1 INTRODUCTION

1 INTRODUCTION

A power supply is a device that supplies electrical energy to one or more electric loads.  The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy (e.g., mechanical, chemical, solar) to electrical energy. A regulated power supply is one that controls the output voltage or current to a specific value the controlled value is held nearly constant despite variations in either load current or the voltage supplied by the power supply's energy source.

2 LINEAR REGULATED POWER SUPPLY

The voltage produced by an unregulated power supply will vary depending on the load and on variations in the AC supply voltage. For critical electronics applications linear regulator may be used to set the voltage to a precise value, stabilized against fluctuations in input voltage and load. The regulator also greatly reduces the ripple and noise in the output direct current. Linear regulators often provide current limiting, protecting the power supply and attached circuit from over current.