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PK-101 REV

1. The power of a moving object Morse A code used to send messages with long or short transmit bursts type of digital circuit which gives a HIGH output if some of its inputs LOW NOR Gate A type of digital circuit which gives a HIGH output if none of its inputs are HIGH NOT Gate A type of digital circuit whose output is opposite its input NPN Negative Positive Negative a type of transistor construction Ohm s Law The relationship between voltage current and resistance Ohm Q The unit of measure for resistance OR Gate A type of digital circuit which gives a HIGH output if any of its inputs are HIGH Oscillator A circuit that uses feedback to generate an AC output Parallel When several electrical components are connected between the same points in the circuit Pico p one A prefix used in the metric system It means a millionth of a millionth 0 000 000 000 001 of something Pitch dees The musical term for frequency 70 Primary The larger of the two coils in a transformer Printed Circuit Board A board used for mounting electrical components Components are connected using metal traces printed on the board instead of wires Receiver The device which is receiving a message usually with radio
2. A sub atomic particle that has an electrical charge 69 Electronics The science of electricity and its applications Emitter The output of an NPN bipolar junction transistor put a message into a format which is easier to transmit Farad The unit of measure for capacitance Feedback To adjust the input to something based on what its output is doing Flip Flop A type of transistor configuration is which the output changes every time it receives an input pulse Forward Biased The state of a diode when current is flowing through it Frequency The rate at which something repeats Friction The rubbing of one object against another It generates heat Gallium Arsenide A chemical element that is used as a semiconductor Generator A device which uses steam or water pressure to move a magnet near a wire creating an electric current in the wire Germanium A chemical element that is used as a semiconductor common term for the OV or side of a battery or generator Henry The unit of measure for Inductance Inductance The ability of a wire to create an induced vol
3. PUMP 12 EXPERIMENT 3 RESISTORS IN SERIES Remove the resistors used in Experiment 2 the other parts are used here Insert the new parts according to the Wiring Checklist and press the switch The LED is on but is very dim this will be easier to see if you wrap your hand near the LED to keep the room lights from shining on it Take a look at the schematic There is a low 3 3kQ resistor and a high 100kQ resistor in series one after another Since the LED is dimly lit we know that the larger 100kQ must be controlling the current You can think of this as where two sections of the pipe are filled with rock if one section is much longer than the other then it controls the water flow If you had several rock sections of different lengths then it is easy to see that these would add together as if they were one longer section The total length is what matters not how many sections the rock is split into The same is true in electronics resistors in series add together to increase the total resistance for the circuit In our circuit the 3 3kO and 100kQ resistors add up to 103 3kQ To demonstrate this remove the 100kQ resistor and insert the 10kO in the same holes press the switch the LED should be easy to see now total resistance is now only 13 3kO Next remove the 10 resistor and replace it with the 1kO The LED is now bright but not as bright as when you used the 1kQ in Experiment 1 Why Because now the 3 3kQ is t
4. Resistance The electrical friction between an electric current and the material it is flowing through the loss of energy from electrons as they move between atoms of the material Resistor Components used to control the flow of electricity in a circuit They are made of carbon Resistor Transistor Logic RTL A type of circuit arrangement used to construct digital gates Reverse Biased When there is a voltage in the direction of high resistance across a diode Saturation The state of a transistor when the circuit resistances not the transistor itself are limiting the current Schematic A drawing of an electrical circuit that uses symbols for all the components The smaller of the two coils a transformer Semiconductor A material that has more resistance than conductors but less than insulators It is used to construct diodes transistors and integrated circuits When electrical components are connected one after the other Short Circuit When wires from different parts of a circuit or different circuits connect accidentally Silicon The chemical element most commonly used as a semiconductor Solder A tin lead metal that becomes a liquid whe
5. sound using the variable resistor If you find it inconvenient to turn the VR knob while pressing the switch then just connect a wire across the switch Do you know how this circuit works It s basically the same as the last circuit except for the 10uF capacitor which instantly charges up when you press the switch and then discharges by powering the circuit for a few seconds after you release the switch You can experiment with changing component values if you like TRANSFORMER SPEAKER E ft LLL T T EXPERIMENT 35 ELECTRONIC NOISEMAKER Connect the circuit connecting the battery last since it will turn the circuit on Press the switch several times quickly Then turn the variable resistor knob to change the frequency of the sounds Do you understand what s happening when you press the switch You increase the oscillator capacitance by putting the 0 005uF in parallel with the 0 047uF and this lowers the oscillator frequency As usual you can experiment with changing component values if you like TRANSFORMER SPEAKER 005uF EHEHE LLL TI RENEE LET T ss Ltt yt e PSs CU EE tT inf TTA 51 EXPERIMENT 36 DRAWING RESISTORS You need some more parts to do this experiment so you re going to draw them Take a pencil No 2 lead is best but other types will also work SHARPEN IT and fill in the 4 rectangles you see below You
6. Elenco Electronics Inc 150 W Carpenter Avenue Wheeling IL 60090 847 541 3800 http www elenco com e mail elenco elenco com Fax 847 520 0085
7. LEDs diode and transformer as per the guides Be sure you have a good 9V battery If not sure then try a new battery Be sure you understand how to read the resistor color code so that you use the right value parts e Be sure you understand which breadboard holes are connected to which Contact Elenco Electronics Inc our address phone website is on the back of this booklet if you further assistance DO NOT contact your place of purchase as they will not be able to help you FOR FURTHER READING all of these are available through Elenco Electronics Inc Van Valkenburgh Nooger and Neville 1993 Basic Electricity Sams 61041 Rezurch 1996 Electronics Terminology Sams 67013 Johnson J R 1994 Schematic Diagrams Sams 61059 Kamichik S 1996 Digital Electronics Sams 61075 68 DEFINITION OF TERMS Most of these are introduced and explained during the experiments AC Common abbreviation for alternating current Alternating Current A current that is constantly changing Amp ies Shortened name for ampere Ampere The unit of measure for electric current Commonly shortened to amp Amplitude Strength or level of something Analogy A similarity in some ways AND Gate A type of digital circuit which gives a HIGH output only if all of its inputs are HIGH Astable Multivibrator A type of transis
8. along the drawing and see how the sound changes Making the drawn resistors longer should increase the resistance resistors in series or longer water pipes while making them wider should reduce the resistance resistors in parallel or larger water pipes So all 4 rectangles should produce the same sound though you will see variations due to how thick and evenly you filled in the rectangles and exactly where you touch the wires If your 4 shapes don t sound similar then try improving your drawings Be sure to wash your hands after this test unless you re going on to Experiment 37 now 52 4 gt c m 2 z 4 4 E LONG WIRES SPEAKER LONG LOOSE WIRES 53 EXPERIMENT 37 ELECTRONIC KAZOO Now it s time to make your own music This experiment will use the almost same circuit as the last one so there is no schematic or Wiring Checklist The only difference is that you will draw a new shape A Kazoo is a musical instrument that is like a one note flute and you change the pitch frequency of the sound by moving a plunger up and down inside a tube As before take a pencil No 2 lead is best but other types will also work SHARPEN IT again and fill in the shape you see below For best results SHARPEN IT again place a hard flat surface between this page and the rest of this booklet while you are drawing Press hard but don t rip the paper Fill in each several times to be sure you have a thick even layer
9. be used as a timer You might use a circuit like this with your microwave oven You press the switch to turn the oven on and have a knob the variable resistor to adjust how long the oven stays on it then shuts off automatically NPN NPN LEF T5 RIGHT LLL 5 j LII TT J EXPERIMENT 43 ALARM WITH SHUT OFF TIMER Let s demonstrate a use for the timer circuit you just built by combining it with Experiment 30 the Alarm Connect the circuit noting that the transistor bases and transformer signals are not connected although their wires cross in the schematic Connect the alarm trip wire and then connect the battery wire to turn the circuit on Press the switch once Now disconnect the trip wire to activate the alarm The alarm stays on for a few seconds and then goes off Re connect the trip wire and press the switch to reset the alarm and timer If you only re connect the trip wire without resetting the timer then the alarm won t work the next time You could use a circuit like this where you get lots of false alarms and you want to shut off the alarm before the battery gets weak Automobile alarms for example get lots of false alarms TRANSFDRMER NPN RIGHT NPN CENTER TRIP WIRE 60 EXPERIMENT 44 THE FLIP FLOP This circuit is yet another variation of the basic multivibrator configuration Connect the circuit One LED will be on the other off Take the lo
10. but is typically a few hundred kilohms Think of this circuit as a touch lamp since when you touch it the LED lights You may have seen such a lamp in the store or already have one in your home LOOSE WIRE switch is left unconnected for future experiments EXPERIMENT 21 THE ONE FINGER TOUCH LAMP Actually the touch lamps you see in stores only need to be touched by one finger to light not two So let s see if we can improve the last circuit to only need one finger Connect the circuit the only changes from the last experiment are the addition of the 1kQ and 10kQ resistors These two resistors plug into adjacent but not connected holes g10 and g11 Wet a large area of one of your fingers and touch it to the resistor metal coming out of these two holes at the same time the LED lights To make it easier for one finger to touch the two contacts touch lamps or other touch devices will have the metal contacts interweaved as shown below and will also be more sensitive so that you don t have to wet your finger to make good contact BATTERY TRANSISTOR CONNECTION CONNECTION This circuit is still different from the touch lamps sold in stores because the LED goes dark if you remove your finger from it We need a way of remembering when you ve touched the lamp to turn it on or off we need a memory and we ll show you one in Experiment 45 33 EXPERIMENT 22 THE VOLTMETER Make sure you have a strong 9V battery for this e
11. coils and transformers only apply to AC alternating current For DC inductors act as wires with no special properties and transformers are just two separate unconnected wires TEST YOUR KNOWLEDGE 2 1 A diode has very high resistance when it is biased 2 Diodes whose turn on energy is so high that light is generated are known as 3 The transistor is best thought of as a current 4 An circuit is one that might have many resistors diodes capacitors and transistors on a single piece of silicon 5 A transistor is when the circuit resistances not the transistor itself are limiting the transistors collector current 6 Inductors have low resistance to current and high resistance to current 7 Adding inductors in parallel the inductance while adding inductors in series the inductance 8 Electrons not only have electric properties but also properties 9 Wrapping a coil around an iron bar the inductance 10 If the second coil in a transformer has half as many turns as the first coil then the second coil will have as much alternating current as the first coil Answers are on page 3 41 EXPERIMENT 27 THE MAGNETIC BRIDGE Connect the circuit and press the switch several times LED left blinks when the switch is pressed and LED right blinks when the switch is released Although the LED may blink in the same manner as the last experiment the method is quite different There is no wire connection across the transformer
12. its DC resistance is very high When you press the switch there is a sudden surge of current AC through the inductor that magnetically creates a current on the other side of the transformer lighting LED left The current from the battery quickly settles after the initial surge becomes DC and the magnetic induction stops because the current is no longer changing hence no current flows through the LED even though there is current on the battery side of the transformer When you release the switch the sudden drop in current through the transformer magnetically creates a new current on the other side of the transformer but this time in the opposite direction so LED right lights instead of LED left Again this current is brief and the LED only blinks The transformer has many more turns more inductance on the LED side than on the battery side this boosts the voltage to the LEDs though it also lowers the current If you reverse the transformer then you won t have enough voltage to turn on the LEDs You might think of a transformer as a magnetic bridge in electronics since we use magnetism to cross a barrier that electricity cannot cross by itself Transformers are mainly used for isolating and buffering different circuits from each other and you will soon see some examples of this TRANSFORMER Primary side has 3 wires while secondary side has only 2 wires Note positions of LED flat sides LED RIGHT gt ev
