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 ...
As you can see in the schematic the 12V battery (or use other voltages) is connected with the plus at terminal T1 and minus at terminal T2. The contact 1 and 4 are connected together as 2 and 3 are ...