Energy Flashcards
what is a short circuit?
Path of low resistance for current
what is a fuse?
electrical component with a low melting point, high resistance conductor
what is melting point?
tempreture at which substance melts
Advantages of circuits in parallel? (3)
- if one light fuses, rest will still work due to having its own parallel path
- other appliances still work if one is faulty
- current does not diminish if more lights switched on at same time.
dis advantage of circuit in parallel
parallel circuits can cause over loads on mains.
what is a circuit breaker?
electromagnetic switch that breaks circuit when current too high
how does the electromagnetic switch break?
high current makes magnetic field of electromagnet open switch
where is an electromagnetic switch found?
fusebox
what is a fuse made up of?
2 terminals and see through insulating materials
how does a fuse work?
short circuit overload (excess current) creates heat which melts fuse wire which stops current flowing in circuit
what are the 3 wires in a 3 pin plug?
brown(live), blue(nuetral), yellow/green(earth)
what is the function of the brown(live) wire?
carries alternating current
what is the function of the blue(nuetral) wire?
completes circuit (zero voltage)
what is the function of the yellow/green(earth) wire?
connected to appliance metal casing and goes into ground. if appliance charged by fault the earth wire discharges current as it has no resistance.
Safety precautions when wring a plug(4)
1. brown to L yellow/green to- E blue to N 2. fuse with correct value 3.no bare/loose wires 4. cable grip firm