13. of pencil lead and try to avoid going out of the boundaries Where the shape is just a line draw a thick line and go over it several times The black ink in this manual is an insulator just like paper so you have to write over it with your pencil Shape to be drawn Use a SHARP No 2 pencil draw on a hard surface press hard and fill in several times for best results Take one loose wire and touch it to the widest part of this shape at the upper left Take the other loose wire and touch it just to the right of the first wire You should hear a high pitch sound How do you think the sound will change as you slide the second wire to the right Do it slowly sliding all the way around to the end The sound changes from high frequency to low frequency just like a kazoo Note you may get better electrical contact between the wires and the drawings if you wet the wires with a few drops of water or saliva This circuit is nearly the same as for Experiment 29 Electronic Sound so you can use the notes you took there to estimate what the resistance is at various points along your kazoo Be sure to wash your hands after this test unless you re going on to Experiment 38 now 54 EXPERIMENT 38 ELECTRONIC KEYBOARD This experiment will use the almost same circuit as the last one so there is no schematic or Wiring Checklist The only difference is that you will draw a new shape As before take a pencil No 2 lead is best bu
14. opened If the pressure is to flow to the left then the plate will be pressed against the solid stop and no water will flow Electronic diodes are made from materials called semiconductors so called because they have more resistance than metal conductors but less than insulators Most semiconductors are made of Silicon but Gallium Arsenide and Germanium are also used Their key advantage is that by using special manufacturing processes their resistance is decreased under certain operating conditions The manufacturing processes create two regions of permanent electrical charge quite different from charging a capacitor While the physics of how this works is quite complicated the effect is that once the voltage across the diode exceeds a small turn on level 0 7V for Silicon the resistance of the diode becomes very low in one direction so low in fact that the current flow must be limited by other resistances in the circuit to prevent damage to the diode When the diode is turned on like this we refer to it as being forward biased In the other direction the diode is always a very high resistance we call this reverse biased The schematic symbol shown below indicates that the diode will allow current to flow from left to right but block current flow from right to left Symbol for DIODE EXPERIMENT 12 ONE WAY CURRENT Your PK 101 includes one diode a 1N4148 which is a standard diode widely used in industry Connect the circuit and press th
15. pivot shown here Notice that it includes a check valve that is connected to a lever arm A small amount of base current pushes on the check valve which turns and opens the lever arm But before this base current can start to flow though it must have enough water pressure to overcome the spring in the check valve usually 0 7V If the base pipe is much smaller than the collector and emitter pipes then a small base current Ig flowing in will cause a large collector current 1 to flow in these will combine and exit the device as emitter current lg In transistors the emitter base and collector are different regions of permanent electrical charge producing the effects described above for the lever pivot The properties and uses of transistors may seem confusing at first but will become clear as you proceed through the experiments All but one of the remaining experiments will use the transistor so its importance to electronics should be apparent A key advantage of semiconductors is that several transistors can be manufactured on a single piece of silicon This led to the development of Integrated Circuit IC technology in which careful control of complex manufacturing processes has enabled entire circuits consisting of transistors diodes resistors and capacitors to be constructed on a silicon base Some ICs used in computers now have more than a million transistors on them Spectacular improvements in cost size and reliability have b
16. the alarm will sound This is how professional burglar alarms work although some use beams of light across the doorway or window instead of wire for the trip mechanism The trip wire could also alert your local police station instead of turning on the alarm here This circuit is the same oscillator circuit you just used except that the trip wire was added The trip wire creates a short circuit across the transistor base so no current flows into the base and the transistor stays off Disconnecting the trip wire eliminates the short and the oscillator works normally If you like you can adjust the loudness of the alarm by replacing the 3 3kQ resistor with the variable resistor TRANSFORMER Sd SPEAKER V LONG TRIP WIRE 46 EXPERIMENT 31 MORSE CODE The forerunner of today s telephone system was the telegraph which was widely used in the latter half of the 19th century It only had two states on or off that is transmitting or not transmitting and could not send the range of frequencies contain in human voices or music A code was developed to send information over long distances using this system and a sequence of dots and dashes short or long transmit bursts It was named Morse Code after its inventor It was also used extensively in the early days of radio communications though it isn t in wide use today except in amateur radio ham radio It is sometimes referred to in Hollywood movies especi
17. then the water in the coil will never start moving and the AC constantly changing current will be blocked Coils in electronics follow these same principles a coil will pass DC and block AC Recall from above that a capacitor will block DC but pass AC When determining the response of a circuit to DC inductors are treated as closed switches and capacitors are treated as open switches For the AC response the values of the inductors and capacitors must be considered along with the rate at which the current alternates called the frequency For DC changes to the circuit called transients such as closing the switch to connect a battery to capacitor circuit the circuit response is initially AC and then reverts to DC How do inductors in series and parallel add up You saw in Experiment 26 that changing the connection point on the inductor to reduce the length of the coiled wire reduced LED brightness If you think of this in terms of the coiled hose then it is easy longer hoses will hold more water hence more inductance Two hoses in parallel will result in more water coming out less inductance since the same water pressure applies to each hose This situation should sound familiar since inductances in series and parallel add together just like resistors do For advanced students the mathematical relationship is L represents inductance L Series L4 L2 L4 X Lo L Parallel L4 Lo The inductance is expressed in h
18. value The second ring represents the second digit of the resistor s value The third ring tells you the power of ten to multiply by or the number of zeros to add The final and fourth ring represents the construction tolerance Most resistors have a gold band for a 596 tolerance This means the value of the resistor is guaranteed to be within 596 of the value marked The colors below are used to represent the numbers 0 through 9 lt gt r c m Example of Color Code RED ORANGE VIOLET GOLD 0 1 2 3 4 5 6 7 8 9 27 X 10 000 27 000 with 5 Tolerance Use the color code to check the values of the seven resistors included in your PK 101 and compare to the list below YELLOW VIOLET BROWN GOLD is 470 with 5 tolerance BROWN BLACK RED GOLD is 1 000 or 1 with 5 tolerance ORANGE ORANGE RED GOLD is 3 300 or 3 3 kQ with 5 tolerance BROWN BLACK ORANGE GOLD is 10 000 Q or 10 kQ with 5 tolerance ORANGE ORANGE ORANGE GOLD is 33 000 Q or 33 kQ with 5 tolerance BROWN BLACK YELLOW GOLD is 100 000 Q or 100 kQ with 5 tolerance BROWN BLACK GREEN GOLD is 1 000 000 Q or 1 MQ with 5 tolerance 10 The Variable Resistor We talked about how a switch is used to turn the electricity on and off just like a valve is used to turn the water on and off But there are many times when you want some water but don t need all that the pipe can deliver so you control the
19. will get better results if you place a hard flat surface between this page and the rest of this booklet while you are drawing Press hard but don t rip the paper and fill in each several times to be sure you have a thick even layer of pencil lead and try to avoid going out of the boundaries Shapes to be drawn Use a SHARP No 2 pencil draw on a hard surface press hard and fill in several times for best results Actually your pencils aren t made out of lead anymore although we still call them lead pencils The lead in your pencils is really a form of carbon the same material that resistors are made of So the drawings you just made should act just like the resistors in your Electronic Playground Connect the circuit it s the same basic oscillator circuit you have been using Take the two loose wires and touch them to opposite ends of the smallest rectangle you drew you should hear a sound like an alarm Note you may get better electrical contact between the wires and the drawings if you wet the wires with a few drops of water or saliva What kind of sound do you think you ll get with the other drawings Hint think about how resistors operate in series and parallel combinations or think in terms of the water pipes Now touch the loose wires to opposite ends of the other rectangles you drew you may need to wet the wires again and see if you were right You can also slide one of the wires
20. BASIC ELECTRONIC EXPERIMENTS MODEL PK 101 TRANSFORMS ANY STANDARD BREADBOARD INTO AN ELECTRONIC LEARNING CENTER Perform 50 Experiments In this booklet you will learn The basic principles of electronics How to build circuits using a breadboard How all of the basic electronic components work and how to read their values How to read electronic schematics How to design and troubleshoot basic electronic circuits How to change the performance of electronic circuits by changing component values within the circuit TABLE OF CONTENTS Parts List Page 3 Answers to Quizzes 3 Introduction to Basic Components 4 Experiment 1 The Light Bulb 8 More About Resistors 10 Experiment 2 Brightness Control 12 Experiment 3 Resistors in Series 13 Experiment 4 Parallel Pipes 14 Experiment 5 Comparison of Parallel Currents 15 Experiment 6 Combined Circuit 16 Experiment 7 Water Detector 17 Introduction to Capacitors 18 Experiment 8 Slow Light Bulb 20 Experiment 9 Small Dominates Large 21 Experiment 10 Large Dominates Small 22 Experiment 11 Make Your Own Battery 23 Test Your Knowledge 1 24 Introduction to Diodes 24 Experiment 12 One Way Current 25 Experiment 13 One Way Light Bulbs 26 Introduction to Transistors 27 Experiment 14 The Electronic Switch 28 Experiment 15 The Current Amplifier 28 Experiment 16 The Substitute 29 Experiment 17 Standard Transistor Biasing Circuit 30 Experi
21. Counter Clockwise Opposite the direction in which the hands of a clock rotate Current A measure of how fast electrons are flowing in a wire or how fast water is flowing in a pipe Darlington A transistor configuration which has high current gain and input resistance Common abbreviation for direct current Decode To recover a message Detector A device or circuit which finds something Diaphragm A flexible wall Differential Pair A type of transistor configuration Digital Circuit A wide range of circuits in which all inputs and outputs have only two states such as high low Diode An electronic device that allows current to flow in only one direction Direct Current A current that is constant and not changing Disc A type of capacitor that has low capacitance and is used mostly in high frequency circuits Electric Field The region of electric attraction or repulsion around a constant voltage This is usually associated with the dielectric in a capacitor Electricity A flow of electrons between atoms due to an electrical charge across the material Electrolytic Capacitor A type of capacitor that has high capacitance and is used mostly in low frequency circuits It has polarity markings Electron
22. ECTED AT LEAST ONE VALVE WATER IS ALWAYS CLOSED METER 1 Nr l PUMP 23 TEST YOUR KNOWLEDGE 1 1 are the particles that flow between atoms as part of an electric current 2 A circuit occurs when wires or components from different parts of the circuit accidentally connect 3 A produces electricity using a chemical reaction 4 To decrease the current in a circuit you may decrease the voltage or the resistance 5 Materials which have very high resistance are called and materials which have very low resistance are called 6 Adding resistors in parallel the resistance while adding resistors in series the resistance 7 The electrical resistance of water when salt is dissolved in it 8 Capacitors are components that can store for periods of time 9 Capacitors have low resistance to current and high resistance to current 10 Adding capacitors in parallel the capacitance while adding capacitors in series the capacitance Answers are on page 3 INTRODUCTION TO DIODES The Diode The diode is an electronic device that allows current to flow in only one direction In our water pipe analogy it may be thought of as the check valve shown here Water Tight Pivot Movable Plate The check valve only allows water to flow in one direction to the right in this drawing There is a small spring and if the water pressure exceeds a certain level then the spring will be stretched and the valve
23. Now hold the switch closed with one hand and turn the dial on the variable resistor with the other When the dial is turned to the left the resistance in the circuit is low and the LED is bright because a large current flows As you turn the dial to the right the resistance increases and the LED will become dim just as forcing the water through a section of rocks would slow the water flow and lower the reading on your water meter You may be wondering what the 1kQ resistor is doing in the circuit If you set the dial on the variable resistor for minimum resistance 0Q then Ohm s Law tells us the current will be very large and it might damage the LED think of this as a very powerful water pump overloading a water meter So the 1kQ was put in to limit the current while having little effect on the brightness of the LED Now remove the wire from c14 and connect it to c16 Do you know what will happen now Close the switch and you will see that as you turn the dial from the left to the right the LED goes from very dim to very bright the opposite of when connected to c14 because you are decreasing the resistance between the center and right pins Now remove the 1kQ resistor from hole j15 and insert it into hole c14 the other end stays in j5 What do you think will happen Close the switch and turn the dial on the variable resistor The LED is dim and turning the resistor dial won t make it any brighter As discussed above the resistance between th
