Unit 6 Flashcards
Where is AC usually found
Mains electricity
What is the frequency of mains in the U.K.
50Hz
Where is DC found
battery
Give examples of hazards in the home
1) long cables
2) frayed cables
3) water near sockets
4) damaged plugs
5) too many plugs in one socket
What is the Brown wire?
Live wire
What is the blue wire?
Neutral wire
What is the green and yellow wire?
earth wire
What does the earthwire do?
if something was to go wrong it carries the electrical current to the earth
What does a fuse do?
- if a fault develops with the live wire touching the metal case, the case is earthed
- this ‘trips’ the circuit breaker which cuts off the live supply and breaks the circuit
What does double insulated mean?
If a a plug has a plastic coating with no metal parts showing it is said to be ‘double insulated’
What don’t you need if you have a double insulated plug?
an earth wire isn’t needed
What does a circuit breaker do?
• when it detects a fault they break the circuit by opening a switch
What are the advantages and disadvantages of using a circuit breaker rather than a fuse
+ easily reset (fuses have to be replaced when melted)
- more expensive
What is an RCCB
Residual Current Circuit Breaker
What is the Plum Pudding?
- John Dalton agreed atoms were tiny spheres
- 100 years later J. J. Thompson discovered electrons could be removed from atoms so created the plum pudding
