Electronics Workbench tutorials
Introduction
Electronics Workbench (EWB) is a simulation package for electronic circuits. This allows you to design and analyze circuits without using breadboards, components or actual real instruments. EWB's click-and-pull circuit operation makes editing quick and easy. You can changeparameters and circuit components on the fly, which makes "what-if"straight foreward analysis.
This tutorial is intended as a quick introduction to the basic EWBfeatures. It first takes you through the steps to put the fundamentalcircuits together and analyze the function using the instrument. thethe end of the tutorial consists of two exercises that attempt to describeEWB strength. It also tries to encourage you to apply "what if" approach to designing circuits. This will greatly help your understanding ofEWB electronically if you use it interactively: Making changes to thecircuit you are working on, observe the effect of this change,and try to understand them. EWB puts very little constraint onparameters so do not be afraid, do not just change things by 10%, trywhat happens when you change them with a few commands in themagnitude.
EWB scheme Direct printing and graphics is usually notproduce satisfactory results, and leads to tremendous waste of paper. Thisbetter to combine the results of EWB by copying to the clipboarduse the copy as a bitmap command, and then insert it intosomething like a word document.
To open click on its icon EWB. Initially you will see a blankcircuit window and two toolbars, the toolbar circuit with a common filemanagement, editing and graphics tools, and the Bin toolbar Part ofwhere you can choose various circuit elements, and instruments.The following will guide you on your first attempt to simulate the circuit.
Build and test the circuit
In this part oftutorial, you will buildsimple voltage DCdivider circuit is shownbelow.
Figure 1. A resistive voltage divider
Step 1. Place the components on the circuit window
To build the circuit, you need a battery, two resistors and groundconnections. Assemble the components for the circuit.1. Select File / New to open a new circuit file.
2. Click on the Parts Bin toolbar. Basic toolbar should appear.3. Pull the two resistors from the toolbar to the window circuit.resitorTo keep open Basic toolbar, drag it onto the circuit window.Otherwise, it will shut down after you pull the item from it, and you mustreopen it for each resistor.4. Sources on the toolbar to move to the Parts Bin. Click and toolbarcontains a battery and the ground should appear. Drag them to thecircuit window. .
Step 2. Set the circuit elementsYou can change the orientation of the circuit elements either byrotating them or flipping them over. To do this, select the circuit elementsand either click on the playing standard / sandals icon on the toolbar, orselect the desired operating under Circuit. In this case you want to playtwo resistors.1. Select both well CTRL + click, or by dragging the mouse over them.2. Choose your favorite way to rotate 90 degrees.Note that the circuit elements are selected will be highlighted / change color.
Step 3. Wire components togetherMost components have a short line pointing outwards, whichterminal. To wire the components together you have to make the cablebetween components.1. Move the pointer to the terminals on the battery. if youare in the right position to make a connection, the black dot appears.Now pull up resistor on the wire. Once again the black dotappears, and the wire is locked into position.2. Wire the remaining components in the same way. You should end upwith something like this:
Initially you may not look very pretty wired. However, after makingconnection, you can move around without any cables and componentsbreaking the connection.
Step 4. Set the value to the componentInitially, each component appears with a pre-set value, the default,for example, the battery voltage is set to 12 V. You can change all the componentsvalues in accordance with your application.1. Double-click on the component.2. select VALUE3. Change its value.4. Click OK.
Step 5. Save your circuitSave your work often!1. Choose File / Save.2. Continue with the normal way to save the file.
Step 6. Connect the voltmeter
To measure the voltage in your circuit, you can use one or morevoltmeter.1. Pull the voltmeter from the toolbar to the window circuit indicators.2. Pull the cord from the voltmeter to the point in your circuitbetween which you want to measure voltage.3. Enable circuit series by clicking the power switch at the topEWB-right corner of the window.Note that the ground connection does not play a certain role in thismeasurements. Voltmeter is not connected to a reference point. Thisfunction very much like a handheld multimeter in the lab. You canmeasure the voltage difference between the pair of points on the circuit.
