A current regulator is at work each time a cell phone is recharged, a car is started, a computer is plugged in, or a small electrical appliance is turned on. Sometimes called voltage regulators, current regulators reduce and limit the amount of electricity to a level that is required for the electrical device to operate. Standard house current in the United States (US) is 110 volts, which is 240 volts in the United Kingdom and much of Europe. Many electrical devices, however, only require a fraction of the incoming voltage — this is where a current regulator comes into play.
Generally, a current regulator is a form of step-down transformer that allows only a set amount of current to pass through to the device. For example, computers typically require only 20 volts to operate and cell phones require only 3 volts. Current regulators in both cases are usually part of the cord that is plugged into the wall and then into the device.
Most all current regulators for consumer appliances include circuitry for constant current regulation. This circuitry keeps the current going to the device at a constant level to avoid damage. Since household voltage can fluctuate slightly due to variations in overall utility capacity or drains on the building's electrical system, this kind of fluctuation can cause sensitive devices to malfunction or cease to operate. The constant current circuit takes the available voltage and stabilizes it to a constant and reliable low-voltage level.
The simplest kind of current regulator is a voltage regulator, which functions only as a step-down transformer. It contains no constant current circuitry, as is used for more robust devices that are designed to operate within acceptable ranges of voltage fluctuations. Common types include those found in the starting systems of some automobiles, large appliances, machinery, and voltage transformers used by travelers abroad.
Most of the common current regulator devices consumers us require no manual voltage settings or other interaction. Universal current regulators are typically equipped with switches for the user to change the output voltage to power a variety of different devices. Commercial and industrial current regulators are installed on certain types of machinery where the changing or adjustment of differing voltages is necessary for various stages of machinery operation. These are commonly used to vary the speed of motors to power equipment, but operate on the same principle of converting standard current to lower levels.