Design & Technology Resources
Batteries and cells come in all different shapes and sizes and there are many different types.
The pictures to the right show three different types of cells. We usually call them batteries but they are actually cells. A battery is when more than one cell is connected together.
Although they all look different, each of the cells shown to the right all produce a voltage of 1.5V.
The larger cells, such a D and C cells, can supply more current and are best suited for high power products such as torches and remote control cars.
The smaller cells, such as AA and AAA cells, are used for less demanding products such as remote controls, mp3 players and clock etc.
The advantage of the D and C cells is that they have a high capacity and can supply more current and last longer. They are however heavy and large.
The advantage of the AA and AAA cells is that they are much lighter and smaller. They have a lower capacity however and cannot supply high currents for very long.
A battery is a collection of cells arranged to produce higher voltages or currents. The diagram to the right shows how six 1.5V AA cells can be connected in series to create a voltage of 9V.
Inside a 9V battery, each layer is a 1.5V cell
A 9V (PP3) battery is a battery because inside it has a number of cells all piled up on top of each other.
Although a 9V battery supplies more voltage than a single AA cell it cannot supply high currents. A battery of six AA cells (as shown above) would produces 9V but has a much greater capacity than a single PP3. The advantage of a PP3 battery is that it is small and light and is useful in low power circuits. For this reason they are used in smoke detectors.
Rechargeable Cells and Batteries
Coin cells are about the same size as a 10 pence coin. They supply a voltage of 3V and are used in situations where a very small power source is required.
They are found in hearing aids and car lock remote controls.
Circuit diagram of the circuit above