P2.5 Mains electricty Flashcards
What is a fuse?
A thin wire which is used as a safety device as it melts if too much current passes through it breaking the circuit
What is a fuse’s amp rating?
The largest current that can pass through it
What are the two types of fuse?
1) Cartridge
2) Rewirable
What is a circuit breaker and what does it do?
- Electromagnet switch
- Cuts the circuit when too much current passes through it
What does RCCB stand for?
Residual current circuit breaker
What does an RCCB do?
It detects differences between current in the live and neutral wires
Why is an RCCB good?
- It is fast
- It is more sensitive
What is the equation for energy transferred?
Energy transferred (J) = potential difference (V) x charge (coulombs)
Define potential difference
The difference in electrical energy between two points.
Amount of energy carried by each charge
Define alternating current
The voltage alternates from positive to negative charges
Define frequency
The number of cycles one way and then the other per second
What is the equation for peak voltage
Peak voltage = divisions x timebase (y gain)
What is the blue cable in a plug ad where does it go?
It is neutral and it goes on the left
What is the striped (green and yellow) cable in a plug and where does it go?
It is the earth cable and it goes at the top
What is the brown cable in a plug and where does it go?
It is the live cable and it goes on the right
