OFFSET NULL-
INVERTING INPUT-
NON-INVERTING
INPUT
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LM741 Pinout Diagram
W4 -Lab 4 Comparator-OL 2023-06.docx
8-NC
OUTPUT
OFFSET NULL
Objectives:
After completing this experiment, you should be able to,
1. Observe the behavior of Op-Amp as a comparator.
2. Build and test op-amp as a zero-level detector/sine-to-square
wave convertor.
Components needed:
Instruments used:
Submission Requirements:
Submit the Multisim.ms 14 file along with your Experiment 4 lab
document.
1. Potentiometers: 1k, 10k
Multimeter (DMM)
2. Op-Amp: (1) LM741CN
Oscilloscope
Dashboard
4: Comparators
5G
Procedure:
1. The LM741C is 8-pin op-amp. The pinout is shown in
Figure 1. Observe there is a notch and a dot on the IC. The
left side pin to the notch/dot is pin 1.
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Figure 1: LM741 Pinout and Breadboard
placing
1. Digital
2. Construct the following circuit shown in Figure 2 in
MultiSim. Use voltage probes at both inputs and the
output to measure the results for the first setting_in
Table 1.
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To Do
2.
Notifications
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W4 -Lab 4 Comparator-OL 2023-06.docx
Table 1: Calculated and measured values
6. Repeat step 3 through 5 for various voltage values at pin 3
and pin 2 as shown in rows 2,3, and 4 in Table 1.
7. Modify the above circuit as shown in Figure 3. Note that pin
3 is now connected to the function generator
FGEN
VCC 15V
Dashboard
1kQ2
Pot
-15.0V
VEE
VCC
15V
-15.0V
VEE
waveforms
8. Set function generator to 10V, 1 kHz sinewave.
PP'
Figure 3: Op-Amp Comparator sine-to-square
wave convertor
Place Your Schematic Here
U1
9. Connect CH_A of the oscilloscope to the input signal(pin 3)
and CH B to the
output (pin 6) of the comparator.
10. Tune the 1k2 potentiometer by observing the rectangular
wave until you get a perfect square wave (with the
amount of positive time being approximately the same as
the amount of the negative time) as shown in Figure 4.
(-50% duty cycle)
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LM741CN
5G 5
Figure 4: Comparator input and output
11. Measure the DC voltage at pin 2 using a voltage probe.
The measured voltage
is
12
Place Your Scope Display Here
To Do
Notifications
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2. Construct the following circuit shown in Figure 2 in
MultiSim. Use voltage probes at both inputs and the
output to measure the results for the first setting in
Table 1.
10kΩ
Pot
Pin 3 Pin 2 Pin 6
V+
V- VOUT
IV-IV
VCC
15V
5V -6V
-2V 7V
-5V 10V
-15:0V
VEE
Dashboard
VCC 15V
1kQ
Pot
-15.0V
VEE
Figure 2: Op-Amp Comparator
Place Your Schematic Here with voltage measurement probes
Display results for row 1 of Table 1
I VCC
15V
3. Measure the voltage at pin 3 using a voltage probe and
adjust the 10k potentiometer according to the voltage
listed in Table 1.
-15.0V
VEE
4. Measure the voltage at pin 2 using a voltage probe and
adjust the 1k2 potentiometer according to the voltage listed
in the first row of Table 1.
5. Measure the output voltage at pin 6 using a voltage probe
and record the result in
Table 1.
FGEN
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U1
Table 1: Calculated and measured values
LM741CN
6. Repeat step 3 through 5 for various voltage values at pin 3
and pin 2 as shown in rows 2,3, and 4 in Table 1.
5G 5
7. Modify the above circuit as shown in Figure 3. Note that pin
3 is now connected to the function generator
VCC
15V
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To Do
Notifications
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Oscilloscope-XSC1
Dashboard
Place Your Scope Display Here
14. Now modify the circuit by reversing the inputs such
that, the input signal connects
to pin 2 and the potentiometer wiper connects to pin 3.
Adjust the 1k pot to obtain
a 50% duty cycle output.
VCC 15V
1kQ
Pot
its
-15.0V
VEE
FGEN
*********
VCC
15V
-15:0V
VEE
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Figure 5: Inverted Comparator
Place Your Schematic Here
15. The observed phase shift between the input and output signal
is
degrees.
Place Your Scope Display Here
***
U1
LM741CN
.5G 5
12
To Do
*End of the experiment
Notifications
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W4 -Lab 4 Comparator-OL 2023-06.docx
11. Measure the DC voltage at pin 2 using a voltage probe.
The measured voltage
is
12. While measuring the DC voltage at pin 2, tune the 1kQ
potentiometer so that the DC voltage value begins to go
more negative.
What effect does it have on the comparator output?
Hint: Comment on the output duty cycle and the trigger
level.
Dashboard
Sample scope display below.
Write your observations below.
Oscilloscope-XSC1
Place Your Scope Display Here
Oscilloscope-XSC1
13. While measuring the DC voltage at pin 2, tune the 1k2
potentiometer so that the DC voltage value begins to go
more positive.
What effect does it have on the comparator output?
Hint: Comment on the output duty cycle and the trigger
level.
Sample scope display below.
Write your observations below.
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5G
Place Your Scope Display Here
X
12
To Do
Notifications
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