Electric current flows in a circuit due to the movement of electric charge, typically carried by electrons. When a power source, such as a battery or generator, is connected to a circuit, it creates a difference in electric potential (voltage) between two points. This difference pushes the electrons through the conductive material, usually wires, which compose the circuit.
In a closed circuit, where there is a continuous path for the electrons to travel, the current flows from the negative terminal of the power source, through the circuit, and back to the positive terminal. The flow of current can be visualized kind of like water flowing through pipes; a pressure difference (voltage) causes the flow, and the circuit acts as the pipe that channels the flow.
Additionally, the amount of current that flows is influenced by the resistance of the circuit components; higher resistance results in less current flow for a given voltage, following Ohm’s Law (I = V/R). Understanding this basic principle helps in designing electrical systems and troubleshooting circuit issues.