24. STAND CAN WITHSTAND LOW PRESSURE HIGH PRESSURE HIGH PRESSURE SOFT STIFF STIFF RUBBER RUBBER RUBBER 18 Similarly capacitors are described by their capacity for holding electric charge called their Capacitance and their ability to withstand electric pressure voltage without damage Although there are many different types of capacitors made using many different materials their basic construction is the same The wires leads connect to two or more metal plates that are separated by high resistance materials called dielectrics Consiruction of a Capacitor METAL PLATE DIELECTRIC The dielectric is the material that holds the electric charge pressure just like the rubber diaphragm holds the water pressure Some dielectrics may be thought of as stiff rubber and some as soft rubber The capacitance and working voltage of the capacitor is controlled by varying the number and size of metal dielectric layers the thickness of the dielectric layers and the type of dielectric material used Capacitance is expressed in farads F named after Michael Faraday whose work in electromagnetic induction led to the development of today s electric motors and generators or more commonly in microfarads uF millionths of a farad or picofarads pF millionths of a microfarad Almost all capacitors used in electronics vary from 1pF to 1 000uUF Your PK 101 includes two electrolytic 10uF and 100uF and two disc 0 005uF and 0 047uF capacitor
25. TER NPN lt RIGHT gt DIODE 38 EXPERIMENT 26 THE ANTI CAPACITOR Recall that capacitors blocked direct current DC but passed alternating current AC Take a look at Experiment 8 again and remember that it took time to light the LED because you had to charge the capacitor first the capacitor passed the initial current surge through to ground the negative side of the battery but blocked the current once it stabilized forcing it to go through the LED The inductor is the counterpart to this it blocks current surges AC but passes stable currents DC Before explaining the inductor further let s demonstrate it using almost the same circuit as in Experiment 8 We will be using an inductor that is part of the transformer we ll explain more about this later Connect the circuit and press the switch several times The LED will blink once when the switch is pressed and again when it is released Note how this is different from the capacitor when the LED became bright when the switch was pressed and stayed bright until the switch was released The inductor effects are brief so we are using the transistor to amplify the current to the LED and make the inductor s effects easier to see Now remove the wire from hole b46 on the transformer connect it to hole b48 and press the switch a few more times The LED will not blink as brightly now because we are using less inductance TRANSFORMER Primary side has 3 wire
26. TRANSFORMER EXPERIMENT 28 THE LIGHTHOUSE Connect the circuit Notice that the transformer is being used as two coils inductors here Also notice that two transformer taps are not connected although their wires cross in the schematic Press the switch and hold it down for a while The LED blinks every few seconds like a tiny lighthouse Notice that the LED blinks at a constant rate This circuit is called an oscillator It uses feedback Feedback is when you adjust the input to something based on what its output is doing The collector signal is fed back to the base through a coil part of the transformer and the 100uF capacitor If you disconnect this feedback path then the LED will be on continuously because the feedback is what turns the transistor on and off The rate at which the transistor is turned on and off is called the frequency and is controlled by the resistor capacitor and coil in the circuit You can speed up the frequency the LED blink rate by changing the resistor or capacitor to smaller values Try replacing the 1MQ resistor with the 100kQ resistor and see what happens Feedback is necessary for this circuit to work but in some cases it can be harmful In an auditorium or concert hall you sometimes hear a microphone scream when it is located too close to the speaker In this case the sound from the speaker is feeding back into the microphone 1MQ brown black green gold 43 EXPERIMENT 29 ELECTRONIC SOUND No
27. a 9V battery or power supply Switch one 3 3kQ resistor orange orange red gold one 100kQ resistor brown black yellow gold 2LEDs 4 wires Wiring Checklist indicates same position as last experiment M Insert red battery wire or positive P S into j4 and black battery wire or negative P S ground into 3 Insert switch into f4 and f5 The switch may be a tight fit carefully press it in slowly Insert an LED into 920 and 921 side goes into 021 Vf Insert a short wire between 121 and 21 Insert the 100kQ resistor into j5 and j12 Insert a short wire between h12 and j20 Insert the 3 3kQ resistor into i5 and j10 Insert a short wire between g10 and j23 Insert an LED into 023 and g24 flat side goes into 024 O Insert a short wire between 24 and 24 3 3K NTS RIGHTy gt 9V BATTERY or POWER SUPPLY ROCKS WATER l METER PUMP Both LEDs have flat side on right 15 EXPERIMENT 6 COMBINED CIRCUIT Let s combine everything we ve done so far Remove the resistors used in Experiment 3 the other parts are used here Insert the new parts and wires according to the Wiring Checklist Before pressing the switch take a look at the schematic and think about what will happen as you turn the dial on the variable resistor we ll abbreviate this to VR Now press the switch wi
28. ace just add the new parts and wires shown in the schematic and Wiring Diagram Test the four combinations of X and Y as before to determine the state of LED right ON or OFF filling in the table at right This table shows that if neither X nor Y is HIGH then LED right is ON Hence this configuration is called a NOR gate X and Y might represent your burglar alarm and flood detector so if neither X nor Y is on then your all clear light goes on You may also think of this as adding a NOT gate to an OR gate to produce a NOR gate A NOT gate is just the opposite of its input Input NOT LOW HIGH HIGH LOW Gates such as OR NOR and NOT form some of the basic building blocks for computers The combinations of resistors and transistors shown here to build them are a form of Resistor Transistor Logic which was used extensively in early generations of computers and which led to the development of many of today s logic families These basic gates are so commonly used that they have their own symbols OR Gate L NOR Gate NOT Gate LED CLEFT 64 EXPERIMENT 48 THIS AND THAT Take a look at the schematic Can you guess what kind of digital gate this is We ll use almost the same circuit here as in the last experiment Remove the wire between holes a16 and a17 and the one between holes a19 and 19 Add a wire between holes a16 and a19 Also remove the 100kQ resistor we ll re connect it lat
29. ally Westerns MORSE CODE Period Comma Question 2 5 c lt Connect the circuit it is the same oscillator circuit that you have been using Press the switch in long and short bursts to make a sound pattern representing the dots and dashes shown in the table above You can use Morse Code and this circuit to send secret messages to friends in hearing distance without others knowing what you re saying If the sound bothers others in the room then you may send Morse Code messages using flashes of light instead Use the same circuit as you used in Experiment 14 The Electronic Switch and press the switch in the manner shown here During World War II Navy ships sometimes communicated by flashing Morse Code messages between ships using searchlights they did this because radio transmissions might reveal their presence or position to the enemy TRANSFORMER SPEAKER 2 D 2 8 EXPERIMENT 32 SIREN Connect the circuit and press the switch It makes a siren sound You saw earlier how you could change the frequency pitch of the oscillator by changing the oscillator s resistance Well this is basically the same oscillator circuit you ve been using except that now we are electronically varying the oscillator s resistance The large 1MQ resistor and 10hf capacitor cause the base voltage and hence base current on transistor NPN left to rise s
30. attery voltage and circuit resistance will limit the current gain For example if you replace the 1kQ in this circuit with a then the current gain will only be about The circuit resistances not transistor itself are limiting the current and the transistor is said to be saturated TRANSISTOR M Note position of flat side LED LED Cama DN E EFT RIGHT note how the LED flat positioned NPN 28 EXPERIMENT 16 THE SUBSTITUTE Look again at the water pipe analogy for the transistor the lever pivot What would happen if the base and collector were connected together Once there is enough pressure to overcome the spring in check valve DE 0 7V there would be only slight resistance and no current gain This situation should sound familiar since this is exactly how a diode operates When the base and collector of a transistor are connected together the transistor becomes a diode Connect the circuit and press the switch the LED lights This is the same circuit as Experiment 12 One Way Current This demonstrates how transistors can be substituted for diodes and this will occur in practice sometimes for manufacturing reasons 9V TILL Ia 7 AA ST Trt 229 tal position of flat sides 29 EXPERIMENT 17 STANDARD TRANSISTOR BIASING CIRCUIT Connect the circuit and press the switch while turning the variable re
31. ch is widely used in integrated circuits If the transistor base voltages are equal then the currents through the LEDs and collectors will also be equal If one base voltage is higher than the other then that transistor will have more current flowing through it s collector and associated LED You can now replace the two resistors on the right with a different combination and make a new voltage measurement The table below lists different combinations of your PK 101 resistors that you can measure but you don t have to measure them all In some combinations resistors are placed in series or parallel to create new values Remember to disconnect the battery when you re not using the circuit to avoid draining the battery xo 3 0 im sxo ll io ui 309a 3x0 22 3390 ti ui _ toe aa 22 _ aa oo parallel 330 ioa ev 33010 azv 10 3 io sestooasa oo to paalelasoto ie ke 2 seisikn33 mi io seres Tka 33ka CC 34 Note positions of flat sides 2 L aw W J JY A 10K CRIGHT gt gt 33K 35 EXPERIMENT 23 1 5 VOLT BATTERY TESTER Make sure you have a strong 9V battery for this experiment Connect the circuit and connect the battery last since
32. e Breadboard To insert components into the breadboard keep their pins straight and gently push into the holes If the pins get bent and become difficult to insert they can be straightened with a pliers Always make sure components do not touch each other INSERTING PARTS After using your kit for a while some of the wire ends may break off If so you should remove about 3 8 inch of insulation from the broken end with a wire stripper or scissors Before You Begin The rows of the breadboard are marked with letters some rows are marked and and the columns are marked by numbers this allows each hole to be identified individually We will use this notation to smoothly guide you through the experiments Depending on the size of your breadboard several sets of rows may be marked with the same letter but only a portion of the overall breadboard will be used so this will not be a problem The row and column numbers will be expressed as a row column number For example a connection at row b column 26 will be called hole b26 And aconnection at row column 3 will be called hole 3 Some examples of this are shown below IDENTIFYING HOLE LOCATIONS column 3 row hole h6 hole e15 row b hole 7 column 26 EXPERIMENT 1 The Light Bulb First decide if you will use a 9V battery alkaline is best or the adjustable power supply that is part of the XK 150 XK 550 and XK 700 Trainers If using a bat
33. e left and right pins is always 50kQ and the part acts just like one of the other resistors in your PK 101 WIRING DIAGRAM POWER SUPPLY Variable resistors like this one are used in the light dimmers you LED may have in your house and are also used to control the volume ov 50kQ symbol shows in your radio your TV and many electronic devices RESISTOR VARIABLE tat He RESISTOR Parts Needed a 9V battery or power supply Switch one 1kQ resistor marked brown black red gold 50kQ variable resistor one LED 2 wires Wiring Checklist v indicates same position as last experiment Insert red battery wire or positive power supply into hole j4 and black battery wire or negative power supply ground into hole 3 vf Insert switch into holes 14 and f5 vf Insert the LED into holes 920 and 921 side goes into 021 vf Insert a short wire between holes f21 and 21 Insert the 1kO resistor into holes j5 and j15 METER Insert the 50kQ variable resistor into holes e14 g15 and e16 It may be a tight fit carefully press it in slowly a Insert a short wire between holes c14 and j20 ROCKS Be sure all your wires are securely in place and not loose Also make sure the metal into each hole is not touching any other metal including other parts of the same component T ROCK ARM SCHEMATIC WATER DIAGRAM
34. e previous experiments if you feel you need more practice in wiring the circuits Refer back to page 10 if you need to review the resistor color code Connect the circuit according to the schematic and Wiring Diagram and press the switch several times You can see it takes time to charge and discharge the large capacitor because the LED lights up and goes dim slowly Replace the 3 3kQ resistor with the 1kQ resistor now the charge time is faster but the discharge time is the same Do you know why When the switch is closed the battery charges the capacitor through the 1kQ resistor and when the switch is opened the capacitor discharges through the 10kQ which has remained the same Now replace the 100uF capacitor with the 10uF Both the charge and discharge times are now faster since there is less capacitance to charge up If you like you may experiment with different resistors in place of the 1kQ and 10kQ If you observe the LED carefully you might start to suspect the relationship between the component values and the charging and discharging times the charge discharge times are proportional to both the capacitance and the resistance in the charge discharge path A simple circuit like this is used to slowly light or darken a room such as a movie theater WATER METER ON OFF VALVE T _ l PUMP CAPACITOR 20 EXPERIMENT 9 SMALL DOMINATES LARGE CAPACITORS IN SERIES Take a look at the
35. e switch the LED lights up The diode s turn on voltage of 0 7V is easily exceeded and the diode has little effect on the circuit Now reverse the wires to the diode and try again nothing happens The diode is now reverse biased and blocks current flow through the circuit just like the plate and solid stop block the water flow in the drawing shown above You ve probably noticed a similarity between the schematic symbols for the diode and the LED Re wire the diode back to forward biased or remove it from the circuit and then reverse the wires to the LED Press the switch and LED doesn t light do you know why Starting now the equivalent water diagrams will no longer be presented DIODE position side with black stripe as shown 25 EXPERIMENT 13 ONE WAY LIGHT BULBS Diodes made of Gallium Arsenide need a higher voltage across them to turn on usually about 1 5V This turn on energy is so high that light is generated when current flows through the diode These diodes are the light emitting diodes that you have been using To demonstrate this connect the circuit below note that the two LEDs will be referred to as left and right Touch the loose wire to the battery and watch the left LED It will be bright initially as a current flows to charge up the 100uF capacitor and then will dim as the capacitor voltage reaches the battery voltage The right LED will not light since it is reverse biased Then touch the loose wire to the negat
