Toggle switches are one the most basic types of switch. The switch moves contacts that either provide a path for current to flow through or moves those contacts in such a way that the path is cut. The toggle switches most people will be familiar with are light switches. You can learn more in our complete guide to toggle switches.
Momentary Toggle Switch
Requires force to move the toggle into the on position, the force must remain applied for the switch to work. As soon as the force is removed the toggle will spring back to its original state.
Momentary toggle switches ALWAYS have brackets around the momentary position.
(On)-Off-(On)
Momentary (On) in both left and right-hand positions.
(On)-Off
Momentary (On) in left-hand position only.
Latching Toggle Switch
When force is applied to the switch actuator the switch will change state and 'latch' into place. The switch will remain latched until the force is again applied to the actuator, the switch will then un-latch and return to its normal state.
Latching switches DO NOT have brackets around any of their switch positions.
On-Off-On
Latching in On in both left and right-hand positions
On-Off
Latching On in the left-hand position only
Contact Configuration of a Toggle Switch
A SPST switch is a simple toggle switch. They allow on and off operation for a single circuit. Most light switches are SPST switches.
A SPDT switch is used to change where a voltage is directed. The double throw means that the switch can be used to energize two different circuits - one at a time - from a single source of energy.
A DPST switch allows an operation that is similar to having two SPST switches hooked together in one device. The switch can turn two circuits on and off. These are useful when more than one device needs to be controlled with the same switch.
A DPDT switch allows two different circuits to be served by the same pole. They are used in applications where a circuit may need to have changing voltages applied to connected devices.