- Differentiator Op Amp Definition: A differentiator op amp circuit produces an output signal proportional to the input signal’s rate of change.
- Basic Circuit Diagram: It involves an inverting amplifier with a capacitor at the input terminal.
- Ideal Op Amp Conditions: In an ideal op amp, the voltage at both terminals is the same, and no current flows into these terminals.
- Kirchhoff Current Law Application: Applying Kirchhoff’s Current Law at the circuit’s node helps determine the output voltage.
- Output Voltage Relationship: The output voltage is the derivative of the input voltage, showing proportional change.
An op amp differentiator is an inverting amplifier with a capacitor at the input terminal. The basic circuit diagram illustrates this setup.
We will first assume that the op amp used here is an ideal op amp. We know that the voltage at both the inverting and non-inverting terminals of an ideal op amp is the same. Since the electric potential at the non-inverting terminal is zero (it is grounded), the electric potential of the inverting terminal is also zero, as the op amp is ideal; this is called virtual ground. It is also known that the current entering the inverting and non-inverting terminals of an ideal op amp is zero.
Given these ideal op amp conditions, applying Kirchhoff Current Law at node 1 of the op amp differentiator circuit, we find:
This equation indicates that the output voltage is the derivative of the input voltage.
