

Practical Op Amp Differentiator Lab
Objectives:
To build, predict, and measure the characteristics of a practical differentiator in various regions of operation.
Figure 1: A Practical Differentiator
1. Assuming steady state AC operation, calculate A_{vmb} , f_{a} , f_{b} ,
f_{c} , and f_{d} for the circuit shown in Figure 1.
2. Construct the circuit shown in Figure 1.
3. Looking at Figure 1 as a differentiator for frequencies below, f_{b} , predict,
observe and simulate on PSpice Vo for the following input waveforms. Express the predicted
value of Vo as Vop sin(2π f t + θ) for waveforms A, B, and C.
A. Vi = 0.5V sin 2π 100t
B. Vi = 0.5V sin 2π 500t
C. Vi = 0.5V sin 2π 1000t
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For waveforms D through F below, sketch two full cycles of the input waveform and the
predicted, measured, and PSpice output waveforms on graph paper.
D. Vi = ± 1V triangle wave at 100Hz
E. Vi = ± 1V triangle wave at 500Hz
F. Vi = ± 1V triangle wave at 1kHz
G. Vi = ± 250mV square wave at 1kHz
4. Looking at Figure 1 as a band pass filter;
A. Use PSpice to find, A_{vmb} , f_{center} , f_{low} ,
f_{high} , and Plot Phase of Vo from 1Hz ≤ f ≤ 1MHz.
B. Measure the circuit in Figure 1 for, A_{vmb} , f_{center} ,
f_{low} , f_{high} , and compare the results to the Bode plot
calculated in step 1.
5. Looking at Figure 1 as an integrator for frequencies above fc for an input
Vi = ± 10mV square wave at 50kHz, predict, measure, and simulate on PSpice
the output waveform. Sketch the results on graph paper for comparison.
Electrical Engineering lab key words: Practical operational amplifier
differentiator, opamp, AC operation, waveforms, bode plot, center
frequency, Pspice, input and output voltage, difference, cycles.