36. e wire This is done in a generator The electric power companies have enormous generators driven by steam or water pressure to produce electricity for your home The voltage expressed in volts V and named after Alessandro Volta who invented the battery in 1800 is a measure of how strong the electric charge from your battery or generator is similar to the water pressure Your PK 101 may be used with either a 9V battery or the adjustable power supply that is part of the XK 150 XK 550 and XK 700 Trainers A power supply converts the electricity from your electric company into a simple form that can be used in your PK 101 If using the power supply then adjust it for 9V This manual will usually refer to the battery this is also meant to refer to the 9V power supply if you are using that instead Notice the and signs on the battery These indicate which direction the battery will pump the electricity similarly to how a water pump can only pump water in one direction The OV or side of the battery is often referred to as ground Notice that just to the right of the battery pictured below is a symbol the same symbol you see next to the battery holder Engineers are not very good at drawing pictures of their parts so when engineers draw pictures of their circuits they use symbols like this to represent them It also takes less time to draw and takes up less space on the page Note that wires are represented simpl
37. ected between the same points in the circuit How bright do you think the LED will be Press the switch and see if you are right The LED is bright so most of the current must be flowing through the smaller 3 3kQ resistor This makes perfect sense when we look at the water diagram with most of the water flowing through the pipe with less rocks In general the more water pipes or resistors there are in parallel the lower the total resistance is and the more water or current will flow The relationship is more complicated than for resistors in series and is given here for advanced students R4 X R R Parallel R4 Ro For two 10kQ resistors in parallel the result would be 5kQ The 3 3kO and 100kQ in parallel in our circuit now give the same LED brightness as a single 3 2kQ resistor To demonstrate this remove the 100kQ resistor and replace it with the 10kQ in the same holes press the switch and the LED should be just as bright The total resistance is now only 2 5kO but your eyes probably won t notice much difference in LED brightness Now remove the 10kQ and replace it with the 1kQ press the switch The total resistance is now only 7700 so the LED should now be much brighter Parts Needed a 9V battery or power supply Wiring Checklist v indicates same position as last Switch experiment one 1kQ resistor brown black red gold vf Insert red battery wire or positive power supply P S into j4 and black batter
38. ectrons The electrons move from atom to atom when an electrical charge is applied across the material Electronics will be easier to understand if you think of the flow of electricity through circuits as water flowing through pipes this will be referred to as the water pipe analogy Wires Wires can be thought of as large smooth pipes that allow water to pass through easily Wires are made of metals usually copper that offer very low resistance to the flow of electricity When wires from different parts of a circuit connect accidentally we have a short circuit or simply a short You probably know from the movies that this usually means trouble You must always make sure that the metal from different wires never touches except at springs where the wires are connecting to each other The electric current expressed in amperes A named after Andre Ampere who studied the relationship between electricity and magnetism or milliamps mA 1 1000 of an ampere is a measure of how fast electrons are flowing in a wire just as a water current describes how fast water is flowing in a pipe Batteries and Generators To make water flow through a pipe we need a pump To make electricity flow through wires we use a battery or a generator to create an electrical charge across the wires A battery does this by using a chemical reaction and has the advantage of being simple small and portable If you move a magnet near a wire then electricity will flow in th
39. ed in music of the sound Record a few comments about the sound you hear e e a a i eo SST 0 047uF You may start to see the same thing we told you about the blinking LED frequency that the frequency increases when you lower the resistance or capacitance It also increases if you lower the inductance but you don t have any other inductors you can substitute Oscillators are among the most important circuits in electronics and most of your remaining experiments will use an oscillator of some form Although the oscillator circuits used here are simple ones some oscillators can be the most difficult circuits to design 44 TRANSFORMER 1M LOOSE WIRE 100K 1 SINGLE 1 1 pores as Sear ssa ts 33K 10K SINGLE LOOSE WIRE 1 005uF pu 9 SPEAKER 3 3K SPEAKER DISC CAPACITORS 473 marking 502 marking LOOSE WIRES 0 047uF 0 005hF 45 EXPERIMENT 30 THE ALARM This circuit is unusual in that you turn it on by disconnecting a wire and turn it off by connecting the wire Connect the circuit including a long wire as the trip wire Notice that there is no sound Now disconnect the trip wire and you hear a sound an alarm This type of circuit is used to detect burglars or other intruders If you use a longer trip wire you can place it across a doorway or window and when someone goes through the doorway or window they will trip on the wire disconnecting it and
40. een achieved as a result The schematic symbol for a transistor is shown below TRANSISTOR Symbol for NPN TRANSISTOR COLLECTOR Flat EMITTER Note the small arrow in the emitter this indicates which direction the current will flow through the device 27 EXPERIMENT 14 THE ELECTRONIC SWITCH Your PK 101 includes three transistors which are all type 2N3904 NPN Bipolar Junction Transistors Connect the circuit according to the schematic and Wiring Diagram Although there is a closed circuit with the battery 1kQ LED and transistor no current will flow since the transistor is acting like an open circuit with no base current the lever arm remains shut Press the switch a base current now flows and opens the lever arm resulting in a large collector current which lights the LED The transistor is being used as an electronic switch Although there is still a normal switch in this circuit there could be many electronic switches controlled by one normal switch TRANSISTOR Note position of flat side flat side is on left EXPERIMENT 15 THE CURRENT AMPLIFIER Connect the circuit and press the switch The right LED in the collector path is brighter than the left LED in the base path because the base current is amplified by the transistor The current gain of a transistor varies anywhere from 10 to 1 000 depending on the type of transistor the ones in your PK 101 have a gain of about 200 Note that the b
41. eft transistor holes 15 015 h15 115 or j15 as shown in the schematic the LED is just as bright So we made a change and nothing happened does this seem like a dull experiment It may seem dull but the important idea here is that we made a big change to the circuit but nothing happened to the LED Take a look at the schematic The circuit to the left of the loose wire reduces the voltage to 4 7V You connect the loose wire to either the 9V battery voltage or the modified 4 7V The circuit to the right of the loose wire creates a fixed current to the LED which will not change even if the voltage 9V or 4 7V to the circuit changes So when you changed which voltage the loose wire was connected to you didn t see any change in LED brightness In case you re not convinced by this let s change the circuit to prove it Place a second LED in series with the 3 3kQ resistor reconnect the 3 3kQ so that it is between d20 and f20 add an LED into holes e20 and f21 with the LED s flat side in 21 Now connect the loose wire to the two voltages as before and you should see the new LED change between bright and dark while the old one remains bright as before You could use a circuit like this when you don t want your performance to be affected as your voltage drops perhaps due to a battery weakening over a long period of use So you could say your circuit is immune to protected against a weak battery LOOSE WIRE LOOSE WIRE NPN CEN
42. ematic This circuit configuration is a type of oscillator called an astable multivibrator What do you think it will do Connect the circuit noting that the transistor bases are not connected although their wires cross in the schematic Initially set the variable resistor VR to its minimum value turn it to the left Press the switch and hold it down One LED is on while the other is off and they change about every second What do you think will happen as you turn the knob on the VR The right LED stays on longer than the left one In this circuit one transistor is always on while the other is off In this type of oscillator there is no inductor the frequency is controlled only by the resistors and capacitors The 100kQ and 10uF determine how long the left transistor is on and the 3 3kO VR and 100uF determine how long the right transistor is on If you want to experiment with changing part values go ahead But don t replace the capacitors with the smaller disc ones you ll see why in the next experiment Blinking lights like this are often used to attract people s attention LED LED CLEFT RIGHT gt NPN NPN lt LEFT RIGHT Note that battery connection point has changed 49V Note positions of LED and transistor flat sides EXPERIMENT 41 NOISY BLINKER This circuit is similar to the last one Connect the circuit noting that the transistor bases are not connected although their wires cross in the schematic Pres
43. enrys H named after Joseph Henry who developed electromagnetic induction at the same time as Faraday or more commonly in millihenrys mH thousandths of a henry or microhenrys uH millionths of a henry A typical inductor and its symbol are shown below Symbol for INDUCTOR INDUCTOR YA Inductors and Transformers Our water pipe analogy we have been using all this time is not entirely accurate Electric current is not the same as water It is a flow of sub atomic particles called electrons that not only have electric properties but also magnetic properties in the water pipe analogy you would have to think of the water as containing millions of very small magnets Inductance expresses the magnetic effects between electrons flowing in the wire of a coil The number of turns windings diameter and length of the coil affect the inductance the thickness of the wire does not The material inside the coil also affects the inductance if you wrap the coil wire around an iron bar which has strong magnetic properties then the magnetic effects are increased and the inductance is increased This does not apply to capacitors which store electric charge in an electric field not a magnetic field 40 If you wrap two wires from different circuits around different ends of an iron bar then a current flowing through the wire from the first circuit will magnetically create a current in the wire from the second circuit If the second coil has twice as ma
44. er Test the four combinations of X and Y to determine the truth table LED lett From it you can see that if X andY are HIGH then LED left will be ON Hence this configuration is called an AND gate X and Y might represent two switches to turn on the same light in your house the room switch and the master switch in the electrical box As with the gates we showed you earlier you could have more than two inputs by just adding more parts to the circuit Now place the 100kQ back into the circuit between holes b24 and b27 as before and look at LED right Since you are just adding a NOT gate as you did in the last experiment you probably know what the new truth table will look like LED right It is NAND gate a combination of AND and NOT X and Y might represent different trip wires for your burglar alarm if either is tripped then that input goes LOW and the alarm sounds AND and NAND have the schematic symbols shown below AND Gate NAND Gate Combinations of AND and OR gates are used to add and multiply numbers together in computers The additional use of NOT NOR and NAND gates allows a computer to represent any input output pattern you can think of By combining these gates with the memory and timing control that flip flops provide today s computers are created 3 3K 1K LED LED SLEF T5 RIGHT Cj NPN CENTER RIGHT EXPERIMENT 49 AUDIO AND NAND Using the LEDs for these trut
45. es a good water detector You could use it as a warning alarm in case your house starts to flood during a storm Or you could use the frequency of the sound as a water saltiness indicator You can also make a water kazoo Pour a small amount of water on a table or the floor and spread it with your finger into a long line Place one of the wires at one end and slide the other along the water You should get an effect just like the kazoo you drew with the pencil though the frequency will probably be different You ve seen how adding salt to water decreases its resistance So would it surprise you to know that pure water distilled water has very high resistance The drinking water you are using here has small amounts of minerals in it which decrease its resistance just like salt does Your body conducts electricity because your body is mostly water with many things mixed in When salt dissolves in water it breaks up into particles called ions which are electrically charged The ions make it easier for electrons to travel through the water similar to how adding impurities makes it easier for electrons to flow through semiconductors Their overall effect is that the resistance of the water is reduced If you have some distilled water in your house try using it with this test SALT lt being added TRANSFORMER SPEAKER ee MIRES LONG WIRES TO WATER 56 EXPERIMENT 40 BLINKING LIGHTS Take a look at the sch
46. ge gold IV Insert an LED into 020 and g21 flat side goes into 021 50kO variable resistor V Insert a short wire between 121 and 21 2LEDs Vf Insert an LED into 023 and 024 flat side goes into 024 3 wires Vf Insert a short wire between f24 and 24 Insert the 50kQ variable resistor into holes e14 g15 and e16 It may be a tight fit carefully press it in slowly Insert the 3 3kQ resistor into ib and i15 Insert the 10kO resistor into j15 and j23 O Insert a short wire between c14 and j20 10K LED RIGHT ON OFF VALVE 50KQ VARIABLE PUMP RESISTOR 16 EXPERIMENT 7 WATER DETECTOR You ve seen how electricity flows through copper wires easily and how carbon resists the flow How well does water pass electricity Lets find out Connect the parts and wires according to the Wiring Checklist and take a look at the schematic There isn t a switch this time so just disconnect one of the wires if you want to turn the circuit off Notice that the Wiring Checklist leaves 2 wires unconnected The LED will be off initially if you touch the two loose wires together then it will be on Now take a small cup make sure it isn t made of metal fill it half way with water and place the two unconnected wires into the water without touching each other The LED should now be dimly lit but the brightness could vary depending on your local water qualit
