A voltage regulator is a system designed to automatically maintain a constant voltage level. It maintains the voltage of a power source within acceptable limits. It includes (Step-Down) Buck converter and (Step-Up) Boost Converter. voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. A voltage regulator may use a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism or electronic components, depending on the design.