An instrument used to measure voltage or electric potential difference; also called [[伏特计|伏特計|fu2 te4 ji4]] or [[电压计|電壓計|dian4 ya1 ji4]].

An instrument used to measure voltage or electrical potential difference; also called [[伏特计|伏特計|fu2 te4 ji4]] or [[电压表|電壓表|dian4 ya1 biao3]].

the voltage difference required between the inputs of an amplifier to set the output to zero