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LEARN HOW TO GET THE MOST OUT OF YOUR

1. What We S66 ocd RENE S 6 Experiment 2 Adjustable AC voltage i rne 7 Connection layout ERRR 7 T 7 eap i a RET Oo EODD 7 lioc 7 IOW O 7 Experiment 3 Measuring AC grid frequency and period 9 CONE COU 9 epi QU PUR 9 9 a ro 9 Experiment 4 Rectified AC single phase 11 Connection layout ec M 11 eap ziU E M MM MIO TO E qo D 11 ulcer 11 al PT 11 EE EET 11 Experiment 5 Rectified dual phase comi ts aat nuoc tin pue Sax tac dedeisick coi at x Eu nm ruit unu E 12 Connection NAY AEA
2. AC measure the AC voltage supplied to the board voltage How How 1 Turn on the HPS140 Handheld Pocket Scope see HPS140 manual for How To instructions 1 Turn on the HPS140 Handheld Pocket Scope see HPS140 manual for How To instructions 2 Place the probe switch x1 x10 to x1 2 Place the probe switch x1 x10 to x1 The unit always starts up in auto setup mode You can tell that 11 cose Trimmer RV1 allows us to adjust the output voltage on test point 3 between OV and the full input voltage Turn RV1 fully anti clockwise OV output The trace on our oscilloscope screen remains a flat line as there is no input voltage Fill 0 2064 it is in auto setup mode because the readouts for Volts div and Time div are displayed in reverse video white characters on dark background Thanks to the auto setup mode the unit takes care of V div and time div for you you do not have to do anything In the lower right hand corner the RMS value of the supplied AC voltage is displayed More about auto setup in the next experiment Som cd iu What we see e Select AC coupling see HPS140 manual for How To instructions e Settime div to 5ms div e Set volts div to 10V div Slightly turn RV1 clockwise until a sine wave is displayed the screen You only need to turn it slightly before the signal appears If the signal goes off screen turn RV1 anti clock wise
3. AEEA AEEA EEE AE EEE 12 Connection SUN Mell Vs serari E mn 12 PU OSG EEEE mc 12 FOW E 12 Wise IE 13 mice C M TER 13 Experiment 6 Smoothed versus unsmoothed DC ripple e reeeee nnne nnns 14 CGonnection ioi c 14 Connection SUmMMATY TIT T Umm 14 lisse S 14 PTS MET 14 E R 14 Experiment 7 DC measurement du 16 Connection layout TT R 16 Connection E o o 0 OLD UESTRE 16 grece 16 16 miser c E 17 Experiment 8 Waveform with adjustable frequency 18 Connection layout 18 Connection SUMMA eresie aE EE ERRENA o Om 18 glijsisc E E 18 go o 18 POW OSS c 19 ERE tetas 19 W
4. USB PC FUNCTION GENERATOR The PCGU1000 is a digital function generator which can be connected with a PC via USB Standard signal waves like e g sine triangle and rectangle are available other sine waves can be easily created d 02 1 05 SCOPE GENERATOR wo channel oscilloscope spectrum analyser recorder function generator bode plotter With he generator you can create your own waveforms using the integrated signal wave editor J 2 CH USB PC OSCILLOSCOPE The PCSU1000 digital storage oscilloscope uses the power of your PC to visualize electrical signals Its high sensitive display resolution down to 0 15mV combined with a high bandwidth and a sampling frequency of up to 1GHz are giving this unit all the power you need NCED PERSONAL Feature packed 2 channel 2x30MHz oscilloscope Full auto setup numerous readouts several display modes and serial interface Comes complete with power adaptor battery pack and probes digital oscilloscope 40 5 5 digital function generator 1Mhz simple but easy to use power supply up to 12VDC The 3 units are electrically separated for ease of measurement SK1 Y lt 5 Q e The board generates a number of safe real world signals which we will use to perform measurements Get familiarized with AC DC and frequency measurements sine and Square waves power supply ripple full and half wave rectifiers oscillators etc
