Switch

Created on: 30 July 2012

The schematic symbols for two different types of switches are shown below:

Switch schematic symbols

The switch symbol on the left represents a switch that when switched on, will stay on and when switched off will stay off. This switch is a "single pole single throw" switch.

The switch on the right represents a switch that will only be closed when pushed. It will switch off when released and never latch closed. This is known as a momentary switch.

In schematic diagrams, the reference designator for a switch will typically start with S or SW as shown.

The switches on the left of the photo below are momentary tactile switches. The switch immediately to the right of these switches is a bigger momentary switch with a cap. The switch to the right of this is a push button single pole switch. Next is a toggle switch and finally a key switch.

Various switches used in electronics