A power supply is used to transform AC voltage into DC voltage. It is clipped into an electrical cabinet. A DC power supply is used to convert 220V single-phase AC into 12 or 24V DC. 

DC power supplies are used to power circuit controls, PLCs, relays, indicators, light rotary switches, etc... 

They are fixed on a DIN rail and some have a modular format (same format as a circuit breaker). 

What is the difference between AC and DC for circuit control? 

Alternating Current: 

Alternating current (AC) is a type of sinusoidal current, like the single-phase 220V in our homes. Rectified by a diode bridge, it can become direct. The power supplies are in fact the very simple transformers, where the ratio of the primary and secondary turns realizes the division of the current.

Direct current: 

Conversely, the direct current (DC) is a current where the electrons flow in the same direction, from the positive pole or negative pole. The power supply has a + terminal (positive) and a - terminal (negative) 

iNORéA offers you a range of DC power supplies in 12 and 24 VDC as well as a cabinet to supply 12 and 24 VDC in 5W to 400W thanks to a single-phase 220V plug.