05-02-2013, 03:56 PM
DIFFERENTIATOR
DIFFERENTIATOR.docx (Size: 32.5 KB / Downloads: 22)
AIM:
To design a Differentiator circuit for the given specifications using Op-Amp IC 741.
THEORY:
The differentiator circuit performs the mathematical operation of differentiation; that is, the output waveform is the derivative of the input waveform. The differentiator may be constructed from a basic inverting amplifier if an input resistor R1 is replaced by a capacitor C1. The expression for the output voltage is given as,
Here the negative sign indicates that the output voltage is 180 0 out of phase with the input signal. A resistor Rcomp = Rf is normally connected to the non-inverting input terminal of the op-amp to compensate for the input bias current. A workable differentiator can be designed by implementing the following steps:
1. Select fa equal to the highest frequency of the input signal to be differentiated. Then, assuming a value of C1 < 1 µF, calculate the value of Rf.
2. Choose fb = 20 fa and calculate the values of R1 and Cf so that R1C1 = Rf Cf.
The differentiator is most commonly used in waveshaping circuits to detect high frequency components in an input signal and also as a rate–of–change detector in FM modulators.
PROCEDURE:
1. Connections are given as per the circuit diagram.
2. + Vcc and - Vcc supply is given to the power supply terminal of the Op-Amp IC.
3. By adjusting the amplitude and frequency knobs of the function generator, appropriate input voltage is applied to the inverting input terminal of the Op-Amp.
4. The output voltage is obtained in the CRO and the input and output voltage waveforms are plotted in a graph sheet.
RESULT:
The design of the Differentiator circuit was done and the input and output waveforms were obtained.