How is voltage (potential difference) established in a circuit?

Voltage, or potential difference, is established in a circuit by a source of electrical energy such as a cell or battery.

Inside a cell, chemical reactions occur that create a separation of charges: one terminal becomes positively charged, and the other becomes negatively charged. This difference in charge creates an electric potential between the two terminals.

When the circuit is completed, this potential difference drives the flow of electrons from the negative terminal to the positive terminal through the external circuit, resulting in electric current.

In simple terms, voltage acts as the driving force that pushes charges through a conductor.