Question: What is the primary purpose of a comparator circuit using an op-amp?

Options:

1. To amplify AC signals
2. To compare two voltages and output a digital signal
3. To filter out noise
4. To provide feedback in a control system

Correct Answer: To compare two voltages and output a digital signal

Solution:

A comparator circuit compares two input voltages and outputs a digital signal indicating which input is higher.