Double Pole Single Throw DPST Relay
The Double Pole Single Throw DPST relay is the equivalent of 2 SPST switches (NO Normally Open and NC Normaly Closed) and can be used to switch 2 different loads.
We have 2 scenarios depending on the type of relay
- without voltage on coil:
- with a NO the loads will be OFF because the current cannot flow
- with a NC the loads will be ON because the current can flow
- with voltage on coil:
- with a NO the loads will be ON because the current can flow
- with a NC the loads will be OFF because the current cannot flow
Normally Open DPST relay connects 2 loads when voltage is applied
As you can see in the schematics above if we use a NO DPST relay the contacts will be closed only if voltage is applied to the coil.
Normally Closed DPST relay disconnects 2 loads when voltage is applied
In the schematics above if we use a NC DPST relay the contacts will be closed without voltage being applied to the coil and opened when we apply voltage to it.
Related product: Electromechanical Relay
