Switches
|
| Component |
Circuit Symbol |
Function of Component |
Push
Switch
(push-to-make) |
 |
A push switch allows current to flow only when the button is
pressed. This is the switch used to operate a doorbell. |
|
Push-to-Break Switch |
 |
This type of push switch is normally closed (on), it is open (off)
only when the button is pressed. |
On-Off
Switch
(SPST) |
 |
SPST = Single Pole, Single Throw.
An on-off switch allows current to flow only when it is in the closed
(on) position. |
2-way
Switch
(SPDT) |
 |
SPDT = Single Pole, Double Throw.
A 2-way changeover switch directs the flow of current to one of two
routes according to its position. Some SPDT switches have a central
off position and are described as 'on-off-on'. |
Dual
On-Off Switch
(DPST) |
 |
DPST = Double Pole, Single Throw.
A dual on-off switch which is often used to switch mains electricity
because it can isolate both the live and neutral connections. |
Reversing
Switch
(DPDT) |
 |
DPDT = Double Pole, Double Throw.
This switch can be wired up as a reversing switch for a motor. Some
DPDT switches have a central off position. |
|
Relay |
 |
An electrically operated switch, for example a 9V battery circuit
connected to the coil can switch a 230V AC mains circuit.
NO = Normally Open, COM = Common, NC = Normally Closed.
|
