Single Pole Single Throw (SPST) Switch

What is a Single Pole Single Throw (SPST) Switch?

A Single Pole Single Throw (SPST) switch is a switch that only has a single input and can connect only to one output. This means it only has one input terminal and only one output terminal.

A Single Pole Single Throw switch serves in circuits as on-off switches. When the switch is closed, the circuit is on. When the switch is open, the circuit is off.

SPST switches are, thus, very simple in nature.

Single Pole Single Throw (SPST) Switch Circuit

Below is an example of a circuit which utilizes a single pole single throw switch.

When the SPST is closed, the circuit is open and light from the lamp switches on. When the SPST is then opened, the light from the lamp goes out and the circuit is off.

This shows the basic nature and function of a SPST.

Related Resources

Single Pole Double Throw (SPDT) Switch

Double Pole Single Throw (DPST) Switch

Double Pole Double Throw (DPDT) Switch