5. VELLEMAN Ltd limits its responsibility to the reparation of defects or as VELLEMAN components Ltd deems necessary to the replacement or reparation of defective components Costs and risks connected to the transport removal or placement of the product or any other costs directly or indirectly connected to the repair will not be reimbursed by VELLEMAN components Ltd VELLEMAN compo nents Ltd will not be held responsible for any damages caused by the malfunctioning of a unit GARANTIE Ce produit est garanti contre les d fauts des composantes et de fabrication au moment de l achat et ce pour une p riode de deux ans partir de la date d achat Cette garantie est uniquement valable si le produit est accompagn de la preuve d achat originale Les obligations de VELLEMAN S A se limitent la r paration des d fauts ou sur seule d cision de VELLEMAN S A au remplacement ou la r paration des pi ces d fectueuses Les frais et les risques de transport l enl vement et le renvoi du produit ainsi que tous autres frais li s directement ou indirectement la r paration ne sont pas pris en charge par VELLEMAN S A VELLEMAN S A n est pas responsable des d gats quels qu ils soient provoqu s par le mauvais fonctionnement d un produit WAARBORG Dit produkt is gewaarborgd wat betreft gebreken in materialen en vakmanschap op het ogenblik van de aankoop en dit gedurende een periode van TWEE JAAR vanaf de aankoop De waarborg geldt enkel indien
6. to make a diode bridge Single diode Connection summary le A GND clip 4 Probe tip 5 Purpose The purpose of this experiment is to show what dual phase rectified AC looks like on a scope screen and to show the difference with single phase rectified AC Diode bridge How 1 Turn on the HPS140 Handheld Pocket Scope see HPS140 manual for How To instructions 2 Place the probe switch x1 x10 to x1 elect 5ms div and 4V div Exercise As the switch is still set to single phase rectification the display will show the same trace as In experiment 3 we have learned how to measure the frequency of a repeating waveform Can you measure the period and frequency of both the single phase and dual phase rectified signal Answer 10ms 100Hz or 8 33ms 120Hz with experiment 4 Now check what happens when you flip the switch from single phase to dual phase rectification Flip the switch back and forward to clearly see the difference between both settings 14 A EU 19 Smoothed versus unsmoothed DC ripple 15 Experiment 6 Smoothed versus unsmoothed MENO esc CO a od measurement DC ripple Flip SW1 back to single phase rectification Connection layout NOTES gt AUTO Welt oo Default your scope starts up with DC coupling selected p Change that to AC coupling see manual for how to instructions EE ZI t Now the scope will only show
7. until the signal is correctly displayed In the lower right LEER hand corner you can read the current RMS value of the AC voltage measured e g 100mV 0 1V Note the readout in the bottom right hand corner displays the RMS value of the measured AC voltage Different readouts are available see HPS140 manual for How To instructions Note If you live in an area where the AC grid frequency is 60Hz instead of 50Hz e g US the image may slightly vary 8 Exp 2 Adjustable AC voltage advantages of the auto setup function Measuring AC grid frequency and period Turn RV1 a little further clockwise The signal goes off How can we display the current signal correctly again Increase the V div setting to 0 1V div As you will see the signal fits the screen again EE ELTTI ERT LEI LET EET zT RU Da Ibis THIN If you turn RV1 clockwise again the signal will go off screen again Changing V div to 0 2V div once again restores the display 1 T 3T D BEA You can continue this process until RV1 is turned fully clockwise In that case we will measure the full input voltage which we also measured in experiment 1 Is there a better way of measuring unknown voltages Yes there is by using the auto setup function Keep pressing any of the arrow keys until V div and time div are displayed in reverse video The trace immediately adjusts for optimal viewing Now you can adjust the voltage f
8. LEARN HOW TO GET THE MOST OUT OF YOUR DIGITAL Sasissuistas EDU06 Oscilloscope Tutor Board HEDU06 By Velleman n v Nelleman EL etting started The purpose of this board is to learn how to perform basic measurements with an oscilloscope Most experiments can be performed with any digital storage scope Some experiments can be performed with an analog scope Experiments in this project are performed using the Velleman HPS140 Handheld Pocket Scope All experiments require basic knowledge of terms such as AC and DC voltage cur rent resistance etc Make sure to check You Tube as well it features a short movie for each experiment See the product page on our website for the latest available translated manual Download de laatst beschikbare vertaalde handleiding op de product pagina van onze website Consultez la fiche technique sur notre site web pour la toute derni re version de la traduction du mode d emploi Eine aktuelle Version der deutschen Bedienungsanleitung finden Sie auf der Produktseite unserer Website Para descargarse el manual del usuario en espafiol m s recientes consulte la p gina del producto en nuestra web WARRANTY This product is guaranteed against defects in components and construction from the moment it is purchased and for a period of TWO YEAR starting from the date of sale This guarantee is only valid if the unit is submitted together with the original purchase invoice