Step 7. Make changes and additions
You now have a very simple circuit but it works. take thisopportunity to make some changes and additions.1. Add the ammeter to the circuit to measure current throughresistor.2. Change the value of the resistor, and observe changes incurrent and voltage.Ammeter can be connected with a position on the wire throughthat you want to measure the current. EWB will automatically makethe right connections. If you are not sure that this is done correctly, pullammeter, the cable must move with it.
Using the main instrument
EWB incorporates a number of instruments, such as
oscilloscope and function generator. The following providesintroduction to these two instruments. To investigate briefly the functiongenerator, build the circuit below.
Figure 2. The function generator with bargraph displays.
Function generator1. Pull over to the window function generator circuit.2. Double-click on the function generator. Now you can change itssettings, such as waveform, amplitude signal and the signalfrequency.3. The function generator has three terminals, "-", "common" and "+".Connect common ground terminal.4. Getting two red probe of the toolbar indicator. Wire them to the "+"and "-" terminal, and activate the circuit.
You should now have two flashing red lights. To get a little moreinformation we will attach the second type of indicator.5. Getting two bargraph displays the decoded form of the toolbar indicator.6. Wire one terminal of each of the bargraph indicator to the ground, andthe other terminal to the "+" and "-" terminal of the functiongenerator.7. Experiment by changing the wave form and frequency of the signalgenerator.
oscilloscope
Oscilloscope is a much more powerful tool than the bargraphindicator or even of a voltmeter. It can show time dependencesignals in your circuit. The EWBoscilloscope provides enoughclose approximation of the real.It has two independent inputschannels, A and B, input toexternal trigger and groundconnections.
Figure 3. EWB oscilloscope icon with its terminals.
To see the output from the signal generator, you can addoscilloscope to the circuit you just made.1. Pull the oscilloscope to the circuit window, and double-click on it.Oscilloscope has four terminals, for two independent inputchannel, trigger input and ground connections. inputunderstanding with respect to the ground voltage line! As long as there is inat least one ground terminal attached to your circuit, do not needto connect the oscilloscope ground. We will discuss howoscilloscope is triggered in the classroom. At this point, leaving the triggeron auto.
2. Connect channel A to output "+" function generator, andactivate the circuit. You should now have a sine wave at youoscilloscope screen
3. Making drastic changes in signal amplitude and frequency, andadjust sensitivity and time base settings like that you stillretain easily interpretable picture of the waveform onoscilloscope screen. It may be necessary to occasionally turn onsimulation.
Figure 4. Using an oscilloscope to investigate the signal fromfunction.
4. Change the offset to the function generator to the value of the orderamplitude. This adds a constant voltage to the signal. You will seetrace on the oscilloscope move up (or down). You have two choicesto move it back to the center.
5. Change the position of "y" as a track back to the center.It can always be done during the offset is not too large. (Mostoscilloscope can not generate internally offset a much largerfull-scale range of the screen.)6. Change the "y-position" back to zero, and select "AC" as the inputmode coupling. In this mode the DC component of the signalremoved. EWB oscilloscope is very good, but realinstruments have difficulty distinguishing between the DC and veryslowly oscillating signals. In practice, avoid AC input mode forless than 100 Hz signal frequency.
To get a larger picture of the oscilloscope, try the developing world. onYou'll find an expanded view of two vertical line cursor. With this movearound you can measure time and amplitude of points on the displayedtrail.
two exercises
The following exercise is intended to demonstrate the power of EWB. infirst you can learn what happens when the LRC circuit is driven withsquare wave. Even the simple circuit showing the various behaviors,depending on component values and frequency drives. EWB makeallows for the study was at least qualitatively. secondexercise gives you the opportunity to build a simple circuit withoutknow a lot about how things would work. This is one of the mainadvantage of the simulation program. Without the many mathematical or investmenton the hardware you can try new ideas and adapt them to the reality in whichrequired.
LRC circuit
Assemble the circuit shown below, and activate. Once youachieve something similar to fig. 4, change the value of dampingresistor. Look at the value of 100W 100kW. Can you explain yourobservation?
Figure 5. Driving LRC circuit with a square wave.
