To make an electric current flow, what is necessary?

For electric current to flow, a voltage difference is necessary. Voltage, measured in volts, is a measure of electric potential energy per unit charge. This difference in voltage creates an electric field that pushes charged particles, such as electrons, through a conductor. Without this potential difference, there would be no driving force to move the charges, thus preventing any current from flowing.

In practical terms, if you imagine a water system, voltage difference can be likened to the pressure difference that causes water to flow through pipes. Just as water needs pressure to move, electric current requires a voltage difference to enable charged particles to travel through a circuit.

While a conductor is important for current to flow, it must exist alongside a voltage difference; simply having a conductor alone, without voltage, will not lead to a flow of electric current. Similarly, a ground connection and a source of heat are not essential requirements for current flow in the basic sense of electric circuits, although they can play roles in specific electrical systems or applications.