Unformatted Attachment Preview
Electronic Circuit & Systems Design H7076
2017
Electronic Circuit & Systems Design
Laboratory Handbook
Part 2: Experiment A
Bipolar Transistor
Content:
Transistor Characteristic
Transistor as switch
Amplifier
Remember that you should simulate all the circuits to determine the values for passive components in
the lab sessions (or any other time in Richmond), and do all the measurements in the practical sessions.
The ELVIS boards will be used in the laboratory sessions, here you should build all the circuits using
discrete devices and select components base on the previously done simulations. Characterization of
these circuits can be done use the virtual ELVIS board instruments or the table top equipment.
Aims
1.
2.
3.
To become familiar with the characteristics of a single transistor, to extract its performance
parameters, and to compare the measured values with the values given in the data sheet.
To gain an understanding of transistor operation in simple single stage switching and amplifier
circuits.
To acquire a basic knowledge of circuit simulation and virtual instrumentation techniques
(using Multisim) by comparing these with experiment
This experiment is based on a BC107/8/9 bipolar transistor
You must simulate your circuits using Multisim before attending the practical session (there is enough time
in the lab sessions, but you can work on the simulation at any time using the PCs in Richmond). You will
lose marks if a full range of simulations are not included in your final report.
You should note that while circuit simulation is a useful and powerful tool it is only a part of the design
procedure. You will still be required to calculate and justify the component values you have chosen.
However, the ability to rapidly evaluate your design by simulation and if necessary modify it to achieve the
required results is increasingly the procedure used professionally. Note that the transistor chosen for this
experiment is one of the devices in the Multisim library, and this should be selected for your simulations.
1/5
Electronic Circuit & Systems Design H7076
2017
I. DC Transistor characteristic
Tasks:
1. Download the datasheet and familiarize yourself with the transistor.
2. Simulate the output characteristic of the transistor, use appropriate bias currents and voltages,
and at least 3 different base currents.
3. Connect the BC109 (or BC107 or BC108) to the ELVIS board and measure the transistor output
characteristic, use the same currents and voltages as in your simulation
4. Compare the measured and simulated characteristic with the manufacturer’s data sheet.
5. Draw or print the transistor characteristics, annotated the graph and graphically extract the output
resistance of the device.
6. Estimate the β ratio of the transistor using the measured characteristic and compare all values to
the datasheet.
II. Transistor as switch
The purpose of this experiment is to switch the transistor between the extremes of saturation and cut-off.
Based on the characteristic curves for the BC109 (or BC107 or BC108), choose suitable component values
for the circuit shown in Fig. 1 (calculations), simulate the circuit using Multisim, and construct it on the NIELVIS board.
Figure 1: Transistor as switch.
When Vin =5 V the transistor should be fully ON and when Vin = 0 V the transistor will be fully OFF.
Consider the maximum ratings for the LED and the transistor in your design.
Tasks:
1. When the transistor is ‘ON’, use the digital voltmeter (DVM) to simulate and measure:
a. the voltage across the transistor
b. the voltage across the collector resistor (and hence calculate the current)
c. the voltage across the base resistor (calculate the current)
2. Repeat 1) when the transistor is ‘OFF’.
3. From these values calculate the dissipated power in both the ‘ON’ and ‘OFF’ states.
4. Compare the power dissipated in the LED, collector resistor and transistor when in the ‘ON’ state
and when in the ‘OFF’ state.
2/5
Electronic Circuit & Systems Design H7076
2017
III. Common emitter amplifier
A common emitter amplifier (Fig. 2) should be designed to operate at midpoint bias. Use the characteristics
in the data sheet to determine the bias point and design an appropriate voltage divider bias network.
Simulate the circuit, and build it on the NI Elvis board. Choose appropriate component values to provide a
voltage gain of 80. Use midpoint biasing to design the circuit, and follow the rules specified in the lecture.
The collector bias current should be ≈1% of the absolute maximum collector current given in the datasheet.
Figure 2: Common emitter amplifier
Choose appropriate input and output coupling capacitors to allow the circuit to function properly down to
≈20 Hz. (It may be best to use small electrolytic capacitors, consider this option).
Tasks:
1. Show calculations for all components.
2. Estimate the input and output impedances of the amplifier you have designed.
3. Simulate and measure the collector-emitter voltage (VCE)
•
Does this agree with your design? If not, explain why.
4. Simulate and measure the collector current for the quiescent state before you apply a signal.
•
Does this agree with your design? If not, explain why.
