What is Voltage?

The Voltage is the difference in electric potential between those two points. The difference in voltage measured when moving from point A to point B is equal to the work which would have to be done, per unit charge, against the electric field to move the charge from A to B. The 'Volt' (V) is the unit of voltage. Instrument used for measuring voltage is Voltmeter.

Potential difference and electro motive force:

To have flow of electrons or electricity between the two ends of a conductor, the difference of electric pressure is necessary. The difference of electric pressure is known as potential difference. Rate of flow of electricity or current strength depends upon the potential difference. Greater the potential difference, the greater will be the current strength, lessor the potential difference, lesser the current strength. No potential difference, no current.

‘The potential difference is that which causes the current to flow in a closed circuit.’

The electromotive force (e.m.f.) of a source is the potential difference between the terminals of the source when no current is drawn from it i.e. when the source is in the open or infinite resistance circuit.

The potential difference is the difference of voltage between the terminals when the load is connected with the source. The unit of potential difference in practical as well as in mks (or SI) system of units is volt.

Are Voltage and Current Related?

Voltage and current are not the same thing, although they are closely related. In simple terms, Voltage causes Current. Given a Voltage and a path for the electrons, current will flow. Given the path, but no Voltage, or Voltage without the path, there will be no current.