Abstract: A voltage/current source includes a loop controller (24) that digitally determines the control signals that must be applied to a driver amplifier (34) to achieve the desired load voltage or current. The analog outputs of current- and voltage-sensing amplifiers (38 and 68) are converted by analog-to-digital converters (52 and 74) to digital feedback signals that the loop controller (24) uses in determining what control signals to generate. The loop controller (24) keeps the driver-amplifier output voltage equal to the load voltage until switch contacts (30) connect the source to the load so that connection-caused transients are minimized. The loop controller (24) includes read-write memory (25) in which it stores program instructions and operational parameters, so the source can readily change its feedback characteristics.