Clean Switch

There is nothing worse in a circuit than a noisy switch. Even the slightest bounce will cause a double “on” and lead to double digits on your calculator display, or extra pulses into a million dollar computer system. So what to do? This circuit shows the basic idea used throughout the computer industry. The CD 4001 NOR gates are hooked up in flip-flop fashion so that once they flip, they stay that way. Double bounces still lead to a single, solid “on” pulse at the output.