Ideal Differentiator using Op-Amp : Derivation, Frequency Response and its Limitations

Contents Introduction Expression of output voltage Frequency Response of ideal Differentiator(Bode plot) Limitations/Drawbacks of ideal Differentiator Ideal Differentiator using Op-Amp It produces mathematical operation of Differentiation w.r.t time. In Op-amp integrator circuit, if we interchange the position of resistor and capacitor then it can be used as a differentiator. The relation between the output and input has been derived in this video. Application of differentiator circuit: The differentiator circuit can be used to identify the rate at which the input signal is changing. So, the differentiator circuit can be used to find the high-frequency component of the input signal and it can be used in the application of edge detection. In early days, when digital computers were not evolved at that time for analog computation these op-amp based differentiator circuits were used. Limitation of simple differentiator circuit: In this simple differentiator circuit, as the input frequency increases, the gain of the differentiator will increase. So, the simple differentiator is very sensitive to the high-frequency noise. Also, in simple differentiator, the input impedance of the circuit is equal to the reactance of the capacitor. So at high frequency, the input impedance will reduce. These problems can be overcome by using the practical differentiator circuit. Limitations/Drawbacks 1.Gain increases with frequency that can make circuit unstable and break into oscillations. 2. It is likely to offset towards the positive or negative saturation levels. 3.This circuit is very sensitive high frequency noise 4. It cannot differentiate low frequency signals. Due to these limitations a integrator with additional components called as practical Differentiator is used.