wires soldered on SPST SPDT Potentiometer with wires soldered on preferably gt 1k Resistor substitution box with 1000 Q decade or higher for top decade 8 V transformer Prototyping board Two short solid
93. olts An ideal voltage regulator supplies the same output voltage regardless of the input voltage as in test c below regardless of the output load as in test d below b Use as a power supply regulator Now connect the input of the 78L05 regulator as shown below to the output of the power supply you built in step 3 Include a 1 kQ load resistor 51 5 V output 0 01 uF 2 RL y PRI filter 3 terminal capacitor regulator Turn on the power supply and observe the output voltage Compare to the filtered output without regulation as measured in step 2 c Regulation as the input voltage is varied Now plug the transformer of your power supply into a variac instead of into 110 VAC Connect a multimeter to measure the Volts ac from the transformer s output when it is connected to the variac Set Ry to 1 Adjust the variac output voltage beginning at110 VAC and going downward using the printed scale on the top of the variac Caution Do not operate the Variac variac at voltages above 110 V Confirm that the regulator maintains the same 5 Volt output over a wide range of AC voltage typically from 80 to 110 VAC d Regulation as the load is varied Disconnect the variac Connect your multimeter to measure current through the load Notes e Recall that a current meter should be in series not in parallel as it is for voltage e If you multimeter appears
94. or bar for f delay in msec error bar for delay in msec phase in degrees error bar for phase in degrees Tip to save time it s quicker to do both the amplitude and phase measurements for frequency before changing the frequency 3l ndicate whether the output is delayed compared to the input or vice versa ii Plot the phase curve on a graph with a semi log scale linear flog Compare with a theoretical plot of the phase shift on the same graph 11 What is the phase angle measured and theoretical at f 21 2z RC 5 High Pass Filter Use the same 5 resistor and 0 003 uF capacitor as in the R C low pass filter above but swap them to make a high pass filter High Pass Filter 0 003 u 5k V Instead of the analog oscilloscope use the Agilent 34410A multimeter to measure the input voltage rms and output voltage rms Make the amplitude response measurements and plots omit the error values Use the following frequencies 100 kHz 50 20 10 3 1 0 3 0 1 kHz also include a frequency of f 1 2zRC in this sequence as calculated from measured values of R and C 6 Measurement skills no response necessary for lab report Use your remaining time in the lab session to familiarize yourself with the oscilloscope and pulse generator Connect the function generator to the oscilloscope as shown SCOPE CH1 CH2 EXT PRY GEN FUNC SYNC OUT
95. orm BNC cable SYNC OUT FUNCTION labeled TTL GENERATOR red wire OUTPUT banana plug cables red wire Figure 2 3 b black wire 30 4 R CLow Pass Filter a Amplitude Response Use the same circuit as above in Figure 2 3 b Setthe function generator to produce a sinusoidal output with an amplitude of about 4 or 5 V peak to peak Use a 1 2 5 frequency sequence from 500 Hz to 10 Hz i e 500 1000 2000 5000 Hz Also include a frequency of f 1 22RC in this sequence as calculated from measured values of R and C 1 Record a table of your data with columns for f HZ error bar for f Vin oscilloscope scale for Vin error bar for Vin Vout oscilloscope scale for Vout error bar for Vout Vout Vin 1 Plot the voltage with log log axes with frequency on 5 out in the horizontal scale Make a theoretical plot of Vout Vin on the same graph You may use Graphical Analysis or other software to create the graph using the instructions below At a frequency of f 1 2zRC compare the ratio of the output and input voltages to the predicted ratio Vout Vin 0 707 b Phase Response Use the same circuit as above Measure the phase shift of the voltage across the capacitor relative to the input voltage from the oscillator for the same frequency sequence as for the amplitude response above 1 Record your data with columns for f Hz err
