Electricity in the home Flashcards
What are the 2 types of electricity supplies?
Alternating current(ac) and direct current(dc)
In ac supplies how is the current like?
It’s constantly changing direction
What are alternating currents produced by?
Alternating voltages in which the positive and negative ends keep alternating.
What is the UK mains supply around?
230V
What is the frequency of the ac mains supply?
50 cycles/second or 50Hz
What are cells and batteries supply?
Direct current(dc)
What is direct current?
current that always flows in the same direction
What is dc created by?
direct voltage
Most electrical appliances are connected to the mains by 3-core cables,what does the coloured plastic coating mean?
The colour of the insulation on each cable shows its purpose.
The colours are always the same for every appliance,so it is easy to tell the different wires apart.
What is the live wire?
It’s brown and provides the alternating potential difference(at about 230V)from the mains supply.
What is the neutral wire?
It is blue and completes the circuit -when the appliance is operating normally,the current flows through the live and neutral wires.It’s around 0V.
What is the earth wire?
It is green and yellow.It is protecting the wiring and for safety-it stops the appliance casing from becoming live.
It doesn’t usually carry a current-only when there is a fault.It’s also at 0V.
Why are live wire dangerous?
Can cause large electric shock which can be fatal due to the potential difference.
Any connections between live and earth can be dangerous.If the link creates a low resistance path to earth and huge current will flow(lead to a fire)
