Simple circuits - CCEAPage 2

Cell polarity

The symbol for a battery is made by joining two, or more, symbols for a cell together.

These are simple cells.

The type you put in a torch or a TV remote control.

When you join two or more cells together you form a battery – it is a battery of cells.

A cell has a positive terminal and a negative terminal.

For cells such as D, AA and AAA, the positive terminal, (+), is the raised end, normally at the top, while the negative terminal, (-), is the flat end, normally at the bottom.

In the circuit diagram of a cell:

• The long line is the positive (+) terminal.
• The short line is the negative (-) terminal.

When cells are joined together to form a battery they are normally joined with the positive terminal of one cell connected to the negative terminal of the next.

The voltage provided by cells connected in series is the sum of the voltages of each cell.

Example

What is the voltage of this battery?

Answer

Example

In the example above, one of the cells has been connected the other way round.

The negative terminal of the middle cell is connected to the negative terminal of the first cell.

This causes the voltage of both cells to cancel out, and so the total voltage is now only 1.5 V