What does electrometer mean?
An electrometer is a scientific instrument used to measure electric charge or potential difference. Unlike a voltmeter, which draws a small current to take its reading, a classical electrometer relies almost entirely on electrostatic forces — for example, the repulsion between charged leaves or plates — so it can detect extremely small quantities of charge without disturbing the system being measured. Instruments of this kind, including the gold-leaf electrometer and Lord Kelvin's quadrant electrometer, played a crucial role in nineteenth- and early-twentieth-century physics: they were essential to studies of atmospheric electricity and to early research into radioactivity, where experimenters such as Marie Curie used them to gauge the faint ionization produced by radioactive materials. Modern electrometers are highly sensitive electronic devices capable of measuring minuscule currents and charges, and they remain standard equipment in laboratories working with semiconductors, radiation, and precision electrical measurements. The word belongs chiefly to technical and scientific registers rather than everyday conversation.
nounAn instrument for measuring electric charge or potential difference, especially one in which the measurement depends on electrostatic forces rather than on current flow.
- An instrument for measuring electric charge, potential difference, or ionization current, typically relying on electrostatic force rather than current flow.
"The researchers used a sensitive electrometer to detect the tiny charges accumulated on the insulated sphere."
"Curie's experiments with radioactivity depended on an extremely delicate electrometer to measure the ionization produced in air."
"The technician connected the electrometer to the capacitor to verify that no residual charge remained before servicing the device."
Standard regular plural, used when referring to multiple instruments or different models.
"The laboratory keeps several electrometers calibrated for work at nanovolt sensitivities."
Before modern digital meters, physicists measured electricity with a gold leaf so light that a whisper of static charge could make it move.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of electrometer
The word electrometer was formed in the late eighteenth century from Greek-derived elements: 'electro-', from the Greek 'elektron' meaning amber (the substance in which static electricity was first observed), combined with '-meter', from the Greek 'metron' meaning measure. The same 'meter' element appears in cognates such as barometer, thermometer, and diameter, all coined to name instruments or units of measurement. The term arose during the period when natural philosophers were developing the first quantitative tools for studying electricity, replacing earlier purely qualitative detectors.
How electrometer is actually used
A technical term used mainly in physics, electrical engineering, and laboratory contexts; it is rare in everyday speech. In historical scientific literature it often refers to instruments such as the gold-leaf and quadrant electrometers, which are now largely obsolete but still discussed in the history of science.
Easily confused with electrometer
An electroscope merely detects the presence of electric charge, whereas an electrometer measures its magnitude quantitatively.
A galvanometer measures small electric currents by their magnetic effects, while an electrometer measures charge or potential difference by electrostatic means.