96. put voltage the chip will be destroyed if you exceed its maximum input voltage rating which is about 15 V Vary the input voltage from V to 5 V and record Vin at the 8 levels where the three most significant bits of digital output change from LO to HI Present your results in the form of a table Using the function generator produce a triangle wave or sine wave varying from 0 V to 5 V at approximately 0 1 Hz and apply this signal to the input Watch the LEDs as they change and be sure that you understand why they change as they do 141 R 10k MWW C 0 001 uF 1 CS 20 5V 2 RD CLKR 19 LSB V 3 WR DBO 18 4 CLK IN 17 analog input 5 INTR 16 6 Vin 15 digital output 7 Vin 14 ey 8 A GND 13 9 V REF 12 2s MSB 10 D GND X 3k ADC 0804LCN note grounds C2 0 01 uF n analog gnd Test circuit for the ADC 0804 analog to digital converter Use the GND on your prototyping board as both the analog and digital grounds The manufacturer designed the chip so that it can be used with two separate grounds if desired to reduce noise Here we will not use this feature The purpose of C2 is merely to reduce noise in the voltage divider s output it is not a critical component 142 5 Using sensors There are several ways to detect temperature As is often the case a specialized integrated circuit is a good solution Here you will test the LM35DZ Features e Calibrated dire
97. r this zener diode section is the next choice for omission Zener diodes can be used as a simple voltage regulator to establish a reference voltage source for non critical applications CAUTION Zener diodes are very easy to burn up if you make a goof in wiring them up Remove the 3 terminal regulator and its accompanying two capacitors 53 Verify that your Zener diode has a zener voltage that is appropriate for your transformer e g 6 3 V zener for an 8 V transformer Assume the Zener has a power rating of 0 4 W in either case Add a Zener diode across the output of the PI filtered power supply you built in part 3b as shown in Figure 3 6 100 100 Figure 3 6 Pi filter with Zener diode voltage regulator a Calculations Before you power up your circuit do the following i Determine the maximum Zener current from the power rating Z max P g ii Determine the total current through the 91 Q resistor This current is the sum of the Zener current 7 Z and the load current 7 L Check whether it exceeds because there must then be a minimum load 17 max current to prevent overloading the Zener This will imply a maximum load resistance b Measurements i Output voltage Power up your circuit Measure the voltage across the load resistance CAUTION in the next step to protect the resistor substitution box always keep 100 O switched in while you adjust the other scales
98. r a decimal which we will not use e Note 2 the LED display is common anode This means that all the anodes of the seven LEDS are connected together like this Ltt 4 CEL a Counting 7 2k Write a copy of Table 9 1 Check off each state 0 through 9 to confirm that the LED outputs D C B amp A of the counter are properly indicated by the display 125 b Current consumption Use your multimeter in the dc current mode to measure the current from the common anode to 5 V How much current is consumed by the LED display when the display reads 1 and when it reads 8 Note that LED displays are power hungry devices 45V e 74LS47 anode GND A B C D BCD inputs LSD3222 XX 7 segment common anode LED top view 14 NC 13 b note this LED display does not 12 NC actually have 14 leads but the package is shaped like a 14 pin DIP with some leads missing Missing leads are indicated here as NC 11 g 10 c decimal 9 right decimal 8 d 126 6 Latch Used for Switch De Bouncing Note to instructor this circuit must be used with one of the counter circuits above It is possible to use either the binary counter or the decade counter An ordinary mechanical switch bounces several times when it opens or closes This means that it opens and closes several times on a time scale of about 100 s before reaching its final st
99. rator gnd Adjust the pulse generator to produce its maximum output voltage and maximum period choosing a square wave output with a long period of 1s or more so that you can observe both the lamp and waveform simultaneously Observe the collector voltage waveform on an oscilloscope with DC input coupling and the time division adjusted to a long time Verify that the lamp is turned on and off periodically Print the oscilloscope display and mark the waveform indicating when the lamp is on and off Measure the period using the oscilloscope 69 a Calculation Measure the component values Then calculate the bias on the base the potential at the emitter assuming an 0 6 V B E drop b Experiment CAUTION In using the current measurement function of the multimeter start at the highest possible range Using the 12 V power supply built into your prototyping board connect the circuit shown in Figure 4 10 For the load resistor use a resistor substitution box set to 2 kQ to begin i comparison to calculated values Measure and compare to the values calculated above the bias on the base the potential at the emitter ii current vs load resistance Vary RL from 100 to 2 in 100 increments Make a table of current vs load resistance iii compliance Determine the range of load over which the current remains constant to 1096 Compare this result to your result in La