9. Learn what terms such as V div Time div trigger level auto setup etc mean All ex periments featured in this project are performed with the Velleman Most experiments be done with any digital storage scope Some experi ments can be performed with analog scope Signals alternating current AC adjustable AC full and half wave rectified AC smoothed direct current DC ripple astable oscillator Velleman NV Legen Heirweg 33 B 9890 Gavere Belgium HEDUO6 1 5410 704 Nelleman ae 329 449
10. OS ANO a partir de la fecha original de compra La garant a s lo tendr validez cuando se presente el producto con la factura de compra original VELLEMAN S A se limitar a reparar defectos pero es libre de reparar o reemplazar partes defectuosas VELLEMAN S A no reembolsar los gastos de transporte o riesgos ni los gastos para trasladar y reinstalar el producto as como todo otro gasto directamente o indirectamente relacio nado con la reparaci n VELLEMAN S A no asumir ninguna responsabilidad por dafios de cualquier naturaleza causados por un producto defectuoso Contents irpo T PR 2 OSes Cope oF L ch RETO E OO Emm 4 Analog vers s digital c 4 NV ANTONIA air E DH 4 Meas ring dd euaaroudididasdmumnbastereanieddeets 5 Connecting the E Pup 5 Setting up the board eieae iA 5 Experiment 1 Measuring AG voltate la RC c cim hdd 6 Connection e TEc KKKA 6 Connection SUMMATY sesser bE DERE ME dod d ACH de en EPA AEREE FEMINIS dd dd DN SC Cad taa CLR DO 6 FUNGI G eaten ane T PM 6 FOW HT na ck be H 6
11. ce the readout might not be correct In most cases this ground level will be the center of the screen however this is not mandatory DC voltage DC Direct Current With DC the current flows in a single direction it does not reverse A DC source has a polarity and Input coupling The drawing shows typical oscilloscope input circuit There are 3 possible settings AC coupling DC coupling and GND With AC coupling a capacitor is put in series with the input signal This capacitor blocks any DC com ponent of the signal and passes only AC With DC coupling the capacitor is bypassed and both the AC and DC compo nent of the signal are passed Low frequency signals 20Hz should always be displayed using DC coupling Should AC coupling be used the internal coupling capacitor will interfere with the signal and the displayed signal will not be correct NI NA NL NA NA DC coupling AC coupling GND coupling Sample rate Usually expressed in samples or megasamples second sometimes in MHz It is the number of times per second the digital oscilloscope looks at the signal at the input The more it looks the better it is able to recre ate a faithful image of the waveform on the screen Theoretically the sample rate needs to be twice the max frequency of the applied signal however for best results a sample rate of 5 times the max frequency is recom mended The HPS140 samplerate is 40Ms s or 40MHz Sensitivity Indica
12. ct DC voltage It is clear that our rectified AC voltage needs smoothing This can be done with an electrolytic capacitor see diagram of this board How 1 Place the probe switch x1 x10 to x1 2 Make sure to flip SW1 to the correct position 3 Turn on the HPS140 Handheld Pocket Scope It will start up in auto setup mode as always Watch the screen closely You will notice that the trace is almost flat so the capacitor is doing a good job at smoothing our rectified AC voltage Yet it still wobbles a bit If you flip the switch from single phase to dual phase rectification the wobbling will be reduced 0 130 Basically the capacitor acts as a temporary storage device It provides power to the rest of the circuit during the interruption of the waveform remember single phase rectification With dual phase rectification this interruption is not present so the capacitor has less work to do The remaining wobble of the waveform is called ripple One of the key features of a good DC supply is low ripple Good to know Use 1000yF per ampere so e g if you design a 2A power supply you need a smoothing capacitor of at least 2000 2200pF is the closest value that is suited for your purpose 16 NND D M 17 Experiment 7 DC measurement Connection layout NOTES Connection summary GND clip 4 Probe tip 6 Purpose The purpose of this experiment i
