vacuum-tube electrometer

vacuum-tube electrometer

[′vak·yəm ¦tüb ‚i‚lek′träm·əd·ər]
(electronics)
An electrometer in which the ionization current in an ionization chamber is amplified by a special vacuum triode having an input resistance above 10,000 megohms.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.