powersupply

A power supply, or power supply unit, provides electrical power to a load. It converts an input source to the voltage, current, and frequency required by the device. Power supplies may draw from AC mains or from batteries, solar, or other sources, and may deliver AC or DC depending on the load; most modern electronics require DC.

Two broad categories are linear and switching power supplies. Linear supplies regulate voltage with a pass element, producing low noise but lower efficiency for large voltage differences. Switching supplies convert input power to a high-frequency form, then rectify and filter to the required output; they are lighter and more efficient at higher powers. They can be enclosed in a chassis, or be external wall adapters or bricks.

Key components include a transformer (in AC-DC types), a rectifier and filter to produce DC, and a regulator to stabilize the output. DC-DC models use switching regulators and inductors. Specifications include output voltage and current, maximum power, regulation, ripple, transient response, efficiency, and protection features such as overvoltage, overcurrent, and thermal shutdown. Many designs use universal input ranges (100–240 V AC) with automatic or manual selection.

Applications span computers, consumer electronics, telecommunications, lab equipment, and industrial systems. Designers balance cost, size, heat, efficiency, noise, and safety. Standards cover insulation, isolation, and protective features, with certifications such as UL, CE, and RoHS common. Reliability depends on component quality, thermal management, and protection circuitry.