Set the damping resistor to 100W. Now scan function generatorfrequencies from 15 Hz to 25 Hz in 1 Hz steps. The behavior of
circuit seems to change dramatically for very small changes infrequency. Try to figure out why this happens.
In this exercise we have used an external trigger to stabilizeoscilloscope picture. You may still feel uncomfortable to read scope.Try the following. Click on Analysis / Analysis option (Ctrl Y). Click onInstrument tab, and select under Oscilloscope "Pause after each screen."You can then use the Continue button to go through the simulation oneoscilloscope screen at a time. This may require a number of frames to achievesteady state behavior.
AC DC conversion áSomehow you have to take the information that there is a series ofelements that pass current in one direction and blocks acrossone. They go by the name of the diode. It strikes you that this can be usefulto convert AC voltage, perhaps from a transformer, for DC voltage. tosee if this really will make you a place you putollowing the circuit.
Figure 6. Using diodes to fix the sine wave. Note that wehave used the Y-position offset in scope to separate the Aand B channel footprint.
Apparently there is some truth to the story, you only have a positiveresistor voltage, when the input voltage goes negativeoutput voltage is zero. However, you realize that this is not quite what youwant. What you are after is a fairly constant voltage, andcertainly not something that is zero half the time. You are now sufferingsuddenly flash back to your introductory physics course. there isThis capacitor is mentioned. It should be able to store charge. mayThis can be used to keep the voltage rise during the perioddiode blocks the flow. So the next step is to place the capacitor intoThe problem is, you do not know how big it should be. To save money andspace you want to minimize the capacitance. In this case began with 10mFand change the value to see what you can get away with.
Figure 7. Smoothing rectified sine wave using a capacitor.
With a large enough capacitor that you can get a DC voltage withvery small ripple. However, the capacitance you need is a little big,and voltage of 17V. As it happens, you really want somethingclose to 8V. A colleague suggested that you use a zener diode to fix this.You're not too sure, but you have the impression that this is some sort ofvoltage stabilizer. So you pick a zener diode from the toolbar and trysome look configurations that make sense. Maybe something like this.
Figure 8. Using a zener diode to obtain the desired voltage. incircuit diagram that you see labeled as BZV49-zenerC8V2. To get this one particular you have to double click ongeneric zener, and go through the list of "real" zener diodeavailable.
This does not work properly. You see that for part of the time youhas a constant voltage from the desired value, but in between there is a largedips. You do not understand, so you use the oscilloscope toinvestigate what happened. Leave the channel B where, but move the channelA to measure the voltage across the capacitor. From oscilloscopeit's now pretty clear picture of what is happening. During the voltage on
14
capacitor is greater than 8.2V zener works fine. However, whencapacitor discharges below 8.2 V, zener diode can not make it,and stopped to stabilize the voltage. To make work the circuit, the voltage oncapacitor must be greater than 8.2V all the time. In section (2) You seethat this requires a large capacitor. You can now increasecapacitance so has the only correct value.
Figure 8. Using an oscilloscope to check the various voltagescircuit. To make a comparison between channel A and B
easier, you have to set sensitivity (y-scale) for bothchannels to the same value, and y-positions to zero.
After adjusting the value of the capacitor, you might be interested in howactual DC voltage constant. On a scale 5V/div you do notnotice any irregularities. When you try to go to a higher sensitivity, tracemoving from the screen. Because you are only interested in the oscillationapproximately constant value of 8V, you can switch one channel toAC mode. This eliminates the DC and allows to seesmall features.
Figure 9. Checking for the size of the ripple on the DC voltage.Note that here we have been connected to both lines the samepoint. Channel, set to DC-5V/div, DC voltage monitor,Channel B, is set to AC-10mV/div see a small ripple.Because it is difficult to trigger the voltage is almost constant, wehave used an external input to trigger the trigger directly oninput sine wave.
Congratulations! You have mastered a very usefulsoftware. Keep in mind that while EWB is intended for electronicscircuit, thermal and mechanical problems that can be mapped toequivalent electrical circuit, and simulation / resolved by using this software.
