A power limiter, often called a power source limiter, is a device that is responsible for limiting the amount of power that is supplied to electrical devices. There are a number of synonyms that are commonly used to describe a power limiter including current limiter, voltage regulator, and electricity restricter. A current limiter is a device that restricts the flow of electric current to a predetermined value while a voltage regulator limits the voltage output supplied to a device. Electricity restricter or controller is a generic term that encompasses a wide range of devices designed to regulate the flow of electric current, including power limiters.