5. Simulate and measure the gain of the amplifier for different frequencies, by comparing Vout with
Vin using two channels of the oscilloscope. Select a suitable frequency range, and make sure the
cutoff frequency of the amplifier can be extracted. Record the measurement in your logbook
(about 15 spot frequency measurements should be sufficient, with logarithmic spacing).
•
Plot the results. Create a Bode plot (Gain in dB vs frequency) with appropriate axis and
scaling.
6. Add a suitable value bypass capacitor in parallel with the emitter resistor and repeat the gain
simulations and measurements.
•
Explain how you arrived at your choice of capacitor value (calculations!)
•
Plot the results on the same graph
•
Explain the differences in amplifier performance.
3/5
Electronic Circuit & Systems Design H7076
2017
Report
Your mark will only be determined based on your report. Make sure you submit a complete and concise
report. Also consider the comment concerning the assessment given in the Laboratory Handbook Part 1.
The following points are very important:
You have to include all your results (from calculations, simulations, and measurements).
You have to discuss your results
Use the Word or LATEX template available on Study Direct
The complete report including cover page, references, but excluding the self-assessment should
not be longer than 10 pages
Perform a realistic self-assessment as described at the end of this document. To do so you have to
refer to the marking scheme attached to this document (and available on Study Direct). Based on
the masking scheme judge your report against every criterion specified in the marking table (e.g.
by highlighting the corresponding field). Afterwards calculate the mark you think you deserve for
your report (this will not necessarily be your final mark!)
Self-assessment
A realistic self-assessment has to be done, and included into your report. The self-assessment is worth
10% of the final mark! The self-assessment does not contribute to the page count towards the page limit
of 10 pages.
The assessment criteria for this report are given on page 5. A corresponding word and pdf file is also
available on Study Direct.
Consider the following:
Judge your report against every criterion.
Clearly indicate how you judge your report.
Make sure the marks you give yourself are reasonable.
Calculate the resulting mark you think you deserve.
You can use the provided marking scheme also to optimize your report and hence your mark.
4/5
Electronic Circuit & Systems Design H7076
Weight
Simulation
2017
Criteria
Mark
0%
18%
35%
40%
60%
You did set up the simulation, and there are
some measurements, but it is not clear what the
base current is. A better mark would require the
following: Simulation results and a nice graph of
the output characteristic for multiple base
currents, a calculation of the base currents, and
some effort concerning the extraction of the
performance parameters (gain, output
resistance, and the transition between the
linear and the active region)
You did set up the simulation, and there are some
results, but they are not complete.
A better mark would require the following:
Simulation results and a nice graph of the output
characteristic for multiple base currents, a
calculation of the base currents, and some effort
concerning the extraction of the performance
parameters (gain, output resistance, and the
transition between the linear and the active
region)
You simulated a meaningful output characteristic, and presented the
results in an understandable way. Unfortunately the extraction of the
performance parameters (gain, output resistance, and the transition
between the linear and the active region) is incomplete.
11%
Simulation I:
Simulation of the
transistor DC
characteristic
No simulation
at all.
You tried to set up the
simulation, but there are
no results.
10%
Simulation II:
Simulation of the
transistor as
switch to turn on
a LED
No simulation
at all.
You tried to set up the
simulation, but there are
no results.
You designed a usable circuit and demonstrated
switching operation, unfortunately it is not clear
how you selected the resistor values.
No simulation
at all.
You tried to set up the
simulation and to calculate
the values of the required
resistors, but there are no
usable results.
You tried to set up a circuit which looks OK, but
there is measurement showing any gain
You calculated values for all resistors, your
simulation somehow works and you
demonstrated that there is gain. A better mark
would require the following: Simulation results
and a nice graph of the frequency response for at
least 15 different well selected frequencies, a
calculation of the coupling capacitors, calculation
of the bypass capacitor (incl. associated
simulation results) and some effort concerning
the performance parameter extraction (gain, cutoff frequency) from the Bode plot.
0%
18%
35%
40%
You tried to connect the
transistor to the board, but
there are no usable results.
You did set up a circuit on the ELVIS board. This
circuit looks basically fine, but your
measurements do not show the typical base
current and the collector-emitter voltage
dependency of the emitter current. At the same
time you should invest more effort in presenting
your results, extracting the important
performance parameters (gain, output
resistance, quantification of the active region),
and discussing the results. Also comparing the
measured results to the data sheet and your
simulation is an important point.
14%
Simulation III:
Simulation of a
common emitter
amplifier
Measurement
14%
13%
18%
Measurement I:
Measurement of
the transistor DC
characteristic
using the ELVIS
board
Measurement II:
Using the
transistor as
switch to control
a LED on the
ELVIS board
Measurement
III:
Building a
common emitter
amplifier on the
ELVIS board.
