What is the NO SPST normally open relay? The NO Normally-Open SPST (Single Pole Single Throw) relay has an opened circuit state when no current is applied to its coil so basically it disconnects the ...

What is the normally closed SPST relay? The NC Normally-Closed SPST (Single Polse Single Throw) relay has an initial closed circuit state when no current is applied to its internal coil therefore it ...

There are standard designations and symbols that describe how electrical ... For example, a Form A relay provides an SPST switch that closes (makes) when a circuit energizes the relay.