Power supplies convert any form of energy, be it mechanical, chemical or solar, to electrical energy that can supply power to any electrical load. These devices have a power input that receives energy from the source, and an output consisting of electrical, wireless or hardwired circuit connectors, to supply the load with electricity. These devices come in many types. Batteries, chargers, renewable and some other types produce direct current (DC), which is a unidirectional flow of electric charge, and low-voltage power. Many devices require more power than what DC provides, and as such, there is a need to convert DC to alternating current (AC), where polarity or flow of the electric current changes direction periodically, generating much higher power. There are several AC/DC power supplies in the market, such as industrial power DC/AC supplies. Switched-mode power supplies (SMPS) have a switching regulator that controls the conversion of electrical power very efficiently. Power supplies also come in many forms and models, and are highly differentiated. Many power supplies are stand-alone units, whereas others come fitted to larger devices. Lighting is another major category of electrical devices. Lighting technology consists of components such as electroluminescence panels, LED fittings and modules, LED drivers and others, all used to power light bulbs, LEDs and other light sources.