earth wire, live wire, neutral wire, case, pin, fuse, cable grip and outer insulation
1 of 22
case
made from plastic/rubber because they are good electrical insulators
2 of 22
pin (2)
brass (good conductor) compromise from expensive copper, earth pin is the longest
3 of 22
wires (2)
made of copper (good conductor) coated with flexible plastic (good insulator, flexible)
4 of 22
live wire (2)
dangerous (contains main's voltage 230 volts), alternates between +VE and -VE voltage
5 of 22
neutral wire (4)
completes circuit, earthed back at power station, not as high as the live wire, always OV
6 of 22
wiring plugs (4)
right colored wire, firmly screwed, no bare wires, cable grip tightly fastened over cable outer layer
7 of 22
earth wire
safety feature for appliances with metal casing
8 of 22
use for earth wire
If live wire touches appliance without earth wire, person gets an electric shock. If there is the same fault: live wire > metal casing > earth wire > earth, large current flows, fuse melts and cuts off the current
9 of 22
double insulation
appliance with plastic casing, which doesn't need earthing
10 of 22
fuses
melt at a certain current to break and stop the circuit and stop it heating up and damaging the appliance or starting a fire
11 of 22
finding current
current (A) = power (W) / voltage (V)
12 of 22
finding power
power (W) = energy (J) / time (s)
13 of 22
choosing fuses
1A, 3A, 10A, 13A; choose the smallest fuse above the current
14 of 22
electrical hazards (7)
long/frayed cables; cables in contact with something hot/wet; pets or children; water near sockets/shoving things into sockets; damaged plugs/too many in one socket; lighting sockets without bulbs; appliances without covers on
15 of 22
circuit breakers
switches flip open and break circuit when current is too high; close switch to reset
16 of 22
thermal
brass on bi-metallic ***** heats up and bends upward; brass flips down (circuit breaks because of gap); bring brass up to reconnect the circuit
17 of 22
magnetic (MCB)
electromagnet gets very strong, attracts iron bar, turns anti-clockwise, spring flips down, contacts come apart
18 of 22
current
rate of flow of charge
19 of 22
resistor
gets hot if electrical charge flows through, varies the current in a circuit
20 of 22
DC
direct current: always flow in the same direction (battery or cell)
21 of 22
AC
alternating current: repeatedly changes (mains) - UK frequency of 50 cycles/second (hertz)
22 of 22
Other cards in this set
Card 2
Front
made from plastic/rubber because they are good electrical insulators
Back
case
Card 3
Front
brass (good conductor) compromise from expensive copper, earth pin is the longest
Back
Card 4
Front
made of copper (good conductor) coated with flexible plastic (good insulator, flexible)
Back
Card 5
Front
dangerous (contains main's voltage 230 volts), alternates between +VE and -VE voltage
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