13. e BEET CES LES CET EZT CET LEI EET ml a 148 ERE UEO 19 Experiment 8 Waveform with adjustable Exercise frequency Press and hold the upper right hand button to enter the menu Release and press again a number of times until Trg Level is Connection layout NOTES highlighted Wait until unit quits the menu I Now look at the bottom left hand side of the screen the trigger symbol is displayed 2277 The arrow buttons allow you to shift the trigger level up or down Check out what happens if you move it al the way down At a certain point the waveform becomes unstable and starts scrolling from right to left If you look closely this happens when the trigger point is shifted below the bottom of the waveform If you shift it up again so that the trigger point is located between the bottom and the top of the wave form it will be stable again It is even possible to use the trigger setting to exactly determine the point where the scope will trigger Try moving the trigger gap up and down between the top and bottom of the waveform The waveform will shift horizontally in such a way that that the beginning of the trace corresponds with the trigger level What is the purpose of the slope symbol Connection summary Let s change the slope and see what happens Press and hold the upper right button to enter the GND clip 4 menu Release the button and press it a number of times until Slope is
14. ern that repeats over time e g the waves of the sea One cycle or period of a wave is the part of the wave that repeats itself When shown on the screen of an oscilloscope it is called a waveform There are many differ ent waveforms A couple of them will be used in our experiments 1 2 3 4 m m Sine waves Atypical example The AC power grid Full wave rectified AC The output of a full wave diode rectifier Half wave rectified AC The output of a half wave diode rectifier DC voltage Yes oscilloscopes can also measure DC Sawtooth waveform In this case ripple Square wave The board features a simple two transistor oscillator which produces a square wave 5 Measuring probe To be able to display waveforms we need to connect the signal to the input of the oscilloscope Similar to a multimeter the oscilloscope uses a measurement lead but here it is called a probe Probe tip The of your probe It is needle shaped to ensure a good electrical contact with your measuring point BNC connector Connects to the input of your oscilloscope e Ground lead with alligator clip The of your probe Connect the alligator clip to the ground or of the circuit you wish to examine Probe clip Clips onto the probe tip and allows you to connect the probe to the measuring point in a permanent way so you have your hands free 9 x1 x10 switch When set to x1
15. hat is the purpose of the slope symbol _ 19 GOSS NY ec X AYY 20 3 22 4 Oscilloscope basics While a multimeter shows an instant voltage level or an average voltage level an oscilloscope is capable of displaying voltage levels over a period of time Voltage is displayed vertically X axis versus time Y axis APNE Time Oscilloscopes can be used to for applications such as e Looking at the shape of a signal e Measuring the amplitude and frequency of a signal e Measuring the time between to events e Looking for anomalies such as clipping noise distortion spikes ripple etc Voltage Analog versus digital There are two basic types of oscilloscopes analog and digital scopes Digital oscilloscope analog oscilloscope Each type has its typical applications advantages and disadvantages The advantage of digital scopes is that they are able to capture and store events for further study They are also more user friendly as they require less setup in order to show a picture of your signal For our experiments we will use a digital scope Waveforms An oscilloscope will mainly display and measure waveforms A wave is a patt
