Electrical Switches

In electrical circuit switch is one of the most common controlling device which controls the flow of current to accessories and electrical circuits. The switch provides on and off control to various electrical circuits and systems. Contacts are used to carry current inside switch when switch is in on or closed position. When the switch is opened or in off position the flow of current is stopped.

Electrical switches

There are two main kinds of switches. Normally open and normally closed. Normally open switch don’t provide the current path when it is at rest or in off position. It only provides path to current flow when it is in on or closes position. The switch contact remains opened when it is at rest position until an external force doesn’t actuate the switch from off to on position. In this way the circuit is completed and current flow starts.

The other type normally closed or NC switch allows current flow when they are in rest or at off position. There contacts remains closed when they are at rest position. When an external force actuates such kind of switch, its contact become opened and stops current flow or cut off current path from the certain circuit. This way such kind of switch only pass current when it is in the rest position.

Another classification of the switches are according to its make or functionality. Single pole single throw or SPST is the simplest switch used to control simple circuits. There is a single pole which can pass to a single position only when it is actuated. Such type of switch only controls on and off operation of a single circuit. There is another type of SPST switch which is spring loaded type. Such a switch is known as push button. In this kind of switch the contacts are hold by a spring and closing the contacts when it is momentarily pressed. When press is released, the switch comes back to rest position due to the loaded spring. This type of switch is used to control horn and circuits where momentary position is translated to the computer system.