100. re 2 2 Tip Sometimes it is hard to get anything to show on the scope In that case follow this procedure set trigger to AUTO DC COUPLING CH1 set horizontal mode to A set vertical mode to BOTH set sweep speed to ms div CAL MAGNIFIER OFF set vertical coupling to ground turn up intensity wiggle vertical position until a horizontal line appears set vertical coupling to AC or DC 20 Signal output SYNC output lt labeled TTL CMOS BK4017 Function Generator 2 labeled TRIGGER Signal output _ SYNC output QVO LNdLNO ioo NU9N C indie H3991H1L 83991H1 iy cy oe A923 LIS440 H3INH3A S HLOIM 3S1Nd S Up use 318n0Q 3s1nd H3INH3A H3INH3A W3INH3A 5 351 vo z o l OOb ZO WOS 5 wy uz H3INH3A GQOIH3d 3S1Nd ZH S O os 001 A 3anilidWV QHUVMOVd 1131M M 3H HOIVH3N39 357109 SELOS 22 TA Instructions Before the students begin this lab demonstrate the following tricks for using an analog oscilloscope Checking trace rotation Adjust the intensity as low as practical so that the trace is a thin curve Use GND coupling to produce what should be a horizontal line Use the vertical position to move the curve to the middle of the display Verify that the trace is aligned with a horizontal g
101. responds to a 3 dB drop in gain Measure the input amplitude that results in clipping with a 3 dB reduction of the output as compared to the ideal output amplitude What is the output amplitude as a ratio of Vcc when clipping occurs at this level 90 c Frequency response i roll off frequency For the circuit with R2 22 k vary the frequency from a low value 100 Hz upward to find the frequency at which the gain drops by 3 dB Compare to the value given by Figure 4 31 in Horowitz amp Hill 2 Edition ii graph of frequency response Forthe circuit with R2 100 k measure the gain Ay at the logarithmically spaced frequencies of 100 Hz 300 Hz 1 KHz 3 kHz 1 MHz 3 MHz Repeat for R2 10k Plot your results on a log log graph Also show on this graph the theoretical gan lAyl R2 R Note that high gain is achieved at the expense of frequency bandwidth 2 Voltage Follower Unity Gain Non Inverting Amp The circuit in Figure 7 4 has a voltage gain of unity but a very high current gain a Input impedance Usea 5 resistor in series with the function generator at the input to measure the input impedance If it is too high to measure report it as Zj gt gt 5 MQ out 5MO source for measuring Zin voltage follower Figure 7 4 Unity gain non inverting amplifier Voltage Follower 91 3 Summing Amp Note This circuit is similar to one in
102. ridline that is shown permanently on the display If not aligned the scope requires using a small screwdriver to adjust the trace rotation this is required for approximately one out of ten oscilloscopes each year Measuring amplitude Adjust the intensity as low as practical so that the trace is a thin curve Adjust the vertical scale so that the waveform fills most of the display area Use the GND coupling to adjust the zero then the AC or DC coupling to make the measurement Adjust the horizontal position so that the peak or trough of the waveform coincides with the vertical line that has fine tick marks Adjust the time scale so that the peak has an appropriate width so that you can accurately find its maximum typically this will require that you see about two complete oscillations in the horizontal direction Use the second trace other input channel with a GND input to make a cursor as an optional aide in measuring the waveform s height Measuring time Adjust the vertical scale to overfill it by a significant amount so that the waveform looks like almost straight vertical lines then look for zero crossings Use the lowest practical intensity Adjust the horizontal position so that one of the zero crossings occurs on a major division of the horizontal scale Choose an appropriate time scale for best resolution in measuring the time typically about 1 5 or 2 complete oscillations displayed 23 PRELAB
103. switch for example Logic Switch A on the prototyping board as a manually operated clock 116 IN shift register Watch all the states Observe that the input is shifted to the right once each clock cycle Draw a timing diagram showing the four D inputs the final output and the clock The 195 4 Bit Shift Register Shift Registers use a series of D flip flops with the output of one flip flop connected to the input of the next It accepts both series and parallel inputs and produces both series and parallel outputs Thus the 195 can be used to convert series input to parallel output and vice versa 117 Connect the 74LS195 to data Switches for inputs A B C D Logic Switches for inputs SH LD and CLK and LEDs to indicate outputs QA QB QC QD INPUTS OUTPUTS see note state IND INC INg INA CLK SH Op Qc IC pin 7 6 5 4 10 9 12 13 14 15 board SW1 SW2 SW3 SW4 A B LED1 LED2 LED3 LED4 You will also use inputs J and K which you will connect as shown with a wire to short the two inputs n and a 150 or 200 Q resistor to connect to either 5V or 1 GND LWA 2J TA note 2015 the above instruction has changed 3K please test the instruction and report to Prof Goree 4 a Clearing A shift register is a memory device with a state output values QA through QD that depends on previous history However when it is first turned on the state of its memory is unpredictable
