Linear Power Supply

A linear power supply always includes the following elements :

• An electric transformer the purpose of which is to lower the voltage drawn from your electricity grid in order to provide your device with a suitable voltage.
• A rectifier bridge, that is generally already mounted on the PCB of your power supply. It plays a major role in the AC to DC conversion.
• A (or many) capacitor(s) for smoothing the output voltage curve as to make the power output as linear as possible.
• A voltage regulator for stabilizing the voltage even when the circuit or electricity grid is subjected to variations.

Power supply module

As a rule of thumb, the rectifier bridge, the capacitors and the voltage regulator are all gathered on a single PCB. The convention is to call this PCB a "Power Supply Module".