In electronics, a sensitive voltage measuring device based on a null technique which provides infinite impedance at null.
In chemistry, potentiometric methods involve the measurement with a potentiometer of voltage generated in a cell. A high impedance digital voltmeter is often used today as a convenient alternative to a potentiometer.
Source: PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2207 (https://doi.org/10.1351/pac199062112167)