Domestic electricity Flashcards
To revise domestic electricity (paper 1)
State the typical voltage for mains electricity?
230 V
State the frequency of mains electricity
50 Hz
Define a.c.
Alternating current, the electrons vibrate backwards and forwards. Mains electricity use a.c.
Define d.c.
Direct current. Electrons only flow in one direction. This is what we get from batteries
State the names and colours of the 3 wires found inside a cable.
Live wire - Brown
Neutral wire - Blue
Earth wire - Green and yellow stripes
Which wire can be missing from some appliances? Why?
Earth wire, if the appliance is plastic and you cannot get an electric shock from it.
State the role of the line wire
To carry the alternating potential difference from the supply to the component. the potential difference between the live and the earth is 230 V
State the role of the neutral wire
The neutral wire complete the circuit from the component back to the supply. The neutral wire is at or close to 0V
State the role of the Earth wire.
It is a safety wire to stop an appliance becoming live. the earth wire is at 0V as it only carries a current if there is a fault.
State the relationship between power, potential difference and current.
Power = potential difference x current P = VI
State the units of power
Watts (W)
State the units of potential difference
Volts (V)
State the units of current
Amperes (A)
State the relationship between power, resistance and current.
Power = (Current)squared x resistance
State the units for resistance
Ohms
