English: Diagram showing current flow through an electrical load such as a resistor, light bulb, electric motor, or other passive electrical device. The electric current flows into the positive terminal and out of the negative terminal. The charges move under the influence of the electric field E in the direction of lower electric potential (voltage). The charges perform work on the component and lose potential energy (color). Therefore electric power p > 0 flows out of the circuit and into the component (yellow arrows).

This contrasts with an active device, an electric power source such as a electric generator or battery. In an active device the current is forced to flow into the negative terminal and out of the positive terminal, in the direction of increasing electric potential. Therefore work is done on the charges, they gain potential energy, and electric power flows out of the component into the circuit. A companion source animation is located at Electric power source animation.gif