Programmable power supplies are digitally controlled power supply source equipment used for powering electronics circuits that require adjustable and variable AC/DC voltage/current. Programmable power supplies are usually the laboratory instruments to provide flexible and adjustable power supply to various testing applications. Programmable power supplies allow for remote control of the AC/DC output voltage/current through an analog input signal or PC bus interface ports such as USB, GPIB (IEEE-488), RS-232, RS-485, and Ethernet LAN (LXI) using computer software. Programmable power supplies are used for automated testing and monitoring of electrical equipment in production and industrial applications.

Sources of electrical energy are an integral part of the instrumentation system, including a programmable power supply. Because most electronic products require variable and adjustable power to test them accurately for experimental and laboratory work. Many applications require more than a fixed voltage. Today’s test systems and industrial processes require stable and accurate control of output voltage and current during operation with the facility to monitor these parameters. Programmable power supplies also come in a variety of forms including modular, board-mounted, wall-mounted, floor-mounted or bench top.

Programmable power supplies are composed of a microprocessor or microcontroller, voltage/current programming circuits, current shunt, and voltage/current read-back circuits. Programmable power supply circuits are designed to provide DC/AC voltage/current, voltage/current frequency, different shapes of voltage waveforms (sinewaves, pulse voltage squarewaves, etc.), short circuit protection, overload protection, over-current and temperature compensation, etc. Programmable power supplies can furnish DC, AC, or AC with a DC offset. AC output can be single phase and three phases, namely a single phase is used only for applications that require low voltage, and three-phase power is usually used for applications that require high voltage.