Unifilar electrometer

From Glossary of Meteorology

unifilar electrometer

An electrostatic type of electrometer that utilizes a single fiber as the sensitive element.

A quartz fiber, coated with conducting material, is mounted midway between two electrical plates, across which a potential is applied. Then a charge is placed on the fiber and its deflection is noted against a scale in the eyepiece of the observing telescope.
Compare bifilar electrometer.