Current
Current is the flow of electric charge (eg. Electrons) around the circuit
Potential difference
Potential difference is the energy transferred per coulomb of charge that passes between two points in an electrical circuit
Resistance
- usually increases with temperature
* when an electrical charge flows through a component it has to work against resistance
Equation for charge
Charge= current x time
Equation for energy transferred
Energy transferred = charge moved x potential difference
Equation for potential difference
Potential difference= current x resistance
What happens when resistance increase?
Temperature usually increases as well
Series circuit
-
Parallel circuit
-
Why is heating a circuit not always bad?
-
Equation for power
Power= energy transferred/ time
E P= — T
Equation for electrical power
P=IV
Electrical power(W) = current (A) x Potential difference (V)
Live wire
- Brown
* the live wire carries the voltage
Neutral wire
- Blue
* the neutral wire completes the circuit
Earth wire
- Green and Yellow
* the earth wire is for safety and protecting the wiring
Fuses
-
Circuit breakers
-
Insulators
-
LDR
Light dependent resistor
•dependent on the intensity of light
•in bright light the resistance falls
•in darkness the resistance is higher
Thermistor
- dependent on temperature
- in hot conditions the resistance drops
- in cool conditions the resistance goes up
