File:Active sign convention new.png

English: Diagram illustrating the active sign convention, the opposite of the passive sign convention, the standard convention used to define the direction of power flow in an electrical component. To comply with this convention, the direction of the voltage v and current i variables in an electric component are defined as shown in the diagram, so that conventional current flows from the negative voltage terminal to the positive. With this convention, positive power flow p (big arrow) will represent power flowing out of the device, that is, power produced in the device. So in a passive (load) component, such as a light bulb or appliance, power dissipation p = iv and electrical resistance R = v / i will be negative, while in an active (source) component, such as a battery or electric generator, power dissipation and resistance will be positive. This convention is not normally used in electrical circuits.