A Power Supply Unit (PSU) in which there is no controlled stabilisation of the voltage output applied electronically. The voltage supplied by a loaded PSU is therefore lower than one which has no load connected due to the increase in output current having a variety of effects, principally through impedance or resistance in the PSU components.
The shorthand term used to denote a standard Universal Serial Bus developed to allow the interconnection of many peripheral devices such as mice, keyboards, joysticks, scanners etc., to a computer such as IBM compatible and Apple PCs. Developed by collaboration amongst leading companies in the computer and electronics industry, the specifications are standardised by the USB Implementers Forum (USB-IF). USB 3 has recently become more readily available and offers speeds up to 5Gbps.