16. he input coupling to GND and wait a couple of seconds until the DC readout in the lower right hand corner displays 0 0mV If the settings have been performed correctly your scope will now show a flat trace above the centre of the screen and the readout in the bottom right hand corner will show the measured DC voltage Don t forget to switch it back to DC coupling again POTTI TITTI ITO EPOD ata ge a SE 8 810 Exercise If you move the probe clip to test point 7 or test point 8 you will notice that the scope will automati cally adapt the V div setting and the measured DC voltage will drop to 2 3 or 1 3 of the original value because of the resistor divider R2 R3 R6 FU 2 3053 t Bans LEES as Testpoint 8 Testpoint 7 To T PD 0 Cal e LY S Loo S 4 e d 1 EL x AK 12 A 8 H M T Probe tip to test point 4 ground clip to test point 6 What happens if you swap the probe tip and ground clip The trace jumps from above the centre of the screen to below centre and the readout shows the same value but negative This is logical as the ground clip is the ground or and the probe clip is the positive of our instrument Test point 4 is at ground level while test point 6 is positive so we get a negative readout et n
17. het produkt voorgelegd wordt samen met het origineel aankoop bewijs De verplichtingen van VELLEMAN N V beperken zich tot het herstellen van defecten of naar vrije keuze van VELLEMAN N V tot het vervangen of herstellen van defecte onderdelen Kosten en risico s van transport het wegnemen en terugplaatsen van het produkt evenals om het even welke andere kosten die rechtstreeks of onrechtstreeks verband houden met de herstelling worden niet door VELLEMAN N V vergoed VELLEMAN N V is niet verantwoordelijk voor schade van gelijk welke aard veroorzaakt door het falen van een product GARANTIE Dieses Produkt tragt eine Garantie f r fehlerhaftes Material oder Verarbeitungsschaden im Moment des Ankaufs Sie ist ZWEI JAHRE g ltig ab Ankaufsdatum Die Garantie kann nur beansprucht werden wenn das Produtk mit der Originalrechnung abgegeben wird Die Verpflichtungen der VELLEMAN AG beschranken sich auf die Aufhebung der Fehler oder nach freier Wahl der VELLEMAN AG auf den Austausch oder die Reparation der fehlerhaften Teile Kosten und Risiken des Transports das Entfernen und Wiedereinsetzen des Produkts sowie alle anderen Kosten die direkt oder indirekt mit der Reparation in Verbindung gebracht werden k nnen werden durch die VELLEMAN AG nicht zur ckerstattet VELLEMAN AG ist nicht f r Schaden gleich welcher Art entstanden aus der fehlerhaften Funktion des Produkt haftbar GARANT A El producto est garantizado durante un per odo limitado de D
18. highlighted Wait for the Probe tip 9 unit to exit he menu Now look at the bottom left hand side of the screen the slope symbol is dis played Press any arrow key to toggle between rising and falling slope Take a look at the waveform and see what happens Purpose The purpose of this experiment is to demonstrate the use of the trigger function How 1 Place the probe switch x1 x10 to x1 2 Flip SW1 into the full wave position 3 Turn on the HPS140 Handheld Pocket Scope it will turn on in auto setup mode Select DC coupling The unit displays a square wave The rising edge of the square wave is not perfectly square due to the limitations of this simple Conclusion Trigger and slope settings allow us to get a stable signal and make it T two transistor circuit Anyway the resulting waveform is fine for Bis ITE easier for us to study parts ofa complex signal our experiment I Nig bad bed beet poo p Wareulcussclcsecicenoelnenelzueuoluaceelesenicceulicnenisucelzues 0 R l eae B 31U rising slope falling slope So the slope setting also determines where the scope will trigger This can be on the rising or on the falling slope of the signal Set unit to 10ms div and 2V div Adjust RV2 in such a way that the waveform looks like the the screenshot below As you can see the displayed waveform is perfectly stable
