Voltage regulators are electromechanical components that maintain a consistent output of volts, which are units of electromotive force. Electric or electronic components are often made to accept certain maximum voltages and can be badly damaged by power surges. Low voltage, on the contrary, might not provide enough power for the components to function. Regulators keep the voltage within the range that the components can safely accept and use to function properly.
In Electronic Devices
A computer is an example of an electronic device that requires a voltage regulator. The regulator transmits the voltage from the computer's power supply at a level that will not damage the microprocessor. A computer might need more than one regulator, depending on the system. Some computers use special programmable regulators that interface with the microprocessor to ensure a specific voltage level.
In Automobiles
Cars also use voltage regulators within the system that maintains the battery's charge. Regulators usually are part of the car's alternator, although many cars, particularly older cars and modern American models, have exterior voltage regulators. Alternators or generators are used to generate power, which is fed into the car's battery to maintain a full charge. The power generated by the car's charging system is also used to run the car's electrical systems, such as its headlights, stereo, power windows and ventilation systems.
The car's alternator or generator has a pulley on one side that is turned by one of the engine's drive belts; the force of the engine is used to run the alternator or generator. The engine's speed varies during acceleration and shifting gears, so voltage regulators are needed to control the output produced by the alternator or generator. Without a regulator, the engine could produce an excessively high voltage output when the car is being driven at faster speeds, sending a surge through the system, overcharging the battery and damaging the car's electrical systems. A very low voltage output might not produce enough power to maintain the battery's charge and run the car's electronic systems, creating a load on the battery and potentially reducing the battery's life.
Replacing Regulators
When voltage regulators stop working, they need to be replaced. Regulators for computers or other basic household electronics are available through dealers that specialize in electronic components. For cars, voltage regulators are available from dealerships or aftermarket parts stores. Some cars might have external voltage regulators, in which case they can be purchased separately and easily replaced. Most cars' voltage regulators are inside the alternator, however, so the owner would need to buy a new alternator or rebuild the existing alternator with a new voltage regulator.