Abstract: The front-panel design of traditional voltmeter is improved and thus the voltmeter watch is made,which is able to not only measure the electric voltage, but also the current of oneself. In the experiment of characteristic of volt-ampere, the new voltmeter can be used in spite of electric resistance, all adopt the ammeher circumscribes. The voltmeter can be used to measure current of oneself, so that the voltage and current accurately of the electronic device can be measured.

Key words: current of full deflection, number of scale mark, split-current