This instrument is designed with constant signal source inherent resistance. It ensures that the voltage applied on the same measured part or the current signal does not change as the measurement range is adjusted. For this purpose, it avoids the phenomena that it is difficult for instrument to select the measurement range of the measured part located at the borderline of the measurement range.
This instrument has the key lock function and the status-holding function. It avoids the false operation and meanwhile, the instrument with customization of individual character has the default function when it is started up.