Question: Which of the following describes a zero-crossing detector?

Options:

1. A device that measures amplitude
2. A device that detects frequency
3. A device that detects when a signal crosses zero voltage
4. A device that amplifies signals

Correct Answer: A device that detects when a signal crosses zero voltage

Solution:

A zero-crossing detector identifies points where the signal crosses the zero voltage level, which is useful for timing and synchronization.