Voltage Regulator

Voltage regulators are used to regulate, modify or stabilize the output voltage of an alternator or dynamo motor, at the required value. In principle, a voltage regulator is a voltage stabilizer which mechanically stabilizes the ongoing voltage level and keeps it constant at that level despite changes in the supply voltage and load current. A voltage regulator circuit may also be used to modify the voltage level, in accordance with the requirement of the circuit.
 
The Zener diode, a reverse breakdown voltage operational diode supplies a stable voltage reference supply to the voltage regulators. Besides keeping the DC output voltage constant, a voltage regulator has other functions too-  it blocks the AC ripple voltage which cannot be blocked by a filter. A well- engineered voltage regulator may also have extra circuits for defense like short circuits, current limiting circuit, thermal conclusion and over-voltage protection.