47. gh the 470 resistor and into the transistor base will increase The current through the LED will then rise rapidly due to the transistor s current gain When the switch is released the capacitor will discharge through the 470Q resistor and the transistor base the LED will dim as this discharge current decreases When the capacitor voltage drops below 0 7V the transistor will turn off If you get impatient you may touch a wire between the two capacitor springs to discharge it instantly Do you know how to change the capacitor charge and discharge times The 100k resistor controls the charge time the 4700 controls the discharge and the capacitor controls both the charge and discharge Replace these parts with some different values and observe the effects Compare this circuit to the one you used in Experiment 8 when we first introduced the capacitor By adding a transistor you can use a large resistor for a slow charge time and still have a bright LED LED 31 EXPERIMENT 19 THE DARLINGTON This circuit is very similar to the last one Connect the components and press the switch hold it down for several seconds The LED will slowly light up Release the switch and the LED stays lit Take a look at the schematic All the current flowing through the emitter of the left transistor will flow to the base of the right transistor So the current flowing into the base of the left transistor will be amplified twice once by each transistor Thi
48. h tables probably seems a little boring So let s use an audio circuit to make a sound instead of turning on the LED Connect the wires according to the schematic and Wiring Diagram Can you tell which digital gate this circuit represents Construct the truth table to find out It is the NAND gate If you use longer wires for X and Y and leave them connected HIGH then you have an alarm with two separate trip wires You can easily modify the circuit to be an AND gate Remove the 3 3kQ resistor the 10uF capacitor and wires e17 to f17 g17 to c38 and a42 to 42 Add wires a42 to e17 and c38 to 30 This audio circuit can also be used with the OR and NOR gates simply by rewiring NPN left NPN center and the 10kQ 33kQ resistors 10UF NPN TRANSFORMER CENTER NPN 047UF SPEAKER LEFT NPN RIGHT 66 EXPERIMENT 50 LOGIC COMBINATION This last circuit is a combination of some of the other digital gates and has 3 inputs See if you can fill in the truth table by just looking at the schematic Then connect the circuit test all eight input combinations and see if you were right LED LED X Y Predicted Measured LOW LOW LOW What could this circuit be used for It might be used to provide power for your telephones Z would be controlled by the phone company and would be high if you paid your phone bill X and Y could be different phones in your house and would be high
49. he larger resistor total resistance is 4 3kQ Also in Experiment 2 you saw how the 1kQ resistor would dominate the circuit when the variable resistor was set for 0 and how the variable resistor would dominate when set for 50kQ Parts Needed WIRING DIAGRAM a 9V battery or power supply POWER SUPPLY cinis s eae s flat w one 1kQ resistor brown black red gold RESISTORS side is on right one 3 3kQ resistor orange orange red gold one 10kQ resistor brown black orange gold one 100kQ resistor brown black yellow gold one LED 1 wire Wiring Checklist indicates same position as last experiment IV Insert red battery wire or positive power supply into hole j4 and black battery wire or negative power supply ground into hole 3 Insert switch into holes f4 and f5 MInsert the LED into holes 920 and 921 side goes into g21 Vf Insert a short wire between holes f21 and 21 O Insert the 3 3kO resistor into holes ib and i12 Insert the 100kQ resistor into holes j12 and j20 avoid touching other components WATER DIAGRAM WATER METER SCHEMATIC PUMP 13 EXPERIMENT 4 PARALLEL PIPES Remove the resistors used in Experiment 3 the other parts are used here Insert the new parts according to the Wiring Checklist Take a look at the schematic There is a low 3 3kQ resistor and a high 100kQ resistor in parallel conn
50. he LED into holes 020 and g21 NOTE The flat side of the LED as shown on the picture above and usually the shorter wire goes into g21 O Insert a short wire between holes h9 and j20 Insert a short wire between holes f21 and 21 Be sure all your wires are securely in place and not loose Also make sure the metal into each hole is not touching any other metal including other parts of the same component The Wiring Checklist and Wiring Diagram show you ONEway of connecting the circuit components using your breadboard There are many other ways that are also correct The important thing is that the electrical connections are as shown in the schematic see below Example of Inserting the Resistor Press the switch and the LED lights up and turns off when you release the switch The LED converts electrical energy into light like the light bulbs in your home You can also think of an LED as being like a simple water meter since as the electric current increases in a wire the LED becomes brighter It is shown again here with its symbol WATER METER Symbol for LED b AA Take a look at the water diagram that follows It shows the flow of water from the pump through the faucet the small pipe the water meter the large pipes and back to the pump Now compare it to the electrical diagram next to it called a schematic Schematics are the maps for electronic circuits and are used by al
51. her but none of these rows are electrically connected to each other This makes 6 rows of 100 holes The red holes will usually be used for your battery or power supply connections and the blue holes will usually be used for your ground battery or power supply connections BREADBOARD CONNECTIONS A E A wapPEPEEPECPPEPEEEEPDDDDPDDID Qadadadgadaaaadadadgdagaadadggdadgadaaddggddagdagddggdgddggddaddgadaagdadagdgadg 5S DS D DS 5 S S 5 6 15 fS 9 L9 T9 ST S 5 ST S S15 15 S 1S STSTS EST TS TS TS S TS TS TS TS DSTS TS IS TSTSTSTS SIS TS TS IST S TS o TTS GSGGGGGSSSSoSSSSSSSSS9SS SESSGSSSSSSSSSSSSSSoSSSSS9SSSSSg D D e SSSNSISISISIS leTeleTelelelelelelelelele ASISISISISISISISISISISISIS DIDDII 8161616 D3 13 D3 3 Ds D3 D3 3 D3 pp aN d lelereleleleleleIeleleTelelelTelelalTelo To ISTSTSISISISISISISISISISISISISISIGISICNS SIsISiSisisisistsistsisisisisistsieh d a d dic 2l ela vele vele le did did 31 SGSSSoSSSSSSoSSSa d OGG d ee d d S d J SISS SiS 3 3 o3 S 9 S Ke Ke Xe 19990 eke 61616 SSBISISSBISSISSSSSISISSSISSISSISSRISSI x 5 Inserting Parts into th
52. hip between voltage current and resistance is known as Ohm s Law after George Ohm who discovered it in 1828 Voltage Current Resistance Resistance Just what is Resistance Take your hands and rub them together very fast Your hands should feel warm The friction between your hands converts your effort into heat Resistance is the electrical friction between an electric current and the material it is flowing through it is the loss of energy from electrons as they move between atoms of the material Resistors are made using carbon and can be constructed with different resistive values such as the seven parts included in your PK 101 If a large amount of current is passed through a resistor then it will become warm due to the electrical friction Light bulbs use a small piece of a highly resistive material called tungsten Enough current is passed through this tungsten to heat it until it glows white hot producing light Metal wires have some electrical resistance but it is very low less than 10 per foot and can be ignored in almost all circuits Materials such as metals which have low resistance are called conductors Materials such as paper plastic and air have extremely high values of resistance and are called insulators Resistor Color Code You are probably wondering what the colored bands on the resistors mean They are the method for marking the value of resistance on the part The first ring represents the first digit of the resistors
53. icult to remove and insert Insert the 4700 resistor into j12 and j20 Insert the 1kQ resistor into i4 and i12 one LED 2 long wires a glass of water and salt Insert the 3 3kQ resistor into h20 and 18 Insert the 10kQ resistor into f20 and 21 Insert a long wire into j21 the other end is unconnected for now Insert a long wire into 25 the other end is unconnected for now TO GLASS OF WATER LAAI VAU WATER ULULI METER VALVE No 2 80 8 8 Ex e E Ut E S TTT A ILLIS ILES A t n ATT TTT ite ROCKS ayo TTT TOEL a eee T NC o en ee y IITTEEEEETTTTTTIVZITVTTTITTILIDIT S Siue BRR ee eee DLL LG PERE TTLTT TET Te tT trie NETL ETT VATS E IND Note Switch is not used here but leave 470 in for future experiments 10K INTRODUCTION TO CAPACITORS Capacitors Capacitors are electrical components that can store electrical pressure voltage for periods of time When a capacitor has a difference in voltage electrical pressure across it it is said to be charged A capacitor is charged by having a one way current flow through it for a short period of time It can be discharged by letting a current flow in the opposite direction out of the capacitor In the water pipe analogy you ma
54. ill stay on until you ground its base 3 3K NPN RIGHT LED CLEFT CRIGHT M ILLOLTLDLLI im e o Y ZZ 712442420 er SLIT CS s HHH p ttt OAT f L Ltt CLL LOOSE WIRE EXPERIMENT 45 FINGER TOUCH LAMP WITH MEMORY Instead of using the wire to flip flop the LED you may also use your fingers as you did in Experiment 20 the Two Finger Touch Lamp We ll use almost the same circuit here as in the last experiment Remove the loose wire and replace the right LED with a diode because we don t need two lamps Wet two fingers and hold one on 9V the row of holes while touching the other to one of the transistor bases This is easy if you touch the metal leads of the resistors connected to these points or you may insert wires into the holes and touch the wires But now you must touch the base of the off transistor to make them flip flop not the on base Do you know why Your body has more resistance than the other resistors in the circuit and cannot short circuit the transistor bases to circuit ground like the wire can So instead we connect the off transistor to the battery to turn it on But this uses two fingers and in Experiment 21 we also had a one finger version so can we do that here Change your wiring add wires or move parts so that metal from 9V is close to metal from the transistor bases Wet a large area of one of your fingers and touch it to 9V and a transistor ba
55. in parallel combine or think in terms of the water diagram again Connect the circuit according to the schematic and Wiring Diagram and press the switch several times to see Capacitors in parallel add together just like resistors in series so here 10uF 100uF 110uF total circuit capacitance In the water diagram we are stretching both rubber diaphragms at the same time so it will take longer than to stretch either one by itself If you like you may experiment with different resistor values as you did in experiment 8 Although you do have two disc capacitors and a variable capacitor which will be discussed later there is no point in experimenting with them now their capacitance values are so small that they would act as an open switch in any of the circuits discussed so far ON OFF VALVE PUMP 22 EXPERIMENT 11 MAKE YOUR OWN BATTERY Connect the circuit according to the schematic and Wiring Diagram Note that one side of the battery and resistor are unconnected and there is a wire connected only to the 100uF capacitor At this time no current will flow because nothing is connected to the battery Now hold the loose wire and touch it to the positive battery wire and then remove it the battery will instantly charge the capacitor since there is no resistance actually there is some internal resistance in the battery and some in the wires but these are very small The capacitor is now charged and
56. ipe would be pushed by the diaphragm and then sucked back by the diaphragm Since the movement of the water current is back and forth alternating it is called an alternating current or AC The capacitor will therefore pass an alternating current with little resistance When the push on the plunger was only toward the diaphragm the water on the other side of the diaphragm moved just enough to charge the pipe a transient or temporary current Just as the pipe blocked a direct push a capacitor blocks a direct current DC Current from a battery is an example of direct current An example of alternating current is the 60 cycle 60 wiggles per second current from the electrical outlets in the walls of your house Construction of Capacitors If the rubber diaphragm is made very soft it will stretch out and hold a lot of water but will break easily large capacitance but low working voltage If the rubber is made very stiff it will not stretch far but will be able to withstand higher pressure low capacitance but high working voltage By making the pipe larger and keeping the rubber stiff we can achieve a device that holds a lot of water and withstands high pressure high capacitance high working voltage large size So the pipe size is determined by its capacity to hold water and the amount of pressure it can handle These three types of water pipes are shown below TYPES OF WATER PIPES LOW CAPACITY BUT HIGH CAPACITY AND LARGE CAPACITY CAN WITH
57. is storing the electricity it received from the battery It will remain charged as long as the loose wire is kept away from any metal Now touch the loose wire to loose side of the 3 3kO resistor and watch the LED It will initially be very bright but diminishes quickly as the capacitor discharges Repeat charging and discharging the capacitor several times You can also discharge the 100uF in small bursts by only briefly touching the 3 3kO If you like you can experiment with using different values in place of the 3 3kQ lower values will make the LED brighter but it will dim faster while with higher resistor values the LED won t be as bright but it will stay on longer You can also put a resistor in series with the battery when you charge the capacitor then it will take time to fully charge the capacitor What do you think would happen if you used a smaller capacitor value When the capacitor is charged up it is storing electricity which could be used elsewhere at a later time it is like a battery However an electrolytic capacitor is not a very efficient battery Storing electric charge between the plates of a capacitor uses much more space than storing the same amount of charge chemically within a battery compare how long the 1004 F lit the LED above with how your 9V battery runs all of your experiments Now is a good time to take notes for yourself on how capacitors work since next we introduce the diode UNCONNECTED LOOSE WIRE UNCONN
