Machine Switches

A switch is an electrical componant  that can disconnect or connect the conducting path in an electrical  circuit , interrupting the electrical  circuit  or diverting it from one conductor to another. The most common type of switch is an electromechanical device consisting of one or more sets of movable electrical  contacts  connected to external circuits. When a pair of contacts is touching current can pass between them, while when the contacts are separated no current can flow.

Switches are made in many different configurations; they may have multiple sets of contacts controlled by the same knob or actuator, and the contacts may operate simultaneously, sequentially, or alternately. A switch may be operated manually, for example, a llight switch  or a keyboard button, or may function as a sensing element  to sense the position of a machine part, liquid level, pressure, or temperature, such as a thermostate. Many specialized forms exist, such as the toggle switch , rotary switch, mercury switch, push button switch, reserving  switch , relay ,  and circuit breaker . A common use is control of lighting, where multiple switchecht may be wired into one circuit to allow convenient control of light fixtures. Switches in high-powered circuits must have special construction to prevent destructive arcing when they are opened.