Report
No effort at
all.
No effort at
all.
You tried to control the LED
using the transistor using
the ELVIS board, but there
are no usable results.
Very good simulation, this part includes all the required simulation
results, a nice graph, the extraction of all or nearly all performance
parameters (gain, output resistance, and the transition between the
linear and the active region). Additionally, you compared your results
to the data sheet and discussed them.
This is a very good design and simulation which includes all required
currents and voltages, and a calculation of the efficiency of the
simulated circuit
You designed and simulated an amplifier with gain close to the desired
value, calculated values for the coupling capacitors, as well as the input
and output impedances and presented your results in a nice way.
Unfortunately your work on the bypass capacitor and the discussion
are not sufficient.
You designed and simulated an amplifier with the desired gain,
calculated the coupling capacitors, and presented your results in a nice
way. Additionally, you included all the required results concerning the
bypass capacitor. However the discussion can be improved.
Very nice work including all the calculations, and simulations. You also
presented your results in a very understandable way, and extracted
and discussed all the important parameters.
OR:
You designed and simulated an amplifier with gain close to the desired
value, calculated values for the capacitors, and showed an increase of
the gain if a bypass capacitor is used. Unfortunately your discussion is
not sufficient. And you have to improve the way you present the
results. Unfortunately your discussion is not sufficient. And you have to
improve the way you present the results.
OR:
You designed and simulated an amplifier with the desired gain,
calculated the coupling capacitors, and presented your results in a very
good way. Also the discussion is appropriate.
Nevertheless, a detailed description of the configuration using a
emitter bypass capacitor is missing.
OR:
Very nice work including all the calculations, and simulations. Whereas
also the internal emitter resistance was considered.
Additionally the important parameters wave been determined and
discussed.
80%
100%
60%
You measured the transistor output characteristic for multiple different
base currents, and presented the results in an understandable way. You
also invested some effort in comparing your measurement results to
the simulated results. Unfortunately the extraction of the performance
parameters (gain, output resistance, and the transition between the
linear and the active region) and the discussion is incomplete.
OR:
You measured the transistor output characteristic for multiple different
base currents, and presented the results in a understandable way.
Based on this data you also worked on the extraction of the important
performance parameters (gain, output resistance, and the transition
between the linear and the active region). Unfortunately the
discussion, including a comparison between the measured and
simulated performance, is incomplete.
You successfully set up the circuit and justified your choice of resistors.
You also measured all the currents and voltage levels and presented
your results in an understandable way. Additionally, you compared
your measurement results to your simulation results. However, there is
no discussion and also no calculation of the efficiency.
Very nice measurement, of the transistor output characteristic and
presentation of the results. You also extracted the majority of the
relevant performance parameters and compared them to the data
sheet and your simulations. The discussion is not sufficient.
Very nice measurement, of the transistor output characteristic and
presentation and discussion of the results.
The comparison between the simulated characteristic and the data
sheet is appropriate.
At the same time you have to improve your extraction of all the
relevant performance parameters.
The circuit is working, you measured all the important voltages and
currents, and you explained your choice of resistors. Furthermore you
also compared the results to your simulation. You made some efforts to
calculate the circuit efficiency and to discuss your findings,
Nevertheless this parts can still be improved.
Very nice measurement and discussion, of the transistor output
characteristic and presentation of the results. You also extracted the
majority of the relevant performance parameters, and compared them
to the data sheet and your simulations.
Your circuit works and you included all the required information into
your report (including comparison to your simulation). Additionally you
also have a very good discussion of your results and calculated the
circuit efficiency.
OR:
You successfully set up the circuit. You also measured all the currents
and voltage levels presented your results in an understandable way,
and included some calculation concerning the efficiency of the circuit.
However, there is no in depth discussion and also no comparison
between your measurement results to your simulation results.
OR:
The circuit is working, you measured all the important voltages and
currents, and calculated the circuit efficiency. Furthermore you also
compared the results to your simulation. You made some efforts to
discuss your findings, Nevertheless this parts can still be improved.
You set up a working common emitter amplifier and justified your
choice of resistors and capacitors. You also characterized your circuit,
present your results, and put some effort to extract the important
parameters (upper and lower cut-off frequency, gain) and to compare
the results to your simulation. Nevertheless, your discussion and your
results concerning the bypass capacitor have to be improved.
Your circuit works nicely and you acquired two good Bode plots (with
and without the bypass capacitor). You justified your choice of resistors
and capacitors. You also extracted the important parameters from the
Bode plots and compare them to your simulation results. The only
aspect you have to improve is your discussion.
