UNIT OVERVIEW

Think about switching on a torch or using a TV remote. These devices need electricity, but they are not plugged into the wall. They use cells (often called batteries) to work.

In this unit, you will learn where the electrical energy in a cell comes from. You will also learn how we control electricity using something called resistance.

By the end of this unit, you will be able to:

• Explain how an electric cell produces electrical energy
• Draw and recognise circuit symbols for a cell and a battery
• Calculate the voltage when cells are connected in series or parallel
• Define resistance and explain how it affects current
• Identify the factors that change resistance in a conductor
• Use Ohm's Law to solve simple problems

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