Knife switch

Type of switch Knife switchOpen single-pole single-throw (SPST) knife switchElectronic symbol 1917 motor switch, with extra contacts Dual-pole, dual-throw knife switch in one of its two closed positions A knife switch is a type of switch used to control the flow of electricity in a circuit. It is composed of a hinge which allows a metal lever, or knife, to be lifted from or inserted into a slot or jaw. The hinge and jaw are both fixed to an insulated base, and the knife has an insulated handle. Current flows through the switch when the knife is pushed into the jaw. Knife switches can take several forms, including single-throw, in which the knife engages with only a single slot, and double-throw, in which the knife hinge is placed between two slots and can engage with either one. Multiple knives may be attached to a single handle and can be used to activate more than one circuit simultaneously; this is a multi-pole switch. Operation Current flows through the switch when the knife is in the jaw. When the switch is opened under load, an arc may cause burns. At higher voltages or currents this arc can be sustained, risking vaporization or explosions. Because the blade and jaw are fully