58. ive side of the battery ground and watch the right LED It will be bright initially as a current flows to discharge the 100uF capacitor and then will dim as the capacitor voltage drops to zero The left LED will not light since now it is reverse biased As in Experiment 11 you may try different resistor values in this circuit if you like LED LEFT A mM LED RIGHT UNCONNECTED LOOSE WIRE RIGHT LED flat side is on right LEFT LED flat side is on right LOOSE WIRE 26 INTRODUCTION TO TRANSISTORS The Transistor The transistor was first developed in 1949 at Bell Telephone Laboratories the name being derived from transfer resistor It has since transformed the world Did you ever hear of something called a vacuum tube They are large and can be found in old electronic equipment and in museums They are seldom used today and few engineers even study them now They were replaced by transistors which are much smaller and more reliable The transistor is best described as a current amplifier it uses a small amount of current to control a large amount of current There are many different families of transistors but we will only discuss the type included in your PK 101 called the NPN Bipolar Junction Transistor or BUT and made of the semiconductor silicon It has three connection points called the emitter base and collector In our water pipe analogy the BUT may be thought of as the lever
59. l electronic designers and technicians on everything from your PK 101 to the most advanced supercomputers They show the flow of electricity from the battery through the switch the resistor the LED the wires and back to the battery They also use the symbols for the battery Switch resistor and LED that we talked about Notice how small and simple the schematic looks compared to the water diagram that is why we use it DN DFF VALVE SWITCH Now you will see how changing the resistance in the circuit increases the current through it Press the switch again and observe the brightness of the LED Now remove the 10kQ resistor and replace it with a 1kQ resistor marked brown black red gold in that order in the same holes j5 and j9 Press the switch The LED is brighter now do you understand why We are using a lower resistance less rocks so there is more electrical current flowing more water flows so the LED is brighter Now replace the 1kQ resistor with the 100kQ resistor marked brown black red gold in that order and press the switch again The LED will be on but will be very dim this will be easier to see if you wrap your hand near the LED to keep the room lights from shining on it Well done You ve just built YOUR first electronic circuit MORE ABOUT RESISTORS Ohm s Law You just observed that when you have less resistance in the circuit more current flows making the LED brighter The relations
60. lowly As the base current slowly increases NPN left s collector current also increases slowly though it is always much higher than the base current NPN left is now limiting the current just as a resistor does Similar effects occur after you release the switch and the 10uF slowly discharges If you like you can make the sound louder by adding a 1kQ resistor in series with the base middle wire of NPN right TRANSFORMER SPEAKER NPN 70 LEFT NPN RIGHT EXPERIMENT 33 ELECTRONIC RAIN Connect the circuit and press the switch You hear a sound like raindrops The variable resistor VR knob controls the rain turn it to the right to make a drizzle and turn to the left to make the rain come pouring down If you find it inconvenient to turn the VR knob while pressing the switch then just connect a wire across the switch Do you know how this circuit works Remember that as you lower the oscillator s resistance the frequency increases and obviously the VR controls the resistance What would happen if you replaced the 10kQ resistor with the 100kQ Try it The rain is now very slow and it sounds more like a leaky faucet than raindrops You can experiment with changing other component values if you like TRANSFORMER SPEAKER 49 EXPERIMENT 34 THE SPACE GUN Connect the circuit and press the switch several times quickly You hear a sound like a space gun in the movies You can adjust the gun
61. ment 18 Very Slow Light Bulb 31 Experiment 19 The Darlington 32 Experiment 20 The Two Finger Touch Lamp 32 Experiment 21 The One Finger Touch Lamp 33 Experiment 22 The Voltmeter 34 Experiment 23 1 5 Volt Battery Tester 36 Experiment 24 9 Volt Battery Tester 37 Experiment 25 The Battery Immunizer Experiment 26 The Anti Capacitor Introduction to Inductors and Transformers Test Your Knowledge 2 Experiment 27 The Magnetic Bridge Experiment 28 The Lighthouse Experiment 29 Electronic Sound Experiment 30 The Alarm Experiment 31 Morse Code Experiment 32 Siren Experiment 33 Electronic Rain Experiment 34 The Space Gun Experiment 35 Electronic Noisemaker Experiment 36 Drawing Resistors Experiment 37 Electronic Kazoo Experiment 38 Electronic Keyboard Experiment 39 Fun with Water Experiment 40 Blinking Lights Experiment 41 Noisy Blinker Experiment 42 One Shot Experiment 43 Alarm With Shut Off Timer Experiment 44 The Flip Flop Experiment 45 Finger Touch Lamp With Memory Experiment 46 This OR That Experiment 47 Neither This NOR That Experiment 48 This AND That Experiment 49 Audio NAND AND Experiment 50 Logic Combination Test Your Knowledge 3 Troubleshooting Guide For Further Reading Definition of Terms THE EXPERIMENTS IN THIS BOOKLET REQUIRE A BREADBOARD OR CAN BE DONE ONTHE ELENCO XK 150 XK 550 OR XK 700 TRAINERS PARTS LIST Quantity Part Number Descrip
62. n heated to above 360 degrees In addition to having low resistance like other metals solder also provides a strong mounting that can withstand shocks A device which converts electrical energy into sound Switch A device to connect closed or on or disconnect open or off wires in an electric circuit Transformer A device which uses two coils to change the AC voltage and current increasing one while decreasing the other Transient Temporary Used to describe DC changes to circuits Transistor An electronic device that uses a small amount of current to control a large amount of cur rent Transmitter The device which is sending a message usually with radio Truth A table which lists all the possible combinations of inputs and outputs for a digital circuit Tungsten A highly resistive material used in light bulbs Variable Resistor A resistor with an additional arm contact that can move along the resistive material and tap off the desired resistance Voltage A measure of how strong an electric charge across a material is Voltage Divider A resistor configuration to create a lower voltage Volts V The unit of measure for voltage 71
63. ny turns more magnetic linkage as the first coil then the second coil will have twice the voltage but half the current as the first coil A device like this is called a transformer Your PK 101 includes one It consists of a 400mH coil called the primary and a 2mH coil called the secondary wrapped around an iron bar Both coils have middle tap points allowing use of half the coil s inductance In Experiment 26 we used the 400mH coil by itself but usually it will be used to drive a speaker which needs a high current with low voltage The symbol for a transformer is shown on the right TRANSFORMER Symbol for TRANSFORMER The magnetic field created in an iron bar by an electric current in the coil around it can be harnessed if the bar is allowed to rotate itis a motor It could be used to drive the wheels of a car for example The reverse is also true if a magnet within a coil is rotating then an electric current is created in the coil a generator These two statements may not seem important to you at first but they are actually the foundation of our present society Nearly all of the electricity used in our world is produced at enormous generators driven by steam or water pressure Wires are used to efficiently transport this energy to homes and businesses where it is used Motors convert the electricity back into mechanical form to drive machinery and appliances It must be remembered that all of the inductance properties discussed here for
64. ose wire and touch it to the base of the transistor that is on holes b15 and a27 will do or you can touch the resistor leads connected to these points That transistor turns off and the other turns on Do this a few more times until you see that touching the on transistor base flips the transistors and the LEDs You might say that the transistor turning on flips and the one turning off flops Notice that touching the off transistor base has no effect This circuit is called formally known as the bistable switch but is nicknamed the flip flop due to the way it operates The name flip flop may seem silly to you at first but variations of this circuit form one of the basic building blocks for digital computers This circuit can be thought of as a memory because it only changes states when you tell it to it remembers what you told it to do even though you removed the loose wire By combining several of these circuits you can remember a letter or number By combining thousands of these circuits a computer can remember a small book A typical computer has many thousands of flip flops all in integrated circuit form The operation of this circuit is simple If NPN left is on then it will have a low collector voltage Since this collector voltage also connects to NPN right s base NPN right will be off But if you ground NPN left s base then it will turn off and its collector voltage rises turning on NPN right NPN right w
65. r and left LED will be shut off But if the 1 5V battery is weak then the base voltages will be nearly equal and NPN center and LED left will also be on Diodes are often used to make voltage references like this in electronic circuits Remember to disconnect the battery when you re not using the circuit to avoid draining the battery p to side of battery SER al DS LIT IT EEHEHE 11 ssi LET T to side of battery left unconnected for future experiments LED RIGHT LED LEF T5 gt NPN NPN CRIGHT gt CENTER 36 EXPERIMENT 24 9 VOLT BATTERY TESTER Make sure you have a strong 9V battery for this experiment Connect the circuit and connect the wire to the battery last since this will turn on the circuit And be sure to disconnect this battery wire when you re not using the circuit to avoid draining the battery This time you will measure 9V batteries just like the one you may be using to power your PK 101 Take the battery you want to test and hold it between the loose wires the resistor and ground be sure to connect to the and battery terminals as shown If LED right is bright and LED left is off then your battery is good otherwise your battery is weak and should be replaced soon Don t throw any weak batteries away without making sure some measure good with this test because all batteries could fail if your circ
66. ressed in ohms named after George Ohm kilohms 1 000 ohms or megohms MQ 1 000 000 ohms is a measure of how much a resistor resists the flow of electricity To increase the water flow through a pipe you can increase the water pressure or use less rocks To increase the electric current in a circuit you can increase the voltage or use a lower value resistor this will be demonstrated in a moment The symbol for the resistor is shown on the right ROCKS IN THE PIPE RESISTOR Symbol for RESISTOR BE az LEADS for connecting Your Breadboard Breadboards are used for mounting electronic components and to make connecting them together easy and are similar to the printed circuits boards used in most electronic devices Breadboards make it easy to add and remove components Your breadboard has 830 holes arranged into rows and columns some models may have more or less holes but will be arranged the same way BEHBEHUHHEUHHHERHEHHEHHHHE BREADBOARD The holes are connected together as follows There are many columns of 5 holes each The 5 holes within each column are electrically connected together but the columns are not electrically connected to each other This makes 126 columns of 5 holes each Note that electrically connected together means that there is a wire within the breadboard connecting the 5 holes All holes in the rows marked with a blue or a red are electrically connected toget
67. s Mylar capacitors may have been substituted for the disc ones their construction and performance is similar Electrolytic capacitors usually referred to as lytics are high capacitance and are used mostly in power supply or low frequency circuits Their capacitance and voltage are usually clearly marked on them Note that these parts have and polarity orientation markings the lead marked should always be connected to a higher voltage than the lead all of your Wiring Diagrams account for this Disc capacitors are low capacitance and are used mostly in radio or high frequency applications They don t have polarity markings they can be hooked up either way and their voltage is marked with a letter code most are 50V Their value is usually marked in pF with a 3 digit code similar to the stripes used on resistors The first 2 digits are the first 2 digits of the capacitor s value and the third digit tells the power of 10 to multiply by or the number of zeros to add For example the 0 005uF 5 000pF and 047uF 47 000pF disc capacitors in your PK 101 are marked 502 and 473 Capacitors have symbols as follows ELECTROLYTIC CAPACITOR Symbol for SOFT DIAPHRAGM ELECTROLYTIC CAPACITOR FG DISC CAPACITOR Symbol for STIFF DIAPHRAGM DISC CAPACITOR 19 EXPERIMENT 8 SLOW LIGHT BULB Starting with this experiment we will no longer show you the Parts List or the Wiring Checklist Refer back to th
68. s configuration is called the Darlington configuration It has very high current gain and very high input resistance at the base Since there are now two transistors to turn on the capacitor voltage must exceed 1 4V before the LED will start to light And since the input current to the base is so small it will take much longer to discharge the capacitor But the circuit is functionally the same as Experiment 18 and the LED will eventually go dark though it may take a few minutes You can experiment with changing some of the component values if you like Note positions of flat sides EXPERIMENT 20 THE TWO FINGER TOUCH LAMP Take a look at the schematic Youre probably wondering how it can work since nothing is connected to the transistor base It can t but there is another component that isn t shown in the schematic That component is you Connect the circuit according to the schematic and Wiring Diagram including the two loose wires Now touch the loose battery wire with one finger and the loose transistor wire with another The LED may be dimly lit The problem is your fingers aren t making good enough electrical contact with the springs Wet your fingers with water or saliva and touch the springs again The LED should be very bright now You saw in Experiment 7 how water can conduct electricity and since your body is mostly water it shouldn t surprise you that your body can also conduct Your body s resistance varies a lot
