Electric potential ($\varphi$)

In electrostatics the electric field is $E=-\nabla \Phi$, where $\Phi$ is the electric potential.

Electric potential, often referred to as voltage, is a measure of the potential energy per unit charge at a specific point in an electric field. It indicates how much work would be needed to move a positive test charge from a reference point (commonly taken as infinity or a grounded point) to the point in question, without any acceleration.