La vaca cegahisto.cat

02-09-2019 (3275 )

SPST - SPDT - SPCO - SPTT - DPST - DPDT - DPCO

Electronics specification and abbreviation	Expansion of abbreviation	British mains wiring name	American electrical wiring name	Description
SPST	Single pole, single throw	One-way	Two-way	A simple on-off switch: The two terminals are either connected together or disconnected from each other. An example is a light switch.
SPST-NO Form A^[4]	Single pole, single throw, normally open			A simple on-off switch. The two terminals are normally disconnected (open) and are closed when the switch is activated. An example is a pushbutton switch.
SPST-NC Form B^[4]	Single pole, single throw, normally closed			A simple on-off switch. The two terminals are normally connected together (closed) and are open when the switch is activated. An example is a pushbutton switch.
SPDT Form C^[4]	Single pole, double throw	Two-way	Three-way	A simple break-before-make changeover switch: C (COM, Common) is connected either to L1 or to L2.
SPCO SPTT, c.o.	Single pole changeover or Single pole, centre off or Single Pole, Triple Throw			Similar to SPDT. Some suppliers use SPCO/SPTT for switches with a stable off position in the centre and SPDT for those without.^{[citation needed]}
DPST	Double pole, single throw	Double pole	Double pole	Equivalent to two SPST switches controlled by a single mechanism.
DPDT	Double pole, double throw			Equivalent to two SPDT switches controlled by a single mechanism.
DPCO	Double pole changeover or Double pole, centre off			Schematically equivalent to DPDT. Some suppliers use DPCO for switches with a stable center position and DPDT for those without. A DPDT/DPCO switch with a center position can be "off" in the center, not connected to either L1 or L2, or "on", connected to both L1 and L2 at the same time. The positions of such switches are commonly referenced as "on-off-on" and "on-on-on" respectively.
		Intermediate switch	Four-way switch	DPDT switch internally wired for polarity-reversal applications: only four rather than six wires are brought outside the switch housing.
2P6T	Two pole, six throw			Changeover switch with a COM (Common), which can connect to L1, L2, L3, L4, L5, or L6; with a second switch (2P, two pole) controlled by a single mechanism.

******************************************