Shielded electrometer whose output is used to control width of pulses fed back to the shield and associated battery test circuitry

摘要

An electrometer having reduced spacing sensitivity, with the electrometer including a probe with a charge receiving sensor element and a surrounding shield