Meanwhile it can test 78 and 79 series three-terminal voltage regulator. The tester has adopted the large scale integrated circuit for analogue/digital conversion. With high sensitivity and accuracy, it adopts liquid crystal display which can be read directly. With compact structure and convenient operation, it is portable and especially suitable for inspection and screening of devices and components in electronic factories as well as application of technicians engaged in electronic work, lab staff, maintainers and radio fans.