104. t 0 01 uF 4 7 uF for 3 term regulator 3 terminal regulator 78L05 in TO 92 package for 3 term regulator TO 92 package 1N914 signal diode Power diode 39 PRELAB Identify all the formulas you will need in this Lab Identify a type of connector you should not connect to a power diode to avoid melting it What will happen if you connect a diode directly across the two terminals of a power supply without a series resistor For the measurement of current how must a multimeter be connected differently as compared to the measurement of voltage 40 PROCEDURE i Ohmmeter Check of Diode 0 0 You will need a multimeter to confirm the polarity of a diode You don t need to report your results here in your lab report Use a magnifying glass to read the part numbers of your diodes and to distinguish the signal zener and power diodes Look at your multimeter to see what special features it has It might have a diode check feature as shown by the symbol If it has one depending on the model the display might indicate the diode drop voltage if the diode is not damaged Confirm the PN polarity of a signal diode these are smaller than the power diodes Look at the markings on the diode to see how they show the polarity Repeat the diode tests above using a power diode Note that for a multimeter check to work the multimeter must apply a voltage of at least 0 5 Volt between its two l
105. t application so you use signal diodes not current diodes Connect the input of this circuit to the function generator with a sine wave at 10 kHz Check that the 20 dB attenuator switch on the function generator is not activated 46 Setup the oscilloscope to show the input and output waveforms Use DC input coupling on the oscilloscope Connect three grounds together the ground of the 5 V power supply the ground of the function generator and the ground of the oscilloscope Adjust the sine wave amplitude so that you can see a clamped output Print the waveforms for the input and output of the clamp circuit If you can see that the clamped voltage is not quite flat then you can see the effect of the diode s non zero impedance in conduction From your observation explain in one or two sentences what the clamp circuit is useful for in 1k out Diode Clamp 5V 3 Power Supply Rectifying Circuits a Half Wave Rectification Setup the circuit as sketched here For this part ignore the center tap CT terminal on the transformer if any You are building a power supply so use power diodes rated at 1 W not the little signal diodes For the load use a 1 kQ resistor or a resistor substitution box set for 1k Scope Input 1 PRI SEC Scope Input 2 8 VAC RL BS Scope Ground 110 VAC variac transformer 47 Caution do not use the insulated mini grabber connectors to co
106. t perform propagation of errors analysis 1X TO THE INSTRUCTOR HOW ONE CAN USE THIS MANUAL This manual is intended for a one semester course The instructor probably will skip some experiments or parts of experiments due to lack of time The first few experiments analog circuits will challenge the student the most One option is to skip some of the Labs and then finish with a project This project is a circuit invented by the student it requires about four weeks The student must begin planning a project several weeks before this four week period begins TO THE TA Before the students do their experiments you must e do the experiment yourself e inventory parts to be sure they are all available e set up each lab table e before the first lab check batteries including those in multimeters If enough parts are available leave your setup in working order for students to examine when they have difficulty You will need to schedule additional time in the lab to accommodate students who are unable to complete their work in 3 hours Students need their graded lab reports within a week of handing them to you If you take longer to grade them students will not know whether they were writing their report as expected or whether they are omitting required information or spending too much time on unnecessary efforts in writing the report Mark your copy of the lab manual with the word EDIT to indicate changes that need t
