DC Supply

A power supply is an electrical device that converts electric current from a power source to the correct voltage, current, and frequency to power the load.

Type of power supply:

DC Power Supply
A DC power supply is equipment that supplies a constant DC voltage to its load. Depending on requirement, a DC power supply may be powered from an AC source or a DC Source then regulated to match the correct voltage, current, and frequency to power the load.

Rectifier
A Rectifier is used to charge a battery or series of batteries and also provide DC power to the DC load. Rectifier use AC power as main source, and when AC power is down, the rectifier circuit automatically switch to battery as main power to supply the DC load without interruption. An uninterruptible power supply (UPS) consists of a rectifier circuitry includes battery.

Battery charger
Battery Charger has similar functionality to a rectifier but normally does not provide automatic switchover circuitry when main power is down.

Inverter
An Inverter is a circuitry that changes DC voltage to AC voltage.
The inverter does not produce any power; the power is provided by the DC source.