The Complete Circuit

Source, path and load each have a different role.

The voltage source—such as a battery—establishes an electrical potential difference. The conductive path provides a continuous route through wires and component terminals. The load receives power and converts it into light, heat, motion, sound or signal processing.

A light bulb or motor is a clear load. In a complex electronic circuit, combinations of resistors, capacitors, transistors and integrated circuits shape both energy and information.

Continuous current requires a loop.

A path that leaves the source but does not return is open; it cannot sustain continuous current. Close the switch and the electric field is established around the circuit. Charge already present in the conductors begins to drift throughout the loop.

In a metallic conductor electrons drift from the negative terminal toward the positive terminal. Conventional current is defined in the opposite direction. Both descriptions refer to the same circuit behaviour, but diagrams normally use conventional current unless stated otherwise.

The load does not consume electrons.

Electrons circulate through the conductive path; the load transfers energy from the electrical system into another form. Saying a resistor “uses the energy of the electrons” is a useful first intuition, but charge is conserved. The source restores energy to the circuit charge while the load removes energy per unit charge.