Switches are used to make or break a circuit. Here are some common varieties and their names.
Poles correspond to the number of circuits that can be switched.
The diagram shows single and double pole switches.
Single throw is a simple on/off switch.
Double throw is a change-over switch.
NO = Normally open.
NC = Normally closed.
COM = The common connection in a double pole switch.
Puzzle
Using two SPDT switches, draw a diagram to show how stair lights work. It should be possible to turn the light on or off both at the top and bottom of the stairs.
Push Button Switch (Push to make)
