Complete the text with words from the box. There are TWO words you will not need.

When electrons move through a an electric current is created. A current that always flows in one direction is called a current (DC). A battery for example, produces a direct current. A current that flows back and forth is called an current (AC).

Electrons cannot jump freely through the air to a positively atom. They need a to move. When a source of energy, like a , is connected to a light bulb the electrons can move from the battery to the light bulb and back again. We call this an electric circuit.

Sometimes there are many circuits in an electrical that make it work. A TV set or a computer may have millions of parts that are to each other in different ways.

You can stop the current from flowing by putting a into the circuit. You can open the circuit and stop electrons from moving.

A piece of metal or can also be used to produce heat. When an electrical current passes through , such metal it can be slowed down by . This causes and makes the wires hot. That’s why you can toast your bread in a toaster or dry your hair with warm air from a hairdryer.

In some cases wires can become too hot if too many electrons flow through them. Special switches ,called , protect the wiring in many buildings .