Op-Amp Integrator Circuit Experiment

Introduction to Op-Amp Integrators

The integrator circuit, built using an operational amplifier, is one of the fundamental analog circuits. This circuit produces an output that is the time integral of the input signal. Integrators are useful in waveform generation, analog computation, and signal processing.

Experiment Objective

Construct an op-amp integrator circuit and observe the output waveform when a square wave input is applied. Verify the integrator behavior by comparing the input and output waveforms on an oscilloscope.

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Required Components for the Op-Amp Integrator Circuit

Operational Amplifier IC (e.g., LM741 or TL081)
Resistor (10 kΩ)
Capacitor (1 μF)
Function Generator (to produce square wave input)
Oscilloscope (to view waveforms)
Breadboard and connecting wires

Circuit Diagram and Formula

The circuit consists of an op-amp configured with a resistor (R) connected between the input and inverting terminal, and a capacitor (C) between the inverting terminal and output. The non-inverting terminal is grounded. The output voltage (V_out) of an ideal integrator is given by:

V_out = - (1/RC) ∫ V_in dt

Procedure to Build the Op-Amp Integrator

Step 1: Assemble the Circuit

Place the op-amp IC on the breadboard and connect the power supply to it (typically +12V to V_CC and -12V to V_EE).
Connect a resistor (10 kΩ) between the function generator output and the inverting input of the op-amp (pin 2 for LM741).
Connect a capacitor (1 μF) between the inverting input and the output of the op-amp.
Ground the non-inverting input (pin 3 for LM741).

Step 2: Apply the Square Wave Input Signal

Set the function generator to produce a square wave signal at 1 kHz with a peak-to-peak voltage of 2V.
Connect the square wave output to the input of the integrator circuit.

Step 3: Observe the Output Waveform

Connect the oscilloscope probes to the input and output of the op-amp integrator circuit.
Observe and compare the input (square wave) and output (triangular wave) on the oscilloscope screen.

Observations

Record the input and output waveforms displayed on the oscilloscope. The input should be a square wave, while the output waveform should approximate a triangular wave, demonstrating the integration of the input signal.

Analysis of Results

The op-amp integrator circuit integrates the input square wave, producing a triangular waveform as output. The slope of the triangular waveform is determined by the RC time constant, and the output amplitude is inversely proportional to the RC values. By changing the resistor or capacitor value, the integrator’s response can be adjusted.

Conclusion of the Op-Amp Integrator Experiment

This experiment demonstrates the integration function of an op-amp integrator circuit. The circuit successfully converts a square wave input into a triangular waveform, verifying the mathematical integration behavior of the circuit.