A voltage regulator is a component or circuit that keeps output voltage close to a desired value. It helps protect electronics from voltage changes that could cause errors or damage.
Why voltage regulation matters
Chips, sensors, displays, and microcontrollers often need a specific voltage such as 5 V, 3.3 V, or another regulated level. A changing battery or adapter voltage may not be stable enough by itself.
Linear and switching regulators
Linear regulators are simple and quiet but can waste more heat. Switching regulators are more efficient and common in power supplies, but they are more complex. Both may appear after a rectifier in an AC-powered device.
A regulator is the part that helps make power predictable.