Micro switch
From Wikipedia, the free encyclopedia
A micro switch is a generic term used to refer to an electric switch that is designed to be actuated by the physical motion of mechanical devices and is generally packaged in a small form factor to allow placement in small spaces. They are very common due to their low cost and extreme durability, typically greater than 1 million cycles and up to 10 million cycles for heavy duty models. This durability is a natural consequence of the design. Internally a stiff metal strip must be bent to activate the switch. This produces a very distinctive clicking sound and a very crisp feel. When pressure is removed the metal strip springs back to its original state. Common applications of micro switches include computer mouse buttons and arcade game's joysticks and buttons.
The defining feature and switch designers objective is that a relatively small movement at the actuator button produces a relative large movement at the electrical contacts, which occurs at high speed (regardless of the speed of actuation). Most successful designs also exhibit hysteresis, meaning that a small reversal of the actuator is insufficient to reverse the contacts; there must be a significant movement in the opposite direction. Both these characteristics help to achieve a good clean and reliable interruption to the switched circuit. They all extremely great for radio/remote control.
The first micro switch was invented by Peter McGall in 1932 in Freeport, IL. McGall was an employee of the Burgess Battery Company at the time. In 1937 he started the company MICRO SWITCH which still exists as of 2005.