69. s the switch and hold it down The LED lights and you hear sound from the speaker Turn the knob on the variable resistor and the frequency of the sound changes Can you tell what the LED is really doing It is actually blinking about 500 times a second but to your eyes it appears as a blur or just dim This is why we told you not to replace the large capacitors with small ones like these in the last experiment You can experiment with changing component values if you like The 470Q resistor limits the sound loudness replace it with a wire to make the sound louder and replace it with a 10kQ to make the sound softer Swapping the two capacitors in the circuit will make the sound frequency higher replacing them with the 10uF or 100uF will make the frequency much lower You can also change some of the other resistors TRANSFORMER SPEAKER NPN NPN LEFT RIGHT 58 EXPERIMENT 42 ONE SHOT Do you know what this circuit will do Connect everything then press the switch and release it The LED is on for a few seconds and then goes out What effect do you think changing the value of the variable resistor will have Try it The higher the resistance the longer the LED stays on This circuit is a variation of the astable multivibrator and is called a one shot multivibrator because the LED comes on once each time the switch is pressed The 33kQ variable resistor and 100uF control how long the LED is on This circuit can
70. s while secondary side has only 2 wires The primary goes in holes e26 e28 and e30 while the secondary goes into f26 and f30 39 The Inductor The inductor can best be described as electrical momentum momentum is the power a moving object has In our water pipe analogy the inductor can be thought of as a very long hose wrapped around itself many times as shown here LARGE HOSE FILLED WITH WATER J WATER PIPE PLUNGER Since the hose is long it contains many gallons of water When pressure is applied to one end of the hose with a plunger the water would not start to move instantly it would take time to get the water moving After a while the water would start to move and pick up speed This is also similar to a long freight train which takes more than a mile to get to full speed or to stop The speed would increase until limited by the friction resistance of the hose as normal If you try to instantly stop the water from moving by holding the plunger the momentum of the water would create a large negative pressure suction that would pull the plunger from your hands Inductors are made by coiling a wire hence they are also called coils From the above analogy it should be apparent that a coiled hose will pass DC a constant or unchanging current with only the resistance of the hose which in electronics will be very low since the hose is a wire If the pressure on the plunger is alternated pushed then pulled fast enough
71. schematic it is almost the same circuit as the last experiment except that now there are two capacitors in series What do you think will happen Connect the circuit according to the schematic and Wiring Diagram and press the switch several times to see if you are right Looking at the water diagram and the name of this experiment should have made it clear the smaller 10uF will dominate control the response since it will take less time to charge up As with resistors you could change the order of the two capacitors and would still get the same results try this if you like Notice that while resistors in series add together to make a larger circuit resistance capacitors in series combine to make a smaller circuit capacitance Actually capacitors in series combine the same way resistors in parallel combine using the same mathematical relationship given in Experiment 4 For this experiment 10uF 100uF in series perform the same as a single 9 1uF In terms of our water pipe analogy you could think of capacitors in series as adding together the stiffness of their rubber diaphragms WATER METER ON OFF VALVE ROCKS ROCKS II Im LJ RUBBER DIAPHRAGMS l PUMP CAPACITOR 21 EXPERIMENT 10 LARGE DOMINATES SMALL CAPACITORS IN PARALLEL Now you have capacitors in parallel and you can probably predict what will happen If not just think about the last experiment and about how resistors
72. se at the same time Now we have a one finger touch lamp with memory 3 3K NPN RIGHT LOOSE WIRE 62 EXPERIMENT 46 THIS OR THAT Now that you re familiar with the flip flop let s introduce some more digital circuits Digital circuits are circuits that have only two states such as high voltage low voltage on off yes no and true false Connect the circuit Take a look at the schematic it is very simple Wires X and Y are considered to be digital inputs so connect them to either the row of holes 9V or HIGH or leave them unconnected this is the same as connecting them to OV or LOW Test the four combinations of X and Y to determine the state of the LED ON or OFF filling in the table below LOW UNCONNECTED LOW UNCONNECTED LOW UNCONNECTED HIGH 9V HIGH 9V LOW UNCONNECTED HIGH 9V HIGH 9V This type of table is called a truth table From it you can see that if X orY is HIGH then the LED will be ON Hence this configuration is called an OR gate X and Y might represent two switches to turn on a light in your house Or they might represent sensors at a railroad crossing if either senses a train coming they start the ding ding sound and lower the gate You could also have more than two inputs by adding more parts to your circuit and more columns to the truth table 63 EXPERIMENT 47 NEITHER THIS NOR THAT Now let s add on to the previous circuit Everything from Experiment 46 remains in pl
73. sistor from right to left from 00 to 50kQ The 100kQ and variable 50kQ are a voltage divider that sets the voltage at the transistor base If this voltage is less than 0 7V then the transistor will be off and no current will flow through the LED As the base voltage increases above 0 7V a small base current starts to flow which is amplified to produce a larger collector current that lights the LED As the base voltage continues to increase the transistor becomes saturated and the LED brightness will not increase further This circuit will normally be used with the voltage divider set so that the transistor is turned on but is not saturated Although this circuit does not have many applications by itself when a small alternating current AC signal is applied to the base then a larger copy of the signal will appear at the collector a small signal amplifier S7 cm Cee 4 TA cco HT oS COA a VARIABLE RESISTOR 30 EXPERIMENT 18 VERY SLOW LIGHT BULB Connect the circuit and press the switch hold it down for several seconds The LED will slowly light up Release the switch and the LED will slowly go dark When you first press the switch all of the current flowing through the 100k resistor goes to charge up the capacitor the transistor and LED will be off When the capacitor voltage rises to 0 7V the transistor will first turn on and the LED will turn on As the capacitor voltage continues to rise the current flow throu
74. t other types will also work SHARPEN IT again and fill in the shape you see below For best results SHARPEN IT again place a hard flat surface between this page and the rest of this booklet while you are drawing Press hard but don t rip the paper Fill in each several times to be sure you have a thick even layer of pencil lead and try to avoid going out of the boundaries Where the shape is just a line draw a thick line and go over it several times The black ink in this manual is an insulator just like paper so you have to write over it with your pencil Shape to be drawn Use a SHARP No 2 pencil draw on a hard surface press hard and fill in several times for best results Take one loose wire and touch it to the left circle Take the other loose wire and touch it to each of the other circles The various circles produce different pitches in the sound like notes Since the circles are like keys on a piano you now have an electronic keyboard See what kind of music you can play with it Note you may get better electrical contact between the wires and the drawings if you wet the wires with a few drops of water or saliva Now take one loose wire and touch it to the right circle 11 Take the other wire and touch it to the circles next to the numbers shown below in order 5 7 7 7 5 1 5 5 7 7 5 1 5 7 7 7 7 5 5 7 5 1 Do you recognize this nursery rhyme It is Mary Had a Little Lamb By now you see
75. tage when the current varies due to magnetic effects Inductor A component that opposes changes in electrical current Insulator A material that has high electrical resistance Integrated Circuit A type of circuit in which transistors diodes resistors and capacitors are all constructed on a semiconductor base Kilo K A prefix used in the metric system It means a thousand of something LED es Common abbreviation for light emitting diode The wires sticking out of an electronic component used to connect it to the circuit Light Emitting Diode A diode made from gallium arsenide that has a turn on energy so high that light is generated when current flows through it Magnetic Field The region of magnetic attraction or repulsion around a magnet or an AC current This is usually associated with an inductor or transformer force of attraction between certain metals Electric currents also have magnetic properties Meg A prefix used in the metric system It means a million of something Micro A prefix used in the metric system It means a millionth 0 000 001 of something Milli m A prefix used in the metric system It means a thousandth 0 001 of something Momentum
76. tery then snap it into its clip Always remove the battery from its clip if you won t be using your PK 101 for a while Insert the red wire from the battery clip into hole j4 and the black wire into hole 3 If using the adjustable power supply then turn it on and adjust it for 9V Connect a wire from the positive adjustable voltage output to hole j4 and another wire from the power supply negative output ground to hole 3 Let s introduce another component the LED light emitting diode It is shown below with its symbol We ll explain what it does in just a few moments Symbol for LED Now insert the components for this circuit into your breadboard according to the list below the first item is for the battery power supply which you already did above which we ll call the Wiring Checklist When you re finished your wiring should look like the diagram shown at right Parts Needed WIRING DIAGRAM a 9V battery or power supply one Switch one 10 resistor marked brown black orange gold in that order one LED 2 wires POWER SUPPLY LED RESISTOR symbol shows flat side is on right Wiring Checklist vf Insert red battery wire or positive power supply into hole j4 and black battery wire or negative power supply ground into hole 3 LI LU 4 Insert switch into holes 14 5 Insert the 10kO resistor into holes j5 and j9 O Insert t
77. th one hand and turn the dial with the other to see if you were right As you turn the VR dial from left to right the left LED will go from bright to very dim and the right LED will go from very dim to visible What s happening is this With the dial turned all the way to the left the VR is 00 much smaller than the 10kQ so nearly all of the current passing through the 3 3kQ will take the VR LED left path and very little will take the 10kQ LED right path When the VR dial is turned 1 5 to the right the VR is 10kQ same as the other path and the current flowing through the 3 3kQ will divide equally between the two LED paths making them equally bright As the VR dial is turned all the way to the right the VR becomes a 50k much larger than the 10k and LED left will become dim while LED right gets brighter Now is a good time to take notes on how resistors work in series and in parallel All electronic circuits are much larger combinations of series and parallel circuits such as these It s important to understand these ideas because soon we ll apply them to capacitors and inductors Parts Needed Wiring Checklist v indicates same position as last experiment a 9V battery or power supply Vf Insert red battery wire or positive P S into j4 and black battery wire Switch or negative P S ground into 3 one 3 3kQ resistor orange orange red gold f Insert switch into f4 and 15 one 10kQ resistor brown black oran
78. that you can draw any shape you like and make electronic sounds with it Experiment on your own as much as you like The circuit here is nearly the same as for Experiment 29 Electronic Sound so you can use the notes you took there to estimate what the resistance is at various points along your keyboard or any other shapes you make Be sure to wash your hands after this test 55 EXPERIMENT 39 FUN WITH WATER Connect the circuit initially the two loose wires are unconnected so there is no sound Now touch each wire with fingers from different hands you should hear a low frequency sound Wetting your fingers with water or saliva will make better electrical contact You are using your body as an electrical component just as you did in Experiment 20 Two Finger Touch Lamp If you like you may make the sound louder by replacing the wire between a23 and a31 with a 3 3kQ resistor actually this makes the circuit the same as the last experiment though the tone of the sound will be different Now take a small cup make sure it isn t made of metal fill it half way with water and place the two wires into the water but without touching each other The sound will now have a much higher frequency because your drinking water has lower resistance than your body Now with the wires still in the water making noise add some table salt to the water and stir to dissolve the salt You should hear the frequency increase as you do this This circuit mak
79. this will turn on the circuit And be sure to disconnect the battery when you re not using the circuit to avoid draining the battery This circuit is a variation of the differential pair configuration used in Experiment 22 you will use it to test your 1 5V batteries Take any 1 5V battery you have AAA AA A B C or D cells and hold it between the loose wires the base of the right transistor and ground be sure to connect to the and battery terminals as shown If the right LED is bright and the center LED is off then your 1 5V battery is good otherwise your 1 5V battery is weak and should be replaced soon Don t throw any weak batteries away without making sure some measure good with this test because all batteries could fail if your circuit is wired incorrectly or if your 9V battery is weak This circuit uses two diodes the left transistor is being used as a diode to create a voltage reference The turn on voltage drops for the diodes are combined to produce a constant voltage of about 1 1V at the base of transistor the center transistor We said earlier that a diode turn on voltage is 0 7V but it varies slightly depending on the current In this application the drops will be about 0 55V for each This is compared to the 1 5V battery voltage at the base of the right transistor in the same manner as Experiment 21 A strong 1 5V battery will easily exceed 1 1V and only the right transistor and LED will be on while the center transisto
