P17: Household Electricity Flashcards
Direct Current
Electric current in a circuit that is in one direction only.
Alternating Current
Electric current in a circuit that repeatedly reverses its direction.
What is the mains frequency in the UK?
50Hz (AC)
Live wire
The mains wire that has a voltage that alternates between +325 and -325v (in Europe)
Neutral Wire
The wire of a mains circuit that is earthed at the local substation so its potential is close to zero.
Half wave rectification
The use of a diode in a circuit with an alternating supply pd to allow current in only one direction every other half cycle of the supply pd.
Socket
A mains socket is used to connect the mains plug of a mains appliance to the mains circuit.
What are plug pins made of?
Brass (Its a good conductor, and it doesn’t rust or oxidise)
What is the longest pin of a three-pin plug and why?
The earth plug, because it is the first pin that connects with the wall socket, so the plug is earthed even before the other pins connect.
Fuse
A fuse contains a thin wire that melts and cuts the current off if too much current passes through it.
What does the earth wire protect?
The user
What does the fuse protect?
The appliance and the wires of a circuit.
Circuit Breaker
An electromagnetic switch that opens and cuts the current off off if too much current passes through it.
Why are circuit breakers better than fuses?
They work faster
They can be reset
