Mains electricity Flashcards
What are the differences between Alternating current (ac) and direct current (dc)?
- Alternating current repeatedly reverses
- Direct Current is in one direction
What is meant by the peak voltage of an alternating potential difference?
the maximum measured voltage from 0 volts.
What is the difference between the live wire and the neutral wire?
- Neutral wire: stays at 0 volts
- Live wire: repeatedly changes from + to - voltage every cycle
what is the formula for the frequency of an ac
time taken for 1 cycle
what are the colours of the three wires?
- Earth: green and yellow
- live: brown
- Neutral: brown
why is plastic used to house plug sockets?
Plastics are good electrical insulators
why do we use a three pin plug?
one pin for each wire, the longest being earth.
what is the mains cable made of?
three copper wires, all insulated and sleeved in more plastic insulation forming one wire.
what will a fuse do if the current is to great?
melt
a circuit breaker will trip when there’s too much current, how does this happen?
if a certain amount of current flows through the circuit breaker an electromagnet switch will open and break the circuit.
An RCCB switches off when?
the live wire current is different to the neutral wire.
The energy transferred to an appliance each second is known as
the power supplied to that device
An electric current is known as what?
The flow of charge
charge is measured how?
in coulombs
Why are electrical faults dangerous?
- They can cause electrical shocks
- They can cause fires
