Download The electron-volt

Current and Voltage
Current
Flow rate of electricity
Current flows from + to –
Measured in Amps – 1 Amp = 1 Coulomb per
second
Actually electrons flow in the opposite direction
Many electrons make up one coulomb of charge
All 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 Coulomb
It 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 Difference
The energy level difference between two places
Voltage and current
The greater the potential difference between two
places the higher the current.
The ratio voltage:current is resistance ( V = IR )
P = VI