Current is defined as 'the flow of electric charge'. It can be broken down into very simple system of electrons, who carry charge, moving around a circuit. Potential difference can be thought of the force that is required to make these electrons move around the circuit. It can almost be considered a pressure that squeezes the electrons, causing current to flow in the circuit. So, whilst Voltage/potential difference is most commonly thought of in circuitry, its actually the current that provides the physical electrical energy to components.