19. ht button again to select vertical marker 2 Use the arrow keys to position arae this marker at the exact same location but further to the right of the screen __ Connection layout You have now selected one period or cycle of the NOTES displayed waveform In the lower right corner the unit displays the time between the two markers In most cases this will be 20ms 16 66ms The value displayed is called the period of a waveform i e the time before it repeats itself Lime mark um Now for the frequency the number of periods per second Press and hold the upper right hand button until the menu ap pears When the menu appears release the button and press it again a number of times until time mark is displayed in Connection summary reverse video Next press any arrow key once to change the eden ps mode from time mark to freq mark Release all buttons robe up wait until the unit exits the menu Purpose The purpose of this experiment is to show what single phase rectified AC looks like on a scope screen How 1 Turn on the HPS140 Handheld Pocket Scope see HPS140 manual for How To instructions Look in the lower right corner The readout now displays 2 Place the probe switch x1 x10 to x1 frequency In most cases this will be 50Hz 60Hz 3 Make sure to flip SW1 to the correct position Select 5ms div and 4V div The display wi
20. it does not jump from left to right The circuit responsible for this is the triggering circuit We encourage you to further experiment with your oscilloscope Try looking at vari ous signals from all kinds of sources Just make sure that you respect the maximum How does it work input voltage of your scope 100Vp with probe set to x1 If in doubt begin by setting Take a close look at the left hand side of the screen where the waveform starts You will see a vertical line with a small gap In this gap a slope symbol is displayed This gap determines the trigger point the place where the scope will trigger or will start drawing the waveform on the screen the probe to x10 We do not encourage you perform measurements on live equip ment i e equipment that is connected to the power grid without a transformer These circuits are unsafe Examples of unsafe circuits are some household appli ances old TV sets dimmer circuits switch mode power supplies etc Battery oper ated equipment is usually safe 20 GLOSSARY mn pee eee m omm i eee eee gt m mm mmm mmm 1 Volts div Determines how many volts the signal at the input must swing for the trace to move one division 2 Time div Determines the time the trace needs to scan from the the left hand side to the right hand side of a division 3 Division Imaginary or visible grid on the oscilloscope sc
21. ll show a signal similar to this one p Tree TERRE A little theory With a single diode we can convert an AC voltage to a DC voltage As a diode only conducts the current in one way only one half of the waveform can pass The other half with inverted polarity is blocked As you can see on the screen the trace shows interruptions where the voltage is 0 This is the part of the AC voltage that is blocked by the diode If you move the probe clip from test point 5 and to test point 1 you remove the diode from the circuit and the display shows the complete waveform again Good to know The AC power grid frequency in most parts of the world is 50Hz Good to know Should the rectifier diode be defective then you will see either the complete waveform if the diode is shorted or no waveform at all if the diode is open circuit The US Japan and some parts of Central and South America have 60Hz power 12 13 Experiment 5 Rectified AC dual phase Now check what happens when you flip the switch from single phase to dual phase rectification Connection layout 3 004 Flip the switch back and forward to clearly see the difference between both settings A little theory As you can see the interruptions we have noticed with single phase rectification are gone As opposed to single phase rectification both halves of the sine wave are used Instead of a single diode we use 4 diodes
22. reen It helps estimating signal amplitude and period Period T Duration of one cycle of the AC waveform 1 f Frequency f The number cycles of the AC waveform per second Trace line that is drawn on the screen which represents the signal at the input Amplitude How far does the signal swing in a direction Expressed in mV or V For repetitive signals Vpeak 8 Peak to peak Difference between most positive and most negative swing of the signal 2xVpeak for sinusoidal signals NO oo f AC coupling The oscilloscope only displays the AC component of a signal any DC level is ignored Analog Analog scopes use the incoming signal to deflect an electron beam which scans from left to right on the screen The electron beam leaves an image on the screen which represents the signal you ve applied Analog signals are continuously variable See also Digital Auto setup mode The oscilloscope automatically selects a setting for Volts div and Time div in such a way that one or more periods of signal are displayed correctly Clipping When the top or bottom or both extremes of a signal are cut off clipped e g because the signal cannot swing any further due to power supply limitations An undesired property of amplifiers that are driven beyond their specs DC coupling The oscilloscope displays both the AC and the DC component of a signal Digital Digital scopes perform an analog to digital conve
