Pole and Throw

In switches, "pole" and "throw" refer to the number of input/output contacts and the number of positions that the switch can make, respectively.

A "pole" refers to the number of separate circuits that a switch can control. A switch with one pole (SP) can control one circuit, while a switch with two poles (DP) can control two separate circuits.

A "throw" refers to the number of positions that a switch can make. A switch with one throw (ST) can only make one connection per pole, while a switch with two throws (DT) can make two different connections per pole.

For example, an SPST switch has one pole and one throw, meaning that it can control one circuit and has only one on/off position. An SPDT switch has one pole and two throws, meaning that it can control one circuit and can switch between two different connections. A DPDT switch has two poles and two throws, meaning that it can control two separate circuits and can switch between two different connections for each circuit.

In summary, the terms "pole" and "throw" describe the number of circuits that a switch can control and the number of connections that it can make per circuit, respectively.

【 Go Back 】 | 【 Print 】