Comparators are electronic devices used to compare two voltage levels and output a signal indicating which one is higher. They are commonly used in circuits to detect changes, such as triggering an event or switching between states. Comparators are essential in applications like zero-crossing detectors, waveform generation, and signal processing, providing fast and accurate responses. With a simple design, comparators help in converting analog signals into digital outputs, making them crucial components in many embedded systems and control applications.