also: ボルトメーター
noun
voltameter
A scientific instrument for measuring electric charge via electrolysis. Not to be confused with a voltmeter (電圧計), which measures voltage. The gloss 'voltmeter' is likely a common error or loose usage.
ボルタメーターを使って、電気分解で生じた気体の量を測定した。
Using a voltameter, we measured the amount of gas produced by electrolysis.
A voltmeter measures voltage, while a voltameter measures electric charge through electrolysis. The similar names often cause confusion.
Borrowed from English 'voltameter', coined from 'voltaic' + '-meter'.