Keyboard Switches

Keyboard Switches

Keyboard switches are components of computer keyboards that interpret key strokes and send a current signal through electrical cables to a processor that interprets it. They are types of membrane switches and are located underneath the hard keys. These switches are composed of a flat, flexible surface and act as a medium between the keys and the underlying circuits as well as provide a sound and tactile response for the typer. They are inexpensive, easy to mass produce and are resistant to dirt and liquids. Keyboard switches are either mechanical or non-mechanical and are composed of four parts-the rubber domes, a membrane, metal contact and foam element. They are used by computer and electronics manufacturers to produce most of the computer keyboards used today.

There are a number of switch technologies that keyboards use. Capacitive switches are non-mechanical because the current is constantly flowing through all parts of the keyboard matrix. They keys are spring-loaded and press down on a metal plate, which touches another plate beneath it to change the current. The processor detects the change and interprets it as a key stroke for that certain spot. The rest of keyboard switch technologies are mechanical.  Dome switches are the most common kind. In this process, the key stroke presses down on a dome beneath the key, which is part of the membrane. It then connects to a pair of conductive lines and causes electric current to flow. Finally, metal contact switches use spring-loaded keys that are connected to a piece of metal. When pressed, the metal connects with two circuits, which are sometimes made with a foam piece for better tactile response.