80. tion 1 134700 4700 Resistor 0 25W 1 141000 1kQ Resistor 0 25W 1 143300 3 3kQ Resistor 0 25W 1 151000 10kQ Resistor 0 25W 1 153300 33kQ Resistor 0 25W 01 161000 100kQ Resistor 0 25W D 1 171000 1MQ Resistor 0 25W 1 191549 50k Variable Resistor lay down with dial 1 235018 0 005uF Disc Capacitor 1 244780 0 047uF Disc Capacitor 1 271045 10uF Electrolytic Capacitor 1 281044 100uF Electrolytic Capacitor 1 314148 Diode 1N4148 3 323904 Transistor NPN 2N3904 2 350002 Light Emitting Diodes LEDs 1 442100 Transformer 1 540100 Switch push button 1 590098 9V Battery Clip 1 590102 Speaker 8 ohm 0 25 Watt with wires added 1 Wires Bag QUIZ ANSWERS First Quiz 1 electrons 2 short 3 battery 4 increase 5 insulators conductors 6 decreases increases 7 decreases 8 voltage 9 alternating direct 10 increases decreases Second Quiz 1 reverse 2 LEDs 3 amplifier 4 integrated 5 saturated 6 alternating direct 7 decreases increases 8 magnetic 9 increases 10 twice Third Quiz 1 feedback 2 air pressure 3 decreases 4 OR 5 NAND INTRODUCTION TO BASIC COMPONENTS Welcome to the exciting world of Electronics Before starting the first experiment let s learn about some of the basic electronic components Electricity is a flow of sub atomic very very very small particles called el
81. tor configuration in which only one transistor is on at a time AOM naaraat The smallest particle of a chemical element made up of electrons protons etc Electrical energy representing voice or music Base usen The controlling input of an NPN bipolar junction transistor A device which uses a chemical reaction to create an electric charge across a material The state of the DC voltages across a diode or transistor Bipolar Junction Transistor BJT A widely used type of transistor Bistable Switch A type of transistor configuration also known as the flip flop eA abbreviation for Bipolar Junction Transistor Capacitance The ability to store electric charge Capacitor An electrical component that can store electrical pressure voltage for periods of time Carbon A chemical element used to make resistors Clockwise In the direction in which the hands of a clock rotate C01l nm etas When something is wound in a spiral In electronics this describes inductors which are coiled wires Collector The controlled input of an NPN bipolar junction transistor Color Code A method for marking resistors using colored bands Conductor A material that has low electrical resistance
82. uit is wired incorrectly As you d expect this circuit is similar to Experiments 22 and 23 From the schematic you can see that we are using resistors to set the voltages at the bases of the transistors The resistor values were selected so that if the two battery voltages are equal then the right transistor s base will have a higher voltage and only LED right will be lit as in Experiment 23 when we had a good 1 5V battery In fact LED left will only be on if your PK 101 s battery voltage is at least 2V higher than that of the battery you are testing We do this because we don t want to reject a good battery that s just not as good as our reference battery Of course if our reference battery is weak then any battery tested will appear good Remember to disconnect the battery or turn off your power supply when you re not using the circuit to avoid wasting energy gt to side of battery to side of battery 4 1 1 pe al 9 BATTERY eT Now it s time to introduce another component 37 EXPERIMENT 25 BATTERY IMMUNIZER Connect the circuit according to the Wiring Diagram and schematic Note that the collectors of the center and right transistors are not connected although their wires cross over each other in the schematic Connect the loose wire to 18 or any of the holes in the same row which are connected to the battery the LED is bright Now connect the loose wire to the emitter of the l
83. w it s time to make some noise To do this we need a speaker A speaker converts electrical energy into sound It does this by using the energy of an AC electrical signal to create mechanical vibrations These vibrations create variations in air pressure called sound waves which travel across the room You hear sound when your ears feel these air pressure variations You need high current and low voltage to operate a speaker so we will always use the transformer with the speaker Remember that a transformer converts high voltage low current to low voltage high current We create an AC signal for the speaker using the oscillator circuit introduced in the last experiment with minor changes A speaker has a schematic symbol like this SPEAKER Symbol for SPEAKER Connect the circuit notice that two transformer taps are not connected although their wires cross in the schematic Also notice there are 4 resistors and 4 capacitors connected to the 3 3kQ resistor we are using the row of holes at the bottom to make the connections easier and 2 loose wires connected to the transformer We are also using the disc capacitors for the first time refer back to page 19 to review them if you need to Connect the transformer to one resistor and one capacitor at a time then press the switch and listen All the combinations are listed below you don t need to try all of them but try some and see if there is a pattern in the frequency or pitch a term us
84. water by adjusting an opening in the pipe with a faucet Unfortunately you can t adjust the thickness of an already thin wire But you could also control the water flow by forcing the water through an adjustable length of rocks as in the rock arm shown below In electronics we use a variable resistor This is a normal resistor 50 in your PK 101 with an additional arm contact that can move along the resistive material and tap off the desired resistance VARIABLE RESISTOR INSULATING BASE MATERIAL WIPER CONTACT THIN LAYER OF MOVABLE RESISTIVE MATERIAL ARM STATIONARY CONTACT The dial on the variable resistor moves the arm contact and sets the resistance between the left and center pins The remaining resistance of the part is between the center and right pins For example when the dial is turned fully to the left there is minimal resistance between the left and center pins usually 00 and maximum resistance between the center and right pins The resistance between the left and right pins will always be the total resistance 50kQ for your part VARIABLE RESISTOR CENTER PIN Symbol for VARIABLE RESISTOR a LEFT D RIGHT PIN Now let s demonstrate how this works 11 EXPERIMENT 2 THE BRIGHTNESS CONTROL Remove the 10kQ resistor used in Experiment 1 the other parts are used here Insert the new parts according to the Wiring Checklist below Press the switch and the LED lights up it may be dim
85. when you pick up the phone The transistor emitters would then provide voltage to the rest of the telephone circuit Congratulations You ve finished all the experiments and can now show your friends how much you know about electronics You are now ready to move on to the next level of Elenco Electronics Learning Series You can also learn how to solder using Elenco s line of quality soldering kits Check out our website http www elenco com or see the back cover of this booklet for how to contact us to order these products TEST YOUR KNOWLEDGE 3 1 Adjusting the input to something based on what its output is doing is an example of 2 A speaker converts electrical energy into variations called sound waves 3 An oscillators frequency when you add resistance or capacitance 4 A NOR gate followed by a NOT gate is the same as an gate 5 An AND gate followed by a NOT gate is the same as a gate Answers are on page 3 TROUBLESHOOTING GUIDE Check your wiring against the Wiring Diagram and the schematic very carefully Be sure all your wires and components are securely in place in the correct hole and not loose Make sure the metal in the wires and components is not contacting any other metal since this will create short circuits Nearly all problems are due to wiring errors e Remember that the battery and electrolytic capacitors have and terminal markings and be sure to correctly position the transistors
86. xperiment Connect the circuit according to the Wiring Diagram and schematic connect the battery last since this will turn on the circuit And be sure to disconnect the battery or turn off your power supply when you re not using the circuit to avoid draining the battery The part of the circuit to the left of the dashed line in the schematic is the voltmeter the two resistors on the right produce a voltage that you will measure Notice that the variable resistor VR will always act as a 50kO across the battery but by turning its knob you adjust the voltage at the base of the left transistor By turning this knob you can make one LED brighter than the other indicating that the voltages at the bases of the two transistors are not equal Adjust the VR so that the two LEDs are equally bright The transistor base voltages are now equal To determine what voltage you have measured simply subtract the percentage you turned your VR dial from 100 and multiply by 0 09 If you like you can calculate what voltage you should have measured Your measurement may differ from this due to the tolerances in the resistors and the VR dial but you should be close The resistors on the right are a voltage adjuster just like the VR is and the voltage you measured at the base of the right transistor is RLower 33kQ VCalculated X VBattery x 9V 6 9V Rupper Rrower 10kQ 33kQ This circuit is a form of the Differential Pair transistor configuration whi
87. y You are now seeing a demonstration of how water conducts passes electricity A small cup of water like this may be around 100kQ but depends on the local water quality Try adding more water to the cup and see if the LED brightness changes it should get brighter because we are making the water pipe larger Since the LED only lights when it is in water now you could use this circuit as a water detector Now adjust the amount of water so that the LED is dimly lit Now watching the LED brightness add some table salt to the water and stir to dissolve the salt The LED should become brighter because water has a lower electrical resistance when salt is dissolved in it Looking at the water pipe diagram you can think of this as a strong cleaner dissolving paintballs that are mixed in with the rocks You could even use this circuit to detect salt water like in the ocean Wiring Checklist indicates same position as last experiment Parts Needed Wf Insert red battery wire or positive P S into j4 and black battery wire 9V battery or power supply or negative P S ground into 3 one 4702 resistor yellow violet brown gold MW Insert an LED into 020 and g21 side goes into 021 one 1kQ resistor brown black red gold one resistor orange orange red gold Note Keep the switch in the breadboard unconnected until later one 10kQ resistor brown black orange gold experiments as it can be diff
88. y by lines on the page WATER PUMP BATTERY Symbol for BATTERY C 9 Gesn The Switch Since you don t want to waste water when you are not using it you have a faucet or valve to turn the water on and off Similarly you use a switch to turn the electricity on and off in your circuit A switch connects the closed or on position or disconnects the open or off position the wires in your circuit As with the battery the switch is represented by a symbol shown below on the right VALVE SWITCH Symbol for SWITCH e You have been given one of the two above switches The Resistor Why is the water pipe that goes to your kitchen faucet smaller than the one that comes to your house from the water company And why is it much smaller than the main water line that supplies water to your entire town Because you don t need so much water The pipe size limits the water flow to what you actually need Electricity works in a similar manner except that wires have so little resistance that they would have to be very very thin to limit the flow of electricity They would be hard to handle and break easily But the water flow through a large pipe could also be limited by filling a section of the pipe with rocks a thin screen would keep the rocks from falling over which would slow the flow of water but not stop it Resistors are like rocks for electricity they control how much electric current flows The resistance exp
89. y think of the capacitor as a water pipe that has a strong rubber diaphragm sealing off each side of the pipe as shown below PIPE FILLED WITH WATER A Rubber Diaphragm in pipe is like a Capacitor PLUNGER RUBBER DIAPHRAGM SEALING CENTER OF PIPE If the pipe had a plunger on one end or a pump elsewhere in the piping circuit as shown above and the plunger was pushed toward the diaphragm the water in the pipe would force the rubber to stretch out until the force of the rubber pushing back on the water was equal to the force of the plunger You could say the pipe is charged and ready to push the plunger back In fact if the plunger is released it will move back to its original position The pipe will then be discharged or with no pressure on the diaphragm Capacitors act the same as the pipe just described When a voltage electrical pressure is placed on one side with respect to the other electrical charge piles up on one side of the capacitor on the capacitor plates until the voltage pushing back equals the voltage applied The capacitor is then charged to that voltage If the charging voltage was then decreased the capacitor would discharge If both sides of the capacitor were connected together with a wire then the capacitor would rapidly discharge and the voltage across it would become zero no charge What would happen if the plunger in the drawing above was wiggled in and out many times each second The water in the p
90. y wire or negative power supply ground into 3 one 3 3kQ resistor orange orange red gold d spond ts t switch into f4 and f5 one 10kQ resistor brown black orange gold nser i one 100kQ resistor brown black yellow gold ed A gal one LED vf Insert the 3 3kQ resistor into i5 and i12 O Insert the 100kQ resistor into jb and j12 Insert a short wire between h12 and j20 2 wires WIRING DIAGRAM Note From now on there will be less description for frequently used parts WATER METER 9v 9V 4 A San SUUS BATTERY or POWER SUPPLY ROCKS PUMP 14 EXPERIMENT 5 COMPARISON OF PARALLEL CURRENTS Since we have two resistors in parallel and a second LED that is not being used let s modify the last circuit to match the schematic below It s basically the same circuit but instead of just parallel resistors there are parallel resistor LED circuits Remove the resistors used in Experiment 4 the other parts are used here Insert the new parts according to the Wiring Checklist Replace the 100kQ resistor with several values as before such as 1kQ 10kQ and others if you wish pressing the switch and observing the LEDs each time The brightness of the right LED will not change but the brightness of the left LED will depend on the resistor value you placed in series with it Parts Needed

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