Operational Amplifiers Lab

Operational Amplifiers Lab

Abstract:

This lab will demonstrate the different forms of the operational amplifier. By connecting circuits from previous labs to an operational amplifier, we will be able to see the different operations that a Op-amp can perform. The various formulas will be tested for the accurateness in predicting the output of an op amp.

Data:

Equipment Used:

ELVIS workbench

DMM

protoboard

various resistors

wire

Circuit 1

Calculation: V1 = 15V/20k-ohms * 2k-ohms = 1.500 V

V2 = 15V/20k-ohms * 1k-ohms = .7500 V or 750 mV

Measured: V1 = 1.510 V

V2 = .756 V

Inverter Data

Circuit 2

Circuit 2 is constructed with R1 = 33k-ohms, Rf = 120k-ohms, and R4 = infinite

Free end of R1(Circuit 2) is connected to V1(Circuit 1).

Calculation for the combination of Circuits 1 & 2: -Rf/R1 * V1 = -12k-ohms / 33k-ohms * .75 = -5.45 V

Measured value for combo. of Circuits 1 & 2: V3 = -5.22 V

 with R4 = infinite: V3 = -5.22 V

= 3k-ohms: V3 = -5.21 V

= 500 ohms: V3 = -5.21 V

= 300 ohms: V3 = -5.21 V

= 200 ohms: V3 = -5.21 V

Summer Data

Circuit 3

Constructed Circuit 3 using Rf = 120k-ohms, R2 = 33k-ohms, R2(Inverting Summer) is connected to V2 of Circuit 1. V1 and R1 (Inverting Summer) are removed.

Calculation for the Combination of Circuits 1 & 3: V3 = -120k-ohms / 33 k-ohms * .75 = -2.727 V

Measurements of the combo of Circuits 1 & 3: V3 = -2.671 V

Calculation for the combination of Circuits 1 & 3 (with R1 = 33k-ohms and connected to V1(Circuit 1): V3 = -(120k-ohms / 33k-ohms) * 2 = -8.18 V

Measurement of the combo of Circuits 1 & 3 (with R1 = 33k-ohms and connected to V1(Circuit 1): V3 = -7.68 V