23. rom 0 to max by turning RV1 At any time the trace will be displayed correctly and it will not go off screen At the lower right hand corner the current Vrms will be correctly displayed Experiment 3 Measuring AC grid frequency and period NOTES Connection layout Connection summary GND clip 2 Probe tip 3 Purpose The purpose of this experiment is to demonstrate the use of the markers to perform on screen measurement of frequency and period How 1 Turn on the HPS140 Handheld Pocket Scope see HPS140 manual for How To instructions 2 Place the probe switch x1 x10 to x1 Press the lower right button this will freeze the screen and turn on the markers The upper right button allows us to toggle between the different markers There are 4 markers two horizontal and two vertical The horizontal markers allow us to measure the amplitude of a displayed signal i e it measures how many volts there are between both markers The vertical markers allow us to measure time between the two markers In order to measure the frequency of a periodic signal we can use the vertical markers and isolate one period of the signal Press the upper right button repeatedly to select vertical marker 1 Next use the arrow keys to position marker 1 on the sine wave as shown AHemora Measuring grid frequency period EREE 11 mera Experiment 4 Rectified AC single phase Press the upper rig
24. rsion on the incoming signal and handle all the calcula tions and displaying in the digital domain Digital signals feature only two fixed levels usually OV and 5V See also Analog Distortion Undesired alteration of a signal due to external causes such as overloaded circuits badly designed circuits etc 21 Noise Undesired random addition to a signal Ripple Unwanted periodic variation of a DC voltage Signal Voltage applied to the input of the oscilloscope The subject of your measurement Sine wave Mathematical function that represents a smooth repetitive oscillation The waveform shown at the start of this glossary is a sine wave Spikes Fast short duration transients in a signal AC voltage AC Alternating Current With AC the flow of the current periodically reverses as opposed to DC where the current flows in one direction An AC source does not have a polarity Bandwidth Usually expressed in MHz It is the frequency at which an applied sine wave will be displayed at an am plitude of around 70 of its original amplitude More expensive scopes feature a higher bandwidth Rule of thumb the bandwidth of an oscilloscope needs to be at least 5 times higher than the frequency of the signal applied to the input of the scope The HPS140 bandwidth goes up to 10MHz DC reference DC measurement is always performed with respect to a ground level so we need to define this ground level If you do not set the DC referen
25. s to show that a scope is also suited to measure DC voltages In general scopes are used to measure AC voltages For DC voltages a multimeter is fine However if you don t have a multimeter at hand you can still perform DC measurements with a scope MAKE SURE THE SCOPE IS SET UP CORRECTLY FOR DC MEASUREMENTS How 1 Place the probe switch x1 x10 to x1 2 Turn on the HPS140 Handheld Pocket Scope it will turn on in auto set mode Auto setup will also work for DC measurements There are 3 important settings that need to be performed for correct DC measurement e DC input coupling e DC readout e DC reference DC input coupling Input coupling needs to be set to DC When set to AC the scope will block any DC signal so we won t be able to perform DC measurements At start up the unit is automatically set to DC coupling Next we will set the readout in the bottom right hand corner to DC Press and hold the upper right hand button until the menu appears Release the button and press it again a number of times until the readout setting is highlighted 123 appears in the lower left hand corner Next press any of the arrow keys repeatedly until Vdc is displayed Wait for the unit to return to scope screen TEE OH It now displays the measured DC voltage in the lower right hand corner AWE Fir TM Set the DC reference AUTO time GHD To set the DC reference set t
