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A unit of electromotive force defined as the potential difference across a conductor when a current of 1 ampere dissipates 1 watt of power. Used as the universal measure of electrical 'force' across the World, it was named in honour of the Italian physicist Allessandro Volta who invented the first chemical battery. Its precise value was fixed by the 18th General Conference on Weights and Measures in 1948 and is maintained internationally for practical measurement by the US National Institute of Standards and Technology (NIST) through the development of the Josephson junction array chip.
An electronic circuit composed of discrete components or packaged in an Integrated Circuit, which is designed to render the output voltage of a PSU or other device, constant irrespective of load applied. A simple semiconductor example is a zener diode but many more complex designs are now available at a range of output values and powers such as those incorporated into the 7800 and 7900 series IC regulators.