voltage regulator is an electrical or electronic device that keeps the voltage of a power source within acceptable limits. The voltage regulator is required to keep voltages within the acceptable range for electrical equipment that uses that voltage. If the supply voltage changes or fluctuates across a certain range, a voltage stabiliser helps to stabilize or regulates the voltage. During over and under voltage conditions, it is an electrical device that feeds a steady voltage to a load. It's an electrical device that protects electrical devices like air conditioners and computers from damage caused by voltage fluctuations by providing constant voltage current.