What happens when the level of a comparator’s input signal crosses the threshold voltage?

A comparator is a specialized electronic circuit that compares two input voltages—usually a signal voltage and a fixed reference (threshold) voltage. Its output is designed to saturate completely to either the positive or negative supply rail. When the input signal crosses the predefined threshold voltage, the comparator detects the change in relative voltage levels and immediately changes its output state (e.g., from low to high, or high to low). Distractors suggesting the IC becomes unstable or outputs the reference level fail to understand the binary, switch-like nature of a comparator's output.