2. What is a battery? A battery consists of two or more cells that are joined together. The potential difference across a battery is the sum of the potential differences across the cells. A 12 V car battery contains six 2 V cells inside its case. Circuit symbol for a battery V

3. How can battery voltage be increased? If two or more cells are connected in series, the total voltage across the battery can be found by adding up the cell voltages. 3 V 4.5 V Using more cells in a battery increases the voltage. So, if 2 cells with a voltage of 1.5 V are connected together, the voltage across the battery is 3 V. When three cells of 1.5 V are connected, what is the voltage across the battery? V 1.5 V V V

5. Circuit symbols

6. Circuit components

7. What is a short circuit? Current will always pass along the path of least resistance. The resistance of the wires in a circuit is low compared to the resistance of components, such as bulbs. The current can only pass through the bulb. These circuits both contain a short circuit, so the bulb will not be lit up. If current can flow along a path without passing through the components this part of the circuit is called a short circuit .

8. Voltage Voltage is a measure of the difference in electrical energy between two parts of a circuit. The bigger the difference in energy, the bigger the voltage. Voltage is measured in volts .