Q. Describe an integrator circuit ?

A circuit in which output voltage is directly proportional to the integral of the input is known as an integrating circuit. An integrating circuit is a simple RC series circuit with output taken across the Capacitor C.

In order that circuit renders good integration, the following conditions should be full-filled.

1. The time constant RC of the circuit should be very large compared to the time period of the input wave.

2. The value of R should be 10 or more times larger than Xc.

Let ei be the input alternating voltage and let i be the resulting alternating current. Since R is very large compared to capacitive reactance Xc of the capacitor, it is reasonable to assume that the voltage across R(i.e. eR) is equal to the input voltage.i.e.

Thus the output is proportional to the time integral of the input.