Physics-Electricity

Electrical circuits are connected in series or in parallel. Circuit components are shown as symbols. Name the 2 types current.

Alternating current (AC) and direct current (DC).

Name the two types of forces between charged objects

Attraction and repulsion

Neutral wire

Blue. Completes the circuit.

Live wire

Brown.Is held at a voltage of 230 V and provides the current.

Electricity is a useful form of energy but it can also be very dangerous. There are lots of ways in which we can be electrocuted including:

touching frayed electrical cables, long or overheating cables, damaged or incorrectly wired plugs, allowing water or wet objects to enter plug, sockets or touch frayed cables, pushing metal objects into plug sockets

What are circuit breakers?

Circuit breakers act as resettable fuses.These are automatically operated electrical switches that protect electrical circuits from overloading or short circuiting. They detect faults and then stop the flow of electricity.

conductors and insulators

Conductors allow electricity to flow through them easily. Metals are good examples of electrical conductors. For example, the copper in the wires that connect a television to the plug socket is an electrical conductor. Insulators prevent the flow of electricity. Plastics are good examples of insulators. In the image, the insulator (plastic) surrounds the conductor (copper wire). The insulating plastic stops you getting an electric shock from the wires that carry the electricity.

What are fuses and circuit breakers?

Fuses and circuit breakers protect electrical circuits and appliances.

Earth wire

Green.A safety wire to stop the appliance becoming live. An earthed conductor cannot become live.

current =charge/time

I is the current in amperes (amps), A Q is the charge in coulombs, C t is the time in seconds, s

Where does each wire go?

In a plug, the blue neutral wire goes to the left, the brown live wire to the right and the green and yellow striped earth wire to the top. The fuse fits next to the live wire.

power = current x voltage

P is the power in watts, W I is the current in amperes (amps), A V is the potential differences in volts, V

Doulbe insulation

Some appliances - such as vacuum cleaners and electric drills - do not have an earth wire. This is because they have plastic casings, or they have been designed so that the live wire cannot touch the casing. As a result, the casing cannot give an electric shock, even if the wires inside become loose. These appliances have double insulation.

potential difference

The potential difference (or voltage) of a supply is a measure of the energy given to the charge carriers in a circuit. Units = volts (V). This is the voltage between two points that makes an electric current flow between them

Ohms law- voltage= current x resistance

V is the potential difference in volts, V I is the current in amperes (amps), A R is the resistance in ohms, Ω