Electrical Principles

Electrical Principles


Power (in watts) = Volts x Current (in amps)

so with a bit of algebra , I = p/v   so a 20 watt lamp at 12 volts would pull 1.6 amps,  but a 20 watt lamp at domestic mains voltage of 240 volts would pull less that 0.1 amp.


 Volts = Current (in amps) * Resistance (in Ohms)