- A voltage regulator is a current limiter. So a voltage regulator of 12 volts limits the current to 12 volts. To prevent the light bulbs from burning through under too strong electricity. An alternating current remains an alternative. AC voltage remains AC voltage in this voltage regulator. It can not be used to charge a battery. A direct current also remains a direct current, but is also limited / regulated. These voltage regulators are often used on old mopeds without indicators, battery etc. There is only one input and one output.
* A rectifier (usually a diode bridge) corrects the 12-volt alternating current at + and -12 volts. This current can therefore be used, for example, for charging a battery, a horn … This current is therefore rectified but also regulated, usually at 13.2 volts (voltage to charge a battery). There are also rectifier controllers in 6 volts version.