Electricity needs a path to pass from the positive terminal to the negative terminal of an electric cell. A connection that provides a path outside an electric cell, for the electricity to pass from the positive terminal to the negative terminal of the cell, is called an electrical circuit.
For example, a bulb glows only when the positive terminal and the negative terminal of an electric cell are connected to the two terminals of the bulb.
If the wires from the bulb are connected to the same terminal (either positive or negative), then the bulb doesn’t glow.
Sometimes, the bulb may not glow even though the connections are properly made.
This is because the flow of electricity is incomplete as the filament in the bulb is broken. A broken filament bulb is said to be fused.
A device that is used to stop the flow of electricity by breaking the circuit is called a switch. Switches have wide range of applications. Some common types are:
- Toggle switches, which are used in our houses.
- Pushbutton switches, which are used in the starter of a water pump.
- Joystick switches, which are used in the remote control unit of a toy car.