Why is electricity related to voltage?

Answer 1

Because voltage is the power that makes electricity to circulate in a wire. Depending on the diameter, the lenght and material of the conductor (wire) the current, (the amount of electrons) flowing in the wire, the resistance will be lower or higher. Conclusively, the voltage is not the electricity itself, but it is like a pump that impulses the water through a pipe. Electricity is the current whose unit of measurement is the Ampere.

So you have the voltage, resistance, and current in a electrical circuit on a direct current system.