107. t the output of the comparator changes when you block unblock room lights from hitting the photocell Report the values you chose for the resistor and the power supply voltage for the voltage divider 99 Lab 8 Digital Gates REFERENCE Horowitz and Hill Sections 8 01 8 13 INTRODUCTION Digital devices are basically electronic switches that use two states or logic levels TTL and CMOS are two families of digital circuits Most commonly they are powered by a 5 V power supply although CMOS is sometimes used with 12 V These are integrated circuits i e ICs or chips A digital signal is either ON or OFF state other names for the state TTL CMOS ON HI 1 TRUE 3 0 5 5 V 345 5 5 V Or 845 32 5 V OFF LO 0 FALSE 0 5 1 5 V 0 5 1 5 V Digital ICs called gates perform arithmetic and logical operations one input NOT inverter two or more inputs OR AND NOR NAND XOR Exclusive OR On 14 pin logic chips usually pin 14 is Vcc 5V and pin 7 is ground We will try out these devices and their truth tables then combine them to perform more complicated logical operations We will also test a half adder which perform the arithmetic operation of addition and a multiplexer Copyright 2015 John A Goree Edited by John Goree 5 Jan 2015 EQUIPMENT Lab supplies Prototyping board Power supply Digital multimeter Student kits Wire kits Resistors 220 Q 1 LEDs
108. t will stop working due to loading the power supply Some circuits that involve large currents that are not DC currents for example an LED display or a 555 timer with a large capacitor will cause the power supply voltage to droop momentarily and this can cause errors in logic chips elsewhere in the circuit To avoid this place an electrolytic capacitor a few microfarads across the power supply leads on your prototyping board and locate this capacitor physically near the subcircuit e g the 555 timer or LED display that demands a large current If you use a 9 Volt battery you can reduce the voltage to 5 VDC using the 3 pin voltage regulator from one of the labs in this manual 148 Checklist for Project Grading At the end of your project you will Present a schematic diagram e label every part part number and function if it is a chip e identify function of switches LED indicators etc o e g reset power Present a list of specifications e atleast 3 numbers e example o frequency bandwidth Hz 3 dB flatness o maxinput voltage V o inputimpedance Q e identify whether measured or computed o measured is better e include error estimate and units Demonstrate how your circuit works e plan how to show it in 5 minutes e start by showing the schematic diagram and disclosing which features are not your own design e incase it doesn t entirely work o demonstrate that part of it works o hop
109. tainty is 0 005 x 5 30 1 x 0 01 0 0365 Volt 4 Rounding to 0 04 your result is 5 30 0 04 Volt Vil Agilent 34410A Multimeter Accuracy Specifications of reading of range Function Range Frequency 24 Hour Test Current or Tcal 1 C Burden Voltage DC Voltage 100 0000 mV 0 0030 0 0030 1 000000 V 0 0020 0 0006 10 00000 V 0 0015 0 0004 100 0000 V 0 0020 0 0006 1000 000 v 0 0020 0 0006 True RMS 100 0000 mV 3Hz 5Hz 0 50 0 02 AC Voltage to 750 000 V 5 Hz 10 Hz 0 10 0 02 10 Hz 20 kHz 0 02 0 02 20 kHz 50 kHz 0 05 4 0 04 50 kHz 100 kHz 0 20 0 08 100 kHz 300 kHz 1 00 0 50 Resistance 100 0000 Q 1mA 0 0030 0 0030 1 000000 1mA 0 0020 0 0005 10 00000 kQ 100 pA 0 0020 0 0005 100 0000 kQ 10 pA 0 0020 0 0005 1 000000 MQ 5 pA 0 0020 0 0010 10 00000 MQ 500 nA 0 0100 0 0010 100 0000 500 nA 10 M 0 200 0 001 1 000000 GQ 500 nA 10 M 2 000 0 001 DC Current 100 0000 pA 0 03V 0 010 0 020 1 000000 mA 0 3 V 0 007 0 006 10 00000 mA 0 03V 0 007 0 020 100 0000 mA 03 v 0 010 0 004 1 000000 A 08 V 0 050 0 006 3 000000 A 20 V 0 100 0 020 True RMS 100 0000 pA to 3 Hz 5 kHz 0 10 0 04 AC Current 3 00000 A 5 kHz 10 kHz 0 20 0 04 Frequency 100 mV to 3Hz 5Hz 0 070 0 000 or Period 750 V 5 Hz 10 Hz 0 040 0 000 10 Hz 40 Hz 0 020 0 000 40 Hz 300 kHz 0 005 0 000 Capacitance 1 0000 nF 500 nA 0 50 0 50 1
110. the 411 it is different Use the power supplies of the prototyping boarding 12 V power supply for analog 5 V power supply for digital 2 a ibd Adjust the function generator to provide an 8 V peak peak sine wave at 1 5 kHz Observe the digital output of the comparator on CH1 of your oscilloscope and the sine wave analog input on CH2 Trigger the scope on CH1 using the falling edge with 100 us division for the horizontal scale 97 Record the oscilloscope display when the threshold is set to the following two values 3 V 1 OV Discuss qualitatively how the output waveform changes states in response to e Up going analog input voltage e Down going analog input voltage Now zoom in to the down going change in digital output voltage using a 250 nsec div on the oscilloscope s horizontal scale Record the oscilloscope display showing the ringing or oscillations present in the digital output with a typical characteristic time of 200 nsec Now connect a 100k resistor between output pin 7 and the non inverting input pin 2 of the comparator This provides positive feedback Record the waveform Discuss whether the undesired oscillations are diminished by using positive feedback and if so whether the effect is a strong one 8 Using sensors There are several ways to detect light e Here you will use a photocell which is a simple
