13 Jul 2026

Op-Amp Differentiator and Integrator

practical pg-ii op-amp differentiator integrator

Aim

To study the waveforms produced by practical op-amp differentiator and integrator circuits.

Apparatus

741 op-amp, dual DC supply, resistors, capacitors, function generator, CRO, breadboard, and connecting wires.

Experimental arrangement

The op-amp circuit receives the function-generator signal at its input and the output waveform is compared with the input on the CRO.

Theory

With negative feedback, an ideal op-amp drives its output so that the two input terminals are at nearly the same potential. When the non-inverting input is grounded, the inverting input is therefore at virtual ground and the input current is set by the external impedance. With a resistor at the input and capacitor in feedback, $V_o=-RC\,dV_i/dt$, so the circuit differentiates the input. With a capacitor at the input and resistor in feedback, $V_o=-(1/RC)\int V_i\,dt$, so the circuit integrates the input.

Observations

Input waveform	Differentiator output	Integrator output
Square	Positive and negative spikes	Triangular waveform
Sine	Cosine-like waveform	Negative cosine-like waveform
Triangular	Square waveform	Parabolic segments

Result

The differentiator produces an output proportional to the rate of change of the input, while the integrator produces an output proportional to the time integral of the input.

Viva Questions

1. Why is the op-amp called inverting here? The signal is applied to the inverting terminal and the non-inverting terminal is grounded.
2. What limits a practical differentiator? High-frequency noise and the finite bandwidth of the op-amp.
3. Why is a capacitor used at the input of an integrator? Its impedance causes the input current to be proportional to the time integral of voltage.