An electrical regulator that is designed to automatically maintain a constant, regular voltage level is a voltage regulator. A voltage regulator may use electromechanical mechanisms, and may use active or passive electronic components. It may also be used to regulate single or several AC/DC voltages dependant on the design.
The modern sort of electronic voltage regulators actually operate in a comparison method of their actual output voltage to internal fixed reference voltage, excepting the passive shunt type of regulators. The percieved differences are amplified and then activated to control regulation elements so that they can reduce voltage errors.
A negative feedback servo control loop device is used to increase the open-loop gain in voltage regulators. This gain can increase regulation accuracy and reduce stability. A trade-off results due to the difference between stability and the speed of the changing response. A low voltage output, maybe due to the reduction of input voltage or the increase in the load current, then the regulation element will produce a higher output voltage. This occurs by decreasing the input voltage for devices like linear series regulators, or, drawing the input current for longer periods, including the boosting type switching voltage regulators.
Normally, a high level output voltage will result in the regulation element will being directed to produce a lower voltage. Notwithstanding, many voltage power regulator possess an over-current protection, which will entirely stop or limit in some way the sourcing current if the output current is too high. Finally, a voltage power regulator can also boot down when the input voltage is outside given parameters.