The electric power used for lights and fuel pumps is produced by a bike's generator. The regulator takes this power and maintains the voltage at a constant level. The Smart Regulator Kawasaki developed for small-displacement models features a built-in microprocessor, enabling control of the charging function and the headlamp. This control enables charging to be done even at idling speed, when the voltage generated is at its lowest, (provided conditions are standard and no accessories are being used), which exceeds the ability of current regulators. Additionally, once the battery is fully charged, or when the throttle is opened quickly, the smart regulator turns the charging function off, instantly reducing the electrical resistance of the generator. This enables the energy used to drive the generator to be saved – usually a big loss, especially for a small-displacement engine. By minimising power loss, the Smart Regulator contributes to increased fuel efficiency.