Laboratory # 8: Inverting Amplifier
ECE 206L
Laboratory Goals
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Familiarize students with Integrated Circuit (IC) construction on a breadboard
Introduce the LM 348N -amp and its applications
Design and construct an inverting amplifier using the op-amp
Measure and record input and output waveforms
Compare measured and theoretical values
Pre-lab reading
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Course Textbook
LM348 datasheet at the website (http://ecelabs.pbwiki.com/ECE-206)
Equipment needed
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Lab notebook, pen
Agilent E3631A Triple DC Power Supply
Agilent 54621A Digital Oscilloscope Check model #
3 cables - BNC to EZ Hook
Figure 1 Photographs of BNC -EZ Hook Cable (left), Banana -EZ Hook wire (right).
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Agilent 33120A Function Generator/Arbitrary Waveform Generator Check
model #
2 test leads, red, banana/EZ Hook (See Fig. 1 )
1 test lead, black, banana/EZ Hook (See Fig. 1)
Parts needed
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Circuit breadboard
Lab parts kit
IC, Quad Operational Amplifier, LM 348N (in the lab parts kit)
Resistors (2), 1k Ohm, ¼ Watt (Brown, Black, Red)
Resistor, ¼ Watt: (to be determined)
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
Pre-Lab Calculations: Inverting Amplifier Design
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Design an inverting amplifier that has a gain of -6.
Let Vin = 1 V and R1 = 1 kΩ. What are the values of R2 and Vout?
Figure 2 Circuit diagram of an inverting amplifier.
Laboratory Procedure
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Refer to the LM 348 datasheet on the ECE website for the 14-pin diagram before
wiring the circuit. Each of the pins you will use are labeled on the schematic
below
Figure 3 Pin diagram for the inverting amplifier.
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Build the circuit as shown above (For resistor R2, use the closest available resistor
value (found in the cabinet) to your calculated R2)
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Set the Agilent power supply:
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Press the Output On/Off button to enable the power supply output
Press the +25V button to select the +/- 25V power supply
Adjust the power supply output to +15VDC
Press and hold the Track button (this allows the negative supply to
automatically track the positive supply voltage setting)
o Press the Output On/Off button to disable the power supply output
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Connect a red banana/EZ Hook test lead between the + output (+/-25V terminals)
and the circuit +15 V connection
Connect a another red banana/EZ Hook test lead between the - output (+/-25V
terminals) and the circuit -15 V connection
Connect a black banana/EZ Hook test lead between the COM power supply
ground and the circuit ground connection
Press the Output On/Off button to enable the power supply output
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Set the Agilent oscilloscope:
o Press the Default Setup softkey to set the oscilloscope to the default state
o Briefly test the CH1 and CH2 BNC-EZ Hook cables using the Probe
Comp test point. Observe and note waveform.
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Set the Agilent function generator:
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Select Utility → Output Setup → High Z → Done
Sine waveform
Amplitude = 1Vpp
Frequency = 100Hz
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Connect the BNC-EZ Hook test lead to the function generator OUTPUT
Connect the red and black ends of the EZ Hook test lead to the circuit input and
ground connections respectively
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Connect CH1 of the oscilloscope to circuit input (follow Fig. 3)
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Connect the CH2 of the oscilloscope to circuit output (follow Fig. 3)
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Measure phase shift between the input and output signals:
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Y/T Phase Shift Measurement on the DSO 1022 scope
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Select “Measure”
Go to page 2 of the menu
Select Delay/Phase Setup
Select CH2 for Phase A
Select CH1 for Phase B
Return to page 1
Select Time
Use the “Push to Select” knob to scroll down to “Phas A → B”
Record the reading.
Repeat the voltage and phase shift measurements for the following frequencies:
100 Hz, 300 Hz, 1 kHz, 3 kHz, 10 kHz, 30 kHz, 100 kHz, 300 kHz, 1 MHz
Table 1 Measured results.
Vin
Vout
Frequency Amplitude Amplitude Phase Shift between input and
[Hz]
Vpp [V]
Vpp [V]
output signals
100
300
1k
3k
10 k
30 k
100 k
300 k
1M
Gain
(Vout/Vin)
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After all the measurements have been recorded, disable the power supply output
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Unclip all of the test leads from the circuit, and turn off the equipment
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See Rubric for Lab # 8 (To be posted by Midnight April 6th, 2010)