Electrical Energy & Voltage

Learning Objectives: To describe how energy can be stored e.g.

electrical cells. To describe how energy is transferred e.g.

simple circuits.

Starter: What does a battery do? Explain with reasons.

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

What is a battery?

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

How can battery voltage be increased?

Videos

The power of batteries in a circuit. Current and energy in a circuit.

Circuit symbols

Circuit components

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.

What is a short circuit?

VoltageVoltage 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.

Voltage

The symbol for volts is V. For example, 230V is a bigger voltage than 12V. Voltage is measured using a voltmeter. Some types of voltmeter have a pointer on a dial, but most have a digital readout. To measure the voltage across a component in a circuit, you must connect the voltmeter in parallel with it.

Electricity

Electricity summary

Electrical Energy & Voltage

Learning Objectives:

To describe how energy can be stored e.g. electrical cells.

To describe how energy is transferred e.g. simple circuits.