Introduction
Electronics Workbench (EWB) is a simulation package for electronic circuits. This allows you to design and analyze circuits without using breadboards, components or actual real instruments. EWB's click-and-pull circuit operation makes editing quick and easy. You can changeparameters and circuit components on the fly, which makes "what-if"straight foreward analysis.
This tutorial is intended as a quick introduction to the basic EWBfeatures. It first takes you through the steps to put the fundamentalcircuits together and analyze the function using the instrument. thethe end of the tutorial consists of two exercises that attempt to describeEWB strength. It also tries to encourage you to apply "what if" approach to designing circuits. This will greatly help your understanding ofEWB electronically if you use it interactively: Making changes to thecircuit you are working on, observe the effect of this change,and try to understand them. EWB puts very little constraint onparameters so do not be afraid, do not just change things by 10%, trywhat happens when you change them with a few commands in themagnitude.
EWB scheme Direct printing and graphics is usually notproduce satisfactory results, and leads to tremendous waste of paper. Thisbetter to combine the results of EWB by copying to the clipboarduse the copy as a bitmap command, and then insert it intosomething like a word document.
To open click on its icon EWB. Initially you will see a blankcircuit window and two toolbars, the toolbar circuit with a common filemanagement, editing and graphics tools, and the Bin toolbar Part ofwhere you can choose various circuit elements, and instruments.The following will guide you on your first attempt to simulate the circuit.
Build and test the circuit
In this part oftutorial, you will buildsimple voltage DCdivider circuit is shownbelow.
Figure 1. A resistive voltage divider
Step 1. Place the components on the circuit window
To build the circuit, you need a battery, two resistors and groundconnections. Assemble the components for the circuit.1. Select File / New to open a new circuit file.
2. Click on the Parts Bin toolbar. Basic toolbar should appear.3. Pull the two resistors from the toolbar to the window circuit.resitorTo keep open Basic toolbar, drag it onto the circuit window.Otherwise, it will shut down after you pull the item from it, and you mustreopen it for each resistor.4. Sources on the toolbar to move to the Parts Bin. Click and toolbarcontains a battery and the ground should appear. Drag them to thecircuit window. .
Step 2. Set the circuit elementsYou can change the orientation of the circuit elements either byrotating them or flipping them over. To do this, select the circuit elementsand either click on the playing standard / sandals icon on the toolbar, orselect the desired operating under Circuit. In this case you want to playtwo resistors.1. Select both well CTRL + click, or by dragging the mouse over them.2. Choose your favorite way to rotate 90 degrees.Note that the circuit elements are selected will be highlighted / change color.
Step 3. Wire components togetherMost components have a short line pointing outwards, whichterminal. To wire the components together you have to make the cablebetween components.1. Move the pointer to the terminals on the battery. if youare in the right position to make a connection, the black dot appears.Now pull up resistor on the wire. Once again the black dotappears, and the wire is locked into position.2. Wire the remaining components in the same way. You should end upwith something like this:
Initially you may not look very pretty wired. However, after makingconnection, you can move around without any cables and componentsbreaking the connection.
Step 4. Set the value to the componentInitially, each component appears with a pre-set value, the default,for example, the battery voltage is set to 12 V. You can change all the componentsvalues in accordance with your application.1. Double-click on the component.2. select VALUE3. Change its value.4. Click OK.
Step 5. Save your circuitSave your work often!1. Choose File / Save.2. Continue with the normal way to save the file.
Step 6. Connect the voltmeter
To measure the voltage in your circuit, you can use one or morevoltmeter.1. Pull the voltmeter from the toolbar to the window circuit indicators.2. Pull the cord from the voltmeter to the point in your circuitbetween which you want to measure voltage.3. Enable circuit series by clicking the power switch at the topEWB-right corner of the window.Note that the ground connection does not play a certain role in thismeasurements. Voltmeter is not connected to a reference point. Thisfunction very much like a handheld multimeter in the lab. You canmeasure the voltage difference between the pair of points on the circuit.
