To condition a switch signal so that the receiving logic registers only a single state change per physical press. Because metal contacts are springy, they literally bounce against each other on a microscopic level, creating a rapid train of high and low voltage spikes before settling. Engineers debounce these signals using hardware RC filters, dedicated logic gates, or software timers that ignore transitions occurring within a few milliseconds of the first edge.
If you don't debounce that tactile button in software, a single press will trigger the interrupt five times.
Related terms
Keybounce
The rapid, unintended multiple electrical contacts made when a mechanical switch is pressed.
Schmitt trigger
A comparator circuit that uses positive feedback to create hysteresis, converting noisy analog signals into clean digital pulses.
Edge-triggered
A digital input that responds only to the transition of a clock signal.