Y8 Electricity 01 electrical energy & voltage
Transcript of Y8 Electricity 01 electrical energy & voltage
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.