111. to indicate zero current it may have a blown fuse CAUTION In this step to protect the resistor substitution box always keep 50 or 100 Q switched in while you adjust the other scales This precaution will keep you from accidentally setting the resistor substitution box to zero resistance CAUTION As always measure current beginning with the meter set to the highest scale 52 22 TO 92 package TO 220 package Set Rr to about 10 and vary it downward Note the load resistance at which ripple begins to appear What current value does this correspond to This is the maximum regulated current e Thermal protection Continue to decrease the load resistance Does the output of the regulator shut down when the current exceeds a certain threshold This is the current limit of your regulator To work this shut down test requires using a regulator in the TO 92 package don t use a larger package like TO 220 LM78MOSCT for this lab it won t shut down under these conditions An advantage of these three terminal regulators is the shutdown feature Another alternative for voltage regulation is the zener diode in the next experiment but zeners do not have thermal protection so you must be careful to select the right one and use it within its design parameters 6 Voltage Regulation with Zener Diodes TA note Some TAs omit the SCR circuit to save time If it is necessary to reduce the time furthe
112. two terminal sensor that acts like a resistor with a resistance that diminishes as the light level is increased It is not a linear sensor so its use if often limited to electric eye applications that require detecting whether conditions are dark for example to turn street lights on and off e Ifyou needed to measure light intensity over a continuous scale you would choose a different sensor with a linear response to light intensity such as a photodiode or photomultiplier tube NSL 4522 CdS Photocell specifications from Silonex datasheet Raark min 1M minimum R 1 foot candle 18 6 k 4 40 R 100 foot candle 400 typical 98 Design a simple voltage divider to replace the function generator in the comparator circuit above so that the comparator circuit s output voltage will change when you cover the sensor with your hand to block the room lights e The voltage divider should consist of the photocell and a suitable fixed resistor and it should be connected to a suitable power supply e It may be helpful to know that indoor room lighting is typically in the range of 10 100 foot candles Whether this circuit works will depend on your choice for the voltage divider resistance power supply and threshold voltage for the comparator You must decide on your own what values to use for the resistance and what to use for the voltage divider s power supply e After designing the circuit Verify tha
113. umns C B A and Y Repeat for D1 LO 110 Operating the circuit with D1 high and then D1 low verify the two truth tables you predicted above you can indicate a successful test with a checkmark to the right of a row a b A AB B B c d Figure 8 2 Circuits using NOR gates 111 i Figure 8 3 Different realizations of XOR gt 5 out C Figure 8 4 Half adder 112 Lab 9 Flip Flops Shift Registers Counters Decoders 7 Segment Display REFERENCE Horowitz and Hill Sections 8 16 8 26 Section 9 10 LED display Section 9 04 De bouncer INTRODUCTION In this lab we study two versions of the Flip Flop bistable multivibrator Then we test some counters and learn about BCD binary coded decimal Next we take the BCD output produced by the decade counter and convert it with a decoder driver to power a 7 segment LED display After building a counter we will use it to demonstrate how a switch de bouncer works Finally we try out a BCD to decimal converter You will look up a few items in data sheets to learn how to find information for chips EQUIPMENT Lab supplies Prototyping board Digital Oscilloscope Pulse Generator Digital Multimeter Switch SPDT momentary contact with wires attached for de bounce Student kits Wire kit Digital ICs TTL LS or CMOS HC 7400 Quad NAND 7442 BCD to Decimal Decoder 7447 BCD to 7 segment decoder driver
