Electric Circuits
. An electric circuit is an arrangement of electric current sources and conducting paths through which a current can continuously flow. In a simple circuit consisting of a small light bulb, a battery, and two pieces of wire, the electric current flows from the negative terminal of the battery, through one piece of connecting wire, through the bulb filament (also a type of wire), through the other piece of connecting wire, and back to the positive terminal of the battery. When the electric current flows through the filament, the filament heats up and the bulb lights. A switch can be placed in one of the connecting wires. A flashlight is an example of such a circuit. When the switch is open, the connection is broken, electric current cannot flow through the circuit, and the bulb does not light. When the switch is closed, current flows and the bulb lights. The bulb filament may burn out if too much electric current flows through it. To prevent this from happening, a fuse (circuit breaker