P4 - Safe electricals
- Created by: Naomi
- Created on: 21-01-13 17:25
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- Safe electricals
- Resistance
- A measure of how hard it is for current to flow
- Factors that may affect resistance are:
- Length (of wires)
- Material
- Thickness (cross section area)
- Temperature
- Measured in Ohms
- The live wire carries a high voltage around the house
- It is the brown wire
- The neutral wire completes the circuit, providing a return path for the current
- It is the blue wire
- The earth wire is connected to the case of the appliance to prevent it becoming live
- It is the green and yellow wire
- The fuse contains wire which melts if the current becomes too large
- No current can flow, preventing overheating and furthur damage to the appliance
- Earth wires and fuses stop a person receiving an electric shock if they touch a faulty appliance
- The earth wire is connected to the case of the appliance to prevent it becoming live
- It is the green and yellow wire
- As soon as the case becomes 'live', a large current flows in the earth wire and the fuse blows
- The earth wire is connected to the case of the appliance to prevent it becoming live
- A resettable fuse (circuit breaker) doesn't need to be replaced to restore power, it can be reset
- Current
- The flow of electrons
- Measured in amps
- The flow of electrons
- Voltage/potential difference
- A measure of energy carried by an electric current
- Measured in volts
- A measure of energy carried by an electric current
- Electrical power
- The rate at which an appliance transfers energy is its power rating
- power = voltage x time
- The formula for electrical power can be used to calculate the correct fuse to use in an electrical device
- power = voltage x time
- The rate at which an appliance transfers energy is its power rating
- Resistance
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