A very good demonstration and characterisation of a common emitter
amplifier. You acquired two very good Bode plots (with and without the
bypass capacitor) and discussed your results. You also justified your
choice of resistors and capacitors, extracted the important parameters,
discussed them and compare them to your simulation results.
OR:
You set up a working common emitter amplifier. You also characterized
your circuit with and without bypass capacitor), present your results,
and put some effort to extract the important parameters (upper and
lower cut-off frequency, gain) and to compare the results to your
simulation. Nevertheless, your discussion and the way you present your
results has to be improved.
OR:
Your circuit works nicely and you acquired a good Bode plot. You
justified your choice of resistors and capacitors. You also extracted the
important parameters from the Bode plots, compare them to your
simulation results, and included a good discussion. The only part you
have to improve is the bypass capacitor related task.
OR:
A very good demonstration and characterisation of a common emitter
amplifier. You determined the important performance parameters
(with and without bypass capacitor) and discussed your results.
Additionally, you also invested some effort to identify and discuss any
unexpected behaviour. You also justified your choice of resistors and
capacitors, extracted the important parameters, discussed them and
compare them to your simulation results.
You tried to set up an
amplifier circuit,
unfortunately you were not
able to acquire any
meaningful measurement.
You tried to set up an amplifier circuit,
unfortunately you were not able to measure any
amplification.
You were able to set up the circuit and to
demonstrate some amplification. Unfortunately,
there is no in depth characterisation of your
amplifier.
0%
18%
35%
40%
60%
80%
100%
Your report exhibits an appropriate structure. The
way the content is presented is not very
appealing.
Your report exhibits a logical structure and is understandable.
It would be good to improve the way the data is presented and to make
the presentation more consistent
OR:
Your report exhibits is understandable. Also the way the data is
presented is appropriate and the presentation is consistent.
It would be good to improve the structure of the report. Maybe using
the provided template could help.
Your report is written in a very nice way. Also the presentation is
appropriate.
Your report is written and presented in a very nice, understandable and
concise way.
Your "report" just a
collection of numbers. It is
not understandable at all.
Maybe you should think
about using the provided
template the next time.
Report:
Layout,
structure, and
understandability
of the report
5%
Template:
Use of the
provided Latex or
Word template
You have not
used any of
the templates
0%
18%
Self-assessment:
Use of provided
table to asses
own report
Nothing at all
Absolutely unrealistic
10%
You set up the switching circuit and controlled
the LED using a small base current. A better mark
would require: the measurement of all the
currents and voltage levels, and a justification of
your choice of resistors.
OR:
You successfully simulated the LED circuits, and measured the
important voltages and currents. At the same time your calculations to
determine the resistor values are not clear.
100%
No effort at
all.
5%
Self-assessment
You set up a circuit to light up the LED. A better
mark would require: switching operation, the
measurement of all the currents and voltage
levels, and a justification of your choice of
resistors.
You did set up the circuit on the ELVIS board and
showed that the emitter current depends on the
base current and the collector-emitter voltage. At
the same time you should invest more effort in
presenting your results, extracting the important
performance parameters, and discussing the
results. Also comparing the measured results to
the data sheet and your simulation is an
important point.
You successfully simulated the LED circuit. Your calculations to
determine the resistor values are clear. However you did not measure
all the important voltages and currents.
80%
You simulated a meaningful output characteristic, presented the results
in an understandable way and extracted the majority of the relevant
performance parameters (gain, output resistance, and the transition
between the linear and the active region). You missed to include an in
depth of your results and to compare them with the data sheet.
OR:
Very nice simulation, of the transistor output characteristic and
presentation and discussion of the results. The comparison between
the simulated characteristic and the data sheet is appropriate. At the
same time you have to improve your extraction of all the relevant
performance parameters.
You successfully simulate the LED circuit, also your calculations to
determine the resistor values are clear. Additionally, you measured the
important voltages and currents. Unfortunately you did nit calculate
the efficiency based on this simulation.
OR:
You successfully simulated the LED circuits, and extracted the
important voltages and currents. You also used this values for some
calculations concerning the efficiency of the circuit. At the same time
your calculations to determine the resistor values are not clear.
It looks like there is no underlying structure.
Additionally, the way the content is presented is
not very appealing. Maybe you should think
about using the provided template the next
time.
You used a template, but not in a proper way.
Problems are associated to the comments
function, the references, or the example figures
or text
35%
You used one of the templates
40%
60%
5/5
80%
100%
This makes sense
This makes sense and is presented in a very nice and understandable
way