自动控制上的SPST，SPDT，DPST和DPDT触点配置图解

SPST(Single Pole Single Throw)：单刀单掷开关。

SPDT(Single Pole Double Throw)：单刀双掷开关。

DPDT(Double Pole Double Throw)：双刀双掷开关。

SPST-NO单刀单掷-常开线圈通电时闭合

SPST-NC单刀单掷-常闭线圈通电时断开

SP and DP refer to single pole and double pole, ST and DT refer to single throw and double throw.

Pole refers to the number of circuits controlled by the switch: SP switches control only one electrical circuit. DP switches control two independent circuits (and act like two identical switches that are mechanically linked). Do not confuse ‘pole’ with ‘terminal’. The DPST switch, for example, has four terminals, but it is a DP, not a 4P switch.

Throw refers to the extreme position of the actuator: ST switches close a circuit at only one position. The other position of the handle is Off. DT switches close a circuit in the Up position, as well as the Down position (On-On). A DT switch can also have a center position (frequently On-Off-On).

Single pole/throw and double pole/throw switches are by far the most common switches, but triple and quadruple configurations are also available. They are commonly denoted 3PST, 3PDT, 4PDT, etc.

SP 和 DP 指单刀和双刀，ST 和 DT 指单掷和双掷。

极数是指开关控制的电路数量：SP开关只控制一个电路。 DP 开关控制两个独立的电路（并且就像两个机械连接的相同开关）。不要将“极”与“终端”混淆。例如，DPST 开关有四个端子，但它是 DP，而不是 4P 开关。

投掷是指执行器的极限位置：ST 开关仅在一个位置闭合电路。手柄的另一个位置是关闭。 DT 开关在 Up 位置和 Down 位置 (On-On) 闭合电路。 DT 开关也可以有一个中心位置（通常是 On-Off-On）。

迄今为止，单刀/掷和双刀/掷开关是最常见的开关，但也提供三重和四重配置。它们通常表示为 3PST、3PDT、4PDT 等。