electricity in the home

alternating current

constantly changes direction, produced by alternating voltages in which the positive and negative ends keep alternating

direct current

always flows in the same direction, created by direct voltage

examples of direct current

batteries and cells

example of alternating current

mains supply

voltage and frequency of mains electricity?

230V and has a frequency of 50Hz

what material are the pins from a plug made of?

brass

what is the live wire?

brown and carries the ac from the supply and is dangerous

what is the neutral wire?

blue and completes the circuit, usually is set at 0V, ac still flows through it

what is the earth wire?

green and yellow, safety wire set at 0V and doesn’t usually carry current but if there is a fault the ac flows from live to the earth

what does the fuse do?

if there is a fault that causes too much current flow, the fuse melts and breaks the circuit

why are the pins made from brass?

good conductivity, good durability, resistant to corrosion

what is retification?

the conversion of ac to dc using a diode to only allow one-way flow of electrons

what is the national grid?

a giant system of cables and transformers that cover the UK and connects power stations to consumers

what are transformers?

things that increase (step up) or decrease (step down) the voltage

what voltage and current does the national grid use?

high voltage and low current

why is a high current not used?

energy loss as the wires heat up and energy is transferred to the thermal energy of the surroundings