Current and Voltage

CurrentFlow rate of electricityCurrent flows from + to –Measured in Amps – 1 Amp = 1 Coulomb per secondActually electrons flow in the opposite directionMany electrons make up one coulomb of chargeAll the current flow rate around a circuit is the same. (Current in branches adds up to equal the total current (exception! = capacitors)

Voltage 1 Volt is 1 Joule per CoulombIt is the energy transfer to or from a coulomb of charge

Electro-motive force (EMF)The work done on (energy transferred to) a coulomb of charge by a battery or power supply

Potential DifferenceThe energy level difference between two places

Voltage and currentThe greater the potential difference between two places the higher the current.The ratio voltage:current is resistance ( V = IR )

P = VI