What does the voltage regulator do?

Answer 1

it controls the amount of voltage that is flowing in a circuit.

To be more accurate, a voltage regulator provides a limiting mechanism to an electrical or electronic power source.

In the case of modern automotive alternators the voltage regulator "regulates" the output from the alternator by limiting the current flowing through the rotating field assembly inside the alternator. The weaker the electromagnetic field of this "rotor" the lower the output (both current and voltage) of the alternator.

When the electrical load on the alternator is low the regulator reduces the field strength based on it's set upper voltage limit. When the load increases beyond the capacity of the "limited" output the voltage drops (the load is kind of "shorting out" the power from the alternator) and the regulator allows the field current (and therefor the output of the alternator) to rise until the voltage reaches that "upper limit" again and so on.

Hope this helps

Answer 2

A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.

Electronic voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. In automobile alternators and central power station generator plants, voltage regulators control the output of the plant. In an electric power distribution system, voltage regulators may be installed at a substation or along distribution lines so that all customers receive steady voltage independent of how much power is drawn from the line.