Potential difference can be defined as the difference in the amount of energy that charge carriers have between two points in a circuit. The potential difference (p.d.) is measured in volts (V) and is also known as voltage. Potential difference between any two points is defined as the amount of work done in moving a unit charge from one point to another
Device that helps to maintain a potential difference
Any source of electricity like the battery, cell, power supply, etc. helps to maintain a potential difference across a conductor.