Step 7. Make changes and additions
You now have a very simple circuit but it works. take thisopportunity to make some changes and additions.1. Add the ammeter to the circuit to measure current throughresistor.2. Change the value of the resistor, and observe changes incurrent and voltage.Ammeter can be connected with a position on the wire throughthat you want to measure the current. EWB will automatically makethe right connections. If you are not sure that this is done correctly, pullammeter, the cable must move with it.
Using the main instrument
EWB incorporates a number of instruments, such as
oscilloscope and function generator. The following providesintroduction to these two instruments. To investigate briefly the functiongenerator, build the circuit below.
Figure 2. The function generator with bargraph displays.
Function generator1. Pull over to the window function generator circuit.2. Double-click on the function generator. Now you can change itssettings, such as waveform, amplitude signal and the signalfrequency.3. The function generator has three terminals, "-", "common" and "+".Connect common ground terminal.4. Getting two red probe of the toolbar indicator. Wire them to the "+"and "-" terminal, and activate the circuit.
You should now have two flashing red lights. To get a little moreinformation we will attach the second type of indicator.5. Getting two bargraph displays the decoded form of the toolbar indicator.6. Wire one terminal of each of the bargraph indicator to the ground, andthe other terminal to the "+" and "-" terminal of the functiongenerator.7. Experiment by changing the wave form and frequency of the signalgenerator.
oscilloscope
Oscilloscope is a much more powerful tool than the bargraphindicator or even of a voltmeter. It can show time dependencesignals in your circuit. The EWBoscilloscope provides enoughclose approximation of the real.It has two independent inputschannels, A and B, input toexternal trigger and groundconnections.
Figure 3. EWB oscilloscope icon with its terminals.
To see the output from the signal generator, you can addoscilloscope to the circuit you just made.1. Pull the oscilloscope to the circuit window, and double-click on it.Oscilloscope has four terminals, for two independent inputchannel, trigger input and ground connections. inputunderstanding with respect to the ground voltage line! As long as there is inat least one ground terminal attached to your circuit, do not needto connect the oscilloscope ground. We will discuss howoscilloscope is triggered in the classroom. At this point, leaving the triggeron auto.
2. Connect channel A to output "+" function generator, andactivate the circuit. You should now have a sine wave at youoscilloscope screen
3. Making drastic changes in signal amplitude and frequency, andadjust sensitivity and time base settings like that you stillretain easily interpretable picture of the waveform onoscilloscope screen. It may be necessary to occasionally turn onsimulation.
Figure 4. Using an oscilloscope to investigate the signal fromfunction.
4. Change the offset to the function generator to the value of the orderamplitude. This adds a constant voltage to the signal. You will seetrace on the oscilloscope move up (or down). You have two choicesto move it back to the center.
5. Change the position of "y" as a track back to the center.It can always be done during the offset is not too large. (Mostoscilloscope can not generate internally offset a much largerfull-scale range of the screen.)6. Change the "y-position" back to zero, and select "AC" as the inputmode coupling. In this mode the DC component of the signalremoved. EWB oscilloscope is very good, but realinstruments have difficulty distinguishing between the DC and veryslowly oscillating signals. In practice, avoid AC input mode forless than 100 Hz signal frequency.
To get a larger picture of the oscilloscope, try the developing world. onYou'll find an expanded view of two vertical line cursor. With this movearound you can measure time and amplitude of points on the displayedtrail.
two exercises
The following exercise is intended to demonstrate the power of EWB. infirst you can learn what happens when the LRC circuit is driven withsquare wave. Even the simple circuit showing the various behaviors,depending on component values and frequency drives. EWB makeallows for the study was at least qualitatively. secondexercise gives you the opportunity to build a simple circuit withoutknow a lot about how things would work. This is one of the mainadvantage of the simulation program. Without the many mathematical or investmenton the hardware you can try new ideas and adapt them to the reality in whichrequired.
LRC circuit
Assemble the circuit shown below, and activate. Once youachieve something similar to fig. 4, change the value of dampingresistor. Look at the value of 100W 100kW. Can you explain yourobservation?
Figure 5. Driving LRC circuit with a square wave.
Set the damping resistor to 100W. Now scan function generatorfrequencies from 15 Hz to 25 Hz in 1 Hz steps. The behavior of
circuit seems to change dramatically for very small changes infrequency. Try to figure out why this happens.
In this exercise we have used an external trigger to stabilizeoscilloscope picture. You may still feel uncomfortable to read scope.Try the following. Click on Analysis / Analysis option (Ctrl Y). Click onInstrument tab, and select under Oscilloscope "Pause after each screen."You can then use the Continue button to go through the simulation oneoscilloscope screen at a time. This may require a number of frames to achievesteady state behavior.
AC DC conversion áSomehow you have to take the information that there is a series ofelements that pass current in one direction and blocks acrossone. They go by the name of the diode. It strikes you that this can be usefulto convert AC voltage, perhaps from a transformer, for DC voltage. tosee if this really will make you a place you putollowing the circuit.
Figure 6. Using diodes to fix the sine wave. Note that wehave used the Y-position offset in scope to separate the Aand B channel footprint.
Apparently there is some truth to the story, you only have a positiveresistor voltage, when the input voltage goes negativeoutput voltage is zero. However, you realize that this is not quite what youwant. What you are after is a fairly constant voltage, andcertainly not something that is zero half the time. You are now sufferingsuddenly flash back to your introductory physics course. there isThis capacitor is mentioned. It should be able to store charge. mayThis can be used to keep the voltage rise during the perioddiode blocks the flow. So the next step is to place the capacitor intoThe problem is, you do not know how big it should be. To save money andspace you want to minimize the capacitance. In this case began with 10mFand change the value to see what you can get away with.
Figure 7. Smoothing rectified sine wave using a capacitor.
With a large enough capacitor that you can get a DC voltage withvery small ripple. However, the capacitance you need is a little big,and voltage of 17V. As it happens, you really want somethingclose to 8V. A colleague suggested that you use a zener diode to fix this.You're not too sure, but you have the impression that this is some sort ofvoltage stabilizer. So you pick a zener diode from the toolbar and trysome look configurations that make sense. Maybe something like this.
Figure 8. Using a zener diode to obtain the desired voltage. incircuit diagram that you see labeled as BZV49-zenerC8V2. To get this one particular you have to double click ongeneric zener, and go through the list of "real" zener diodeavailable.
This does not work properly. You see that for part of the time youhas a constant voltage from the desired value, but in between there is a largedips. You do not understand, so you use the oscilloscope toinvestigate what happened. Leave the channel B where, but move the channelA to measure the voltage across the capacitor. From oscilloscopeit's now pretty clear picture of what is happening. During the voltage on
14
capacitor is greater than 8.2V zener works fine. However, whencapacitor discharges below 8.2 V, zener diode can not make it,and stopped to stabilize the voltage. To make work the circuit, the voltage oncapacitor must be greater than 8.2V all the time. In section (2) You seethat this requires a large capacitor. You can now increasecapacitance so has the only correct value.
Figure 8. Using an oscilloscope to check the various voltagescircuit. To make a comparison between channel A and B
easier, you have to set sensitivity (y-scale) for bothchannels to the same value, and y-positions to zero.
After adjusting the value of the capacitor, you might be interested in howactual DC voltage constant. On a scale 5V/div you do notnotice any irregularities. When you try to go to a higher sensitivity, tracemoving from the screen. Because you are only interested in the oscillationapproximately constant value of 8V, you can switch one channel toAC mode. This eliminates the DC and allows to seesmall features.
Figure 9. Checking for the size of the ripple on the DC voltage.Note that here we have been connected to both lines the samepoint. Channel, set to DC-5V/div, DC voltage monitor,Channel B, is set to AC-10mV/div see a small ripple.Because it is difficult to trigger the voltage is almost constant, wehave used an external input to trigger the trigger directly oninput sine wave.
Congratulations! You have mastered a very usefulsoftware. Keep in mind that while EWB is intended for electronicscircuit, thermal and mechanical problems that can be mapped toequivalent electrical circuit, and simulation / resolved by using this software.
No comments:
Post a Comment
EMAIL ADDRESS MUST BE INCLUDED.