P5 Electricity in the Home Flashcards
Direct current:
Where the electric current only flows in 1 direction
Alternating current:
Where the electric current changes direction.
Which type of current is the electricity from plug sockets in the UK?
Alternating current
What are the measurements of the Mains?
50 Hz
230V
Live Wire:
- Brown
- 230V
- Alternating PD from mains
Earth Wire:
- Green and yellow
- 0V
- Only carries current if the is a faulyt.
- Safety wire to stop the appliance from becoming live.
Neutral Wire:
- Blue
- Same or close to earth wire PD (0V)
- Completes circuit and carries current away from appliance.
Power equations:
Power = PD x Current
Power = Current^2 x resistance
Energy transferred equations:
Energy transferred = power x time
Energy transferred = charge x PD
The National Grid Order:
- Power station
- Step up transformer
- Transmission cables
- Step down transformer
- Houses
What does a step up transformer do?
- PD is increased
- Current is decreased
- Reduces thermal energy dissipated to surroundings.
- Increases efficiency
What does a step down transformer do?
- PD is decreased
- Current is increased
- Makes it safe for use
What are fuses?
Fuses contain thin wires that melt if the current flowing through an appliance is too high.
What are the fuse ratings?
3A, 5A, 13A
What do circuit breakers do?
The same thing as fuses except they can be used more than once.
