Therefore, the global practical output tracking of the systems is an important research topic both in theory and practice, that is to say the tracking error is made arbitrarily small within limited time by choosing appropriate design constants,.

Pointing to the problems that exist in the actual-output-capacity calibration of withstanding voltage tester with the half-load-voltage-drop method,the paper firstly analyses the measuring principle of the actual-output-capacity calibration,then emphatically discusses the influence of the testing-voltage and resistor on the actual-output-capacity calibration.