2.3 Domestic uses and safety Flashcards
1
Q
2.3.1 Direct and alternating potential difference
What is alternating current?
A
- the current alternates between values, there is a range
- current changes direction
- AC supply is used in mains electricity
- AC supply has a frequency of 50 Hz, and is 230V
2
Q
2.3.1 Direct and alternating potential difference
What is direct current
A
- current flows in **one direction only **
- the power supply can only be high or low (on or off)
- examples are batteries and cells
- can get different voltages
3
Q
2.3.2 Mains electricity
wires and colours in the three-core cable
A
live wire - brown
neutral wire - blue
earth wire - green and yellow stripes
4
Q
2.3.2 Mains electricity
Uses and voltage of live wire
A
- starts the flow of current through the circuit
- 230V from mains supply
- brown coloured wire
5
Q
2.3.2 Mains electricity
Uses and voltage for the earth wire
A
- safety wire to stop the appliance becoming live
- only carries a current if there is a fault in circuit
- 0V (voltage)
- yellow/green coloured wire
6
Q
2.3.2 Mains electricity
Uses and voltage of the neutral wire
A
- electricity flows througout the wire
- completes the circuit from the appliance back to the supply
- 0 V (voltage)
7
Q
2.3.2 Mains electricity
What are the safety features of a plug?
A
- earth wire
- Fuse
8
Q
2.3.2 Mains electricity
What does a fuse do?
A
- acts as a safety system for when the current gets too high
- connected to the live wire
- contains a thin wire that melts when the current gets too high
- once the fuse has melted, the circuit is broken, and no more current flows through the device
- the case of the device is no longer live and there is no more risk of electrocution.
8
Q
2.3.2 Mains electricity
What does a fuse do?
A
- acts as a safety system for when the current gets too high
- connected to the live wire
- contains a thin wire that melts when the current gets too high
- once the fuse has melted, the circuit is broken, and no more current flows through the device
- the case of the device is no longer live and there is no more risk of electrocution.