114. unction generator to produce a sine wave of about 1 to 2 Volt amplitude a frequency of about 100 Hz and no DC offset Verify that the sweep INT EXT switch is in the EXT position to disable the sweep feature of this instrument Seta multimeter to the AC voltage function Connect it to the function generator s output Adjust the display intensity as low as practical so that the trace is a thin line Measure the peak to peak AC voltage using the oscilloscope Calculate the RMS value of the voltage Compare the AC voltage oscilloscope measurements to those on the digital multimeter Report the measurement uncertainty error values Which is more precise the meter or the oscilloscope c Sweeping the frequency no response necessary for lab report Learn to use the frequency sweep feature of your function generator Sweeping means that the frequency is ramped up with time in a way that repeats itself Observe this by depressing the INT button to enable the sweep 26 Observe the waveform Try different adjustments of the TIME and WIDTH knobs for sweep to see their effect When you are done return the generator to its normal non sweep operation by pressing the INT button so that it is out not in d AC and DC coupling Make sure the oscilloscope coupling is set to DC Set the function generator frequency to about 10 kHz Turn on the offset voltage on the function generator an
115. usted too high or too low there is a loss of triggering and this can casuse the displayed waveform to be unstable in the horizontal direction Next repeat with NORM rather than AUTO trigger In this mode the scope will not update the display unless there is a valid trigger event unlike the AUTO mode which will trigger occasionally even when there s no valid trigger event just so that you can see at least something on the display Push the MEASURE button and view the menu Toggle the Type setting to measure the peak to peak voltage and the frequency of the waveform Then adjust the TIME DIV knob so that less than one full oscillation is shown and notice how the scope is unable to measure frequency 44 0 5 Digital Oscilloscope Skills Use the function generator to apply a sine wave of approximately 1 2 1 8 volts amplitude and approximately 1 kHz frequency to one of the oscilloscope inputs Using the MEASURE button measure the amplitude and period of the waveform Compute the uncertainty of the amplitude and the uncertainty of the period e Do this using specifications from the oscilloscope manufacturer s user manual For the TDS 1000 or 2000 series oscilloscope see pp 155 156 e To compute the uncertainty of the period you will require the sample interval which is the reciprocal of the samples per sec this parameter depends on the tim div setting see the table on pp 22 23 e Note t
116. void damaging your multimeter In the current function Never connect a current meter directly to a voltage source like 110 VAC or a battery Without a resistor to limit the current this would destroy the meter or at least blow a fuse inside the meter In the resistance function Never connect the multimeter to a resistor that is part of a circuit Use it only to measure the value of a loose resistor 6 Current a Measured values 560 Measure the actual value of the resistor shown in Fig 1 8 Throughout this course always measure your resistor values before assembling the circuit 15V Z b Comparison to predicted values Figure 1 8 Wire up the circuit in Figure 1 8 Set the function switch to the maximum current scale 2 A and connect the meter into the circuit Note that for current measurements the meter is in series with the other elements of the circuit This is different from voltage measurements where it is in parallel 11 Compare the measured value with the value of current you would calculate using the measured values of voltage and resistance Do they agree within the error value range Explain any discrepancy 7 Current Source Connect a 1 5 V battery and a large valued resistor 3 3 kQ or higher to make a current source For a load resistor use the resistor substitution box choosing values ranging from 0 1 to 2 0 times the value of the large resistor as shown in Fi
117. w strips that look like this note some boards have only two strips not four as shown here 412V 5 GND 12V oO Insert the ICs carefully to avoid bending their leads into the wider strips like this Inverting amplifier To measure the amplitude of a sine wave measure peak to peak and divide by two Setup the oscilloscope to show a dual trace one for the input of the op amp and one for the output Use DC input coupling Set up the function generator to produce 89 a sine wave with an amplitude 0 2 V and frequency 1 kHz Use the 20 dB button on your function generator if necessary to reduce your function generator output to such a low amplitude Make sure that the grounds of the function generator oscilloscope and prototyping board are somehow connected Measure the values of your resistors then using the prototyping board wire up the inverting amplifier shown in Figure 7 3 H2 1k 10k 22k H1 1k in O out Figure 7 3 Inverting amplifier a Gain i Measure the gain Ay for R2 1k 10 k and 22 k ii Using measured values of R2 and Rj compare to Ay 2 iii Verify that the amplifier inverts b Saturation For the circuit with R2 22 increase the input signal amplitude to observe clipping Calculate the ratio Vou Vin that cor

Lab Manual 2015 - John A. Goree

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