What is a zero-crossing detector and in what applications is it commonly used?

What is a zero-crossing detector and in what applications is it commonly used?

• A. A device that amplifies high-frequency signals for long-distance transmission.
• B. A circuit that detects when a waveform crosses zero, used for timing, phase detection, or simple synchronous sampling.
• C. A component that filters out DC components from a signal.
• D. A sensor that measures temperature changes.

Answer: (B)