# Op amp Integrator circuit design

Op amp is known as Operational Amplifier. We can design an Op amp integrator circuit using a resistor and a capacitor. In most of the circuits the Op amp consist of a resistor in its feedback but in integrator we connect a capacitor in the feedback. So, lets discuss how an **Op amp Integrator circuit** works.

- As the name implies this circuit performs the mathemaical operation of integration. Therefore the output voltage is proportional to the integral of the input voltage.

## Circuit Diagram

As you can see, we are using Op amp in inverting mode. The input signal is connected to the inverting input of the Op amp. A capacitor is connected in feedback which is between the output and the input terminal. Non Inverting terminal is connected to the ground.

No we connect a function generator at the input and a oscilloscope. The above simulation is done in Multisim Software.

## Working of Op amp Integrator circuit

- +ve terminal is at ground and therefore by virtual ground concept the -ve terminal will be also grounded.
- The current flowing through R1 will be equal to the current flowing through capacitor.
- Ir=Ic and V+=V-=0
- Let input voltage be Vin and Vo be output voltage.

Ir= Vin/R1

Ic= C1 * [d (-Vo)/dt]

Therefore, Vin/R1= C1 * [d (-Vo)/dt]

**Integrating both sides………….**

∫(Vin/R1)dt = ∫C * [d (-Vo)/dt]dt

**Vo = (-1/R1C1) * ∫Vin dt**

- The output voltage is directly proportional to negative integral of the input voltage and inversely proportional to RC time constant.
- We are providing the square wave input which means the output will be triangular wave.

## Output waveform:

- The above triangular waveform is the output and the below square wave is the input.

Our input parameters of Function generator:

### Check out this video for simulation in Multisim.

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