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

Opamp as an integrator
Opamp as an integrator- 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.

Op amp integrator circuit
Op amp integrator circuit

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:

Output- Op amp integrator circuit
Output- Op amp integrator circuit
  • The above triangular waveform is the output and the below square wave is the input.

Our input parameters of Function generator:

Inpur parameters
Input parameters

Check out this video for simulation in Multisim.









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