The unit of potential is the Volt, named after Alessandro Volta


the 1st cinema in Dublin 1904 founded by James Joyce was called the Volta.

Batteries are a source and sink of charged bodies,

So this Voltage story is based on the fact that electrons are attracted to positive charge. Seeing as electrons are so small they do most of the moving. They leave the place where they are the particle in the majority, they are attracted to the place where they are in the minority.

That is electrons leave a place where there are loads of other electrons and go to a place where there are very few electrons (in other words a shortage of electrons (a 'positively' charged place).

Voltage can be seen as the height above ground that the charged particles are held above. The greater this potential the great the energy of the particles will be. Voltage is often called Potential Difference and both are measured in Volts. The idea of voltage (potential difference) is like the idea of potential energy in Mechanics

Voltage drops (like waterfalls)

If there is no drop then there is no driving force for the electricity to be driven along with.

the flow of … is caused by a difference in …

a river (liquid water) altitude

the wind (air) atmospheric pressure

heat (internal energy) temperature

In Biology, substances are transfer through cells by Osmosis

dissolved substances (solutes) concentration



  1. Charges exist.
  2. Charges exert forces on each other.
  3. This force appears to exert itself across distances of any size.

a force causes motion

Measuring Voltage across

Generate different voltages


Circuit symbols