Electrical Units (Sections 3a.1 & 3b.2)
Electrical Units |
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Property |
Symbol used in Formulae |
Measured in |
Examples |
|
Electrical Potential Difference or Voltage |
V |
Volts (V) |
A 1.5 Volt Battery, the Mains Voltage is 230 Volts |
|
Current Flow |
I |
Amps (A) |
A measure of the flow of electricity around a circuit |
|
Resistance |
R |
Ohms (Ω) |
Measures the difficulty or opposition to the flow of current. |
|
Power |
P |
Watts (W) |
A 1000 Watt Electric Fire, A 25 Watts Soldering Iron, A 100 Watt Light bulb |
Electrical Potential Difference or Voltage
A 1.5 Volt
Battery. There is a potential difference of 1.5 Volts between the + and –
terminals.
Current Flow
Think of current flow as water flowing through a hosepipe.
Resistance
Resistance reduces current flow. Think of someone bending or crushing a flexible hosepipe so that less water can flow along it.
Power
Power is the effect of multiplying the voltage by the current. A more powerful light is a brighter light; a more powerful radio transmitter can be heard more clearly.