26. tes the smallest change of the input signal that makes the trace move up or down on the screen Usually expressed in mV The HPS140 sensitivity is 0 1mV Slope It determines where the scope will trigger This can be on the rising or on the falling slope of the signal slope 1 falling slope Vrms The rms voltage of an AC source represents the required DC voltage to generate the same amount of heat in a resistor as the AC source would do For sinusoidal signals Vrms Vpeak sqrt 2 22 Ween Do not let its size fool you This Pocket size PC oscilloscope and function Oscilloscope packs a lot of power in generator This small box contains a world a tiny box Now you can really take a f measuring tools From generating powerful oscilloscope everywhere gnals to a powerful 2 channel oscillo handy bode plot function No ed for a power supply since the unit is wered over USB Powerful compact and USB connectivity this sums up the features of this oscilloscope The large keyboard and bright LCD makes this unit a breeze to use combine this with great specifications and you complete function generator in pocket wonder how you ever managed format Now you can take test signals on the without it move 3 waveforms can be selected Set the output voltage or frequency and select signal waveform using the on the Screen menu A powerful sweep function is also included O SK7 PCGU1000 2MHz
27. the signal is passed on to the scope without attenuation When set to x10 the signal is divided by 10 so the signal that is seen by the scope is ten times smaller than it acuatally is This allows you to measure higher voltages without damaging your scope Connecting the probe Setting up the board The board requires a 9VAC Alter nating Current adaptor e g Velleman PS905AC 230VAC A DC adaptor instead of an AC adaptor will not damage the board but most experiments will not work correctly Connect the adaptor at the left hand side of the board and plug in the adaptor Generator Board Ex A i ac i e los eges ae Ies Once powered the LEDs LD2 amp LD3 should blink alternately The board is now ready to perform experiments Velleman EDUOG 6 Exp 1 measuring AC voltage Exp 2 Adjustable AC voltage advantages of the auto setup function 7 Experiment 1 Measuring AC voltage Experiment 2 Adjustable AC voltage advantages of the auto setup function Connection layout S1 al Generator Board os E F NOTES Connection layout NOTES TOS lt Connection summary summa GND clip 2 7 Probe tip 1 GND clip 2 Probe tip 3 Purpose Purpose Tus purpose or mis The purpose of this experiment is to show the advantages of the auto setup function to measure
28. the AC part of the signal the DC part will be blocked Make sure it is still in auto setup mode If you look at the screen below and your scope screen you will see a kind of sawtooth waveform this is the ripple volt Connection summary age that rides on top of your DC voltage During the rising GND clip 4 edge the power supply charges the capacitor during the Probe tip 6 falling edge the capacitor supplies current to the circuit If more current is drawn from the supply the ripple will be higher as the capacitor will be drained Purpose more so it will not be able to keep the output as steady as it would with a small load The purpose of this experiment is to show what smoothed and unsmoothed DC looks like on a scope screen and how a scope can help you to determine the quality of your DC supply How can we reduce the ripple Try flipping SW1 for single phase to dual phase rectification A little theory and watch the screen Check the lower right hand corner EC In the previous experiments we have used or more diodes to convert AC voltage into a DC volt It displays the rms ripple voltage age The result was OK but far from perfect Flip the switch back and forward It is clear that ripple is 1 ye 1 4 Run reduced when dual phase rectification is used Why Because it was still far from the flat line one would expect when measuring a perfe

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