5 - Taking Control with Switches
Switches allow us take control, by interrupting the current flowing around a circuit. There are many different types of
switch and places where they are used.They need to be carefully chosen to suit the user who is operating them and the type of environment they are
used in. Here are a few examples - Can you think where they are used?
S.P.S.T
type Switches

S.P.S.T. stands for "Single Pole Single Throw". These switches
have two connections and are the simplest to use. They either allow current to flow,
or not flow.
The symbol above, shows the switch is normally open. When it is first operated, it is made to close.
Switches can either stay in the position they are put - latching types, or return to their previous position after they have been released - momentary types.
The room light wall switch above, needs to be a "latching" type. This is important as it needs to retain the position it has been put, when the user's finger is removed.