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Lab 2

Lab #2

INVERTING AND NON-INVERTING OPERATIONAL‑AMPLIFIERS

1. OBJECTIVES

The primary objective of this experiment is to familiarize you with the basic properties and applications of the integrated‑circuit operational amplifier (the opamp). The opamp is one of the most versatile electronic building blocks currently available to circuit designers. The emphasis will be primarily on the nearly ideal opamp.

2. COMPONENTS AND INSTRUMENTATION

– MC1458 Op-amp IC

– 100 Ω resistors

– 1 KΩ resistors

– 10 KΩ resistors

– DC power supply, for ±10 VDC

– Waveform Generator

– Oscilloscope with probes

– Computer with Multisim software for computer simulations

– Wire, alligator clips, and a breadboard

3. THE INVERTING AMPLIFIER

lab 2_1

3.1    Assemble the circuit as shown above.  Adjust the supplies to ±10V. Use the multimeter and oscilloscope to measure (R1= 10KΩ, R2= 100Ω, R3= 1KΩ, R4= 10KΩ):

a)  Vin open (or grounded).  Measure B, C, and Vout.

b) Vin connected to +10 V.  Measure B, C, and Vout.

c) Vin connected to ‑ 10 V.  Measure B, C, and Vout.

Tabulation:   VB, VC, Vout, for Vin = 0 V, 10 V, 10 V.

Analysis: Calculate the voltage gains Vout/VB and Vout/Vin.

3.2    Use the circuit as shown above. Connect Vin node to +10 V.  Measure (continue to measure Vout node with your multimeter):

a) Shunt resistor R4 with another resistor of equal value to reduce the gain by a factor of 2; Measure Vout, B.

b) Shunt resistor R3 with another resistor of equal value to raise the gain by a factor of 2; Measure Vout, B.

c) Open the connection of R3 to node B.  Add a resistor of equal value in series with R3 and node B.  Name the junction between the new resistor and R3 node X.

Tabulation: R3, R4, Vout, with Vin, VB, VX.

Analysis: Calculate the input resistance Rin at node B.

 4. THE NON‑INVERTING AMPLIFIER

lab 2_2

4.1.   Assemble the circuit shown above. Adjust the supplies to ±10 V. Use the multimeter and oscilloscope to measure (R1= 1KΩ, R2= 100Ω, R3= 1KΩ, R4= 10KΩ):

a) Vin open (or grounded).  Measure B, C, and Vout.

b) Vin connected to + 10 V.  Measure B, C, and Vout.

c) Vin connected to ‑ 10 V.  Measure B, C, and Vout.

Tabulation: VB, VC, Vout, for Vin = 0 V, 10 V, 10 V.

Analysis: Calculate the voltage gains Vout/VB and Vout/Vin.

4.2.   Use the circuit shown above. Connect Vin node to +10 V.  Measure:

a) Shunt R2 with a resistor of equal value.  Measure B, C, Vout.

b) Shunt R1 with a resistor of equal value.  Measure B, C, Vout.

c) Short‑circuit R2. Measure B, C, Vout.

Tabulation: VB, VC, Vout, for R2, R1, for various combinations of R1, R2.

Analysis: Calculate the gain in each case.

4.3    Use the circuit shown above.  Connect Vin to a 5 V peak amplitude sine wave at 1kHz.  Measure:

a)  With your oscilloscope, measure the peak amplitude of signals at B, C, and Vout.

Tabulation: Vin, VB, VC, Vout.

Analysis: Calculate the voltage gains Vout/VB and Vout/Vin.

Lab report is individual and Analysis part should be on your own words.

The Lab report must include all lab procedures, all the observations from hardware and software simulations, and a detailed analysis.

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