Question

The circuits mentioned in the following options are realized using ideal opamp. Among these, the circuit(s) performing non-linear operation on the input signal is/are:

• A. Instrumentation amplifier
• B. Schmitt trigger
• C. Logarithmic amplifier
• D. Precision rectifier

Hint:

Linear circuits follow the principle of superposition (scaling and addition of inputs). Non-linear circuits like log amps, rectifiers, and hysteresis-based circuits break this rule.

Answer 1

The Correct Option is B, C, D

Step 1: Understanding linear vs. non-linear operation.
A circuit performs a non-linear operation if the output is not a linear function of the input (e.g., output \( \propto \log({input}) \), rectified input, or exhibits hysteresis).
Step 2: Analyze each option.
(A) Instrumentation amplifier: Performs linear amplification of differential signals. So, it's a linear circuit.
(B) Schmitt trigger: A comparator with hysteresis — output changes states at different input voltages depending on the direction of input. This is a non-linear behavior.
(C) Logarithmic amplifier: Produces output proportional to the logarithm of the input. Clearly non-linear.
(D) Precision rectifier: Rectifies the input signal — allowing only positive (or negative) portions to pass through — a non-linear function.