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EECE 206
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Lab 4b: LM741 Operational Amplifier
Laboratory Goals
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Design and construct a non-inverting amplifier using the op-amp
Measure and record input and output waveforms of the op-amp
Compare actual and theoretical values
Pre-lab reading
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Student Reference Manual for Electronic Instrumentation Laboratories by Stanley Wolf
and Richard Smith, Copyright 1990.
National Semiconductor website (www.national.com). Search for the LM348 datasheet
Equipment needed
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Lab notebook, pen
Systron-Donner Triple DC Power Supply
Tektronix 2252 Digital Oscilloscope
Tektronix FG 501A Function Generator
Tektronix DM 501 Digital Multimeter
2 oscilloscope probes (attached to the oscilloscope)
1 test lead, BNC/EZ Hook
3 test leads, red, banana/EZ Hook
2 test leads, black, banana/EZ Hook
Parts needed
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Circuit breadboard
Lab parts kit
IC, Quad 741 Operational Amplifier, LM 348N (in lab parts kit)
Resistors (2), 1k Ohm
Resistor (to be determined by the circuit gain)
Jumper wires (found in the parts kit)
Lab safety concerns
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Make sure all circuit connections are correct, and no shorted wires exist.
Adjust the power supply to the proper voltages before connecting it to the circuit
Adjust signal generator to the proper level before connecting it to the circuit
EECE 206
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Lab 4b: LM741 Operational Amplifier
1. Pre-Lab Amplifier Designs
 Refer to the LM 348 Datasheet on the EECE website (or http.www.national.com
website) for the 14-pin diagram before wiring the circuit. Each of the pins you
will use are labeled on the schematic below.
 Design the inverting amplifier (shown below) using +1.5 times your lab station
number as the gain (e.g., if your station number is 6, design the circuit to have a
gain of 9)
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Create a table in your lab notebook similar to the one below for the amplifier (an
example column is shown. (The test points are 100Hz, 300Hz, 1kHz, 3kHz,
10kHz, 30kHz, 100kHz, 300kHz, 1MHz input frequencies.
Vin
Vout
Frequency (Hz)
100
1k
Amplitude (Vpp)
Amplitude (Vpp)
Phase (vs. Vin)
Gain
1.16
3.48
-176
3.00
2. Circuit Construction and Signal Measurement
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Build the circuit as shown above (For resistor R2, use the closest resistor value
that you can find in the resistor cabinet)
EECE 206
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Lab 4b: LM741 Operational Amplifier
Turn on the Systron-Donner power supply
Turn the VADJ knob for the B power supply so that its voltmeter reads
approximately +15 VDC
Turn the VADJ knob for C power supply so that its voltmeter reads
approximately –15 VDC
Turn off the power supply
Connect a red banana/EZ Hook test lead between the B power supply output (the
green connector) and the circuit +15 V connection
Connect another red banana/EZ Hook test lead between the C power supply
output (the yellow connector) and the circuit -15 V connection
Connect a black banana/EZ Hook test lead between the COM power supply
ground (the black connector) and the circuit ground connection
Turn on TM 504 module
Locate the DM 501A Digital Multimeter
Press the white DC button in the VOLTS section of the Multimeter for voltage
measurements
Press the white 20V button which selects the voltage range for the multimeter
Connect a pair of red and black banana/EZ Hook test leads to the multimeter
VOLTS and LOW connections respectively
Clip the red and black EZ Hook ends of these test leads to the circuit +15 V and
ground connections respectively
Turn on the power supply
Adjust the VADJ, and FINE knobs for the B power supply until the multimeter
reads approximately +15 V
Unclip the multimeter’s red EZ Hook from the circuit +15 V, and clip it to the –
15 V circuit connection
Adjust the VADJ, and FINE knobs for the C power supply until the multimeter
reads approximately –15 V
Unclip the multimeter’s red and black test leads from the circuit and set them
aside
Turn on the oscilloscope
Briefly clip the CH1 probe to the CALIBRATOR test point and observe the
displayed square wave (always make sure the probes are working correctly!)
Briefly test the CH2 probe using the same test point
Locate the FG 501A Function Generator
Press the white ~ (sine wave) output button to select a sine wave output
Press the white FREE RUN button to select a continuous sine wave output
Press the white –20dB button to decrease the voltage output of the generator
Turn the gray MULTIPLIER knob on the generator to the 10 (i.e., 10 Hz) setting
Turn the AMPL knob fully counter-clockwise (i.e. output voltage to minimum)
Connect the BNC/EZ Hook test lead to the function generator OUTPUT
EECE 206
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Lab 4b: LM741 Operational Amplifier
Connect the red and black EZ Hook ends of this test lead to the circuit input and
ground connections respectively
Connect the CH1 oscilloscope probe and ground clip to the same circuit input and
ground connections respectively
Adjust the function generator AMPL knob until the amplitude of the CH1
oscilloscope signal is approximately 1Vpp
Turn the FREQUENCY dial on the generator until the frequency of the CH1
oscilloscope signal is approximately 100Hz
Record the input frequency and voltage on your table for circuit 1
Connect the CH2 oscilloscope probe and ground clip to the circuit output and
ground connections respectively
Measure and record the circuit output and phase on your table for circuit 1
Repeat the frequency, voltage, and phase measurements for the required input
frequencies
After all the measurements have been recorded, turn off the power supply
Unclip all of the test leads from the circuit (except for the +/- power supply
connections)
Before leaving the lab, take a few minutes to make sure all equipment and test leads are
returned to your cabinet, and that you have cleaned up your work space.
3. Analysis
Write a summary report combining both parts 4a and 4b. Be sure to also include the
following topics:
What is the gain of each amplifier at the tested frequencies? (Gain = Av = Vout / Vin).
Create an Excel (or any software you would like) graph of the gain vs. input frequency
for each amplifier. (Make the gain (y-axis) a linear scale, and the frequency (x-axis) a
log scale from 10Hz to 10MHz)
What applications can you think of for these circuits?
Compare theoretical vs. measured values. Explain how/where you got the theoretical
results. Are there differences? If so, why? Analyze the differences.
Explain any difficulties you had with this lab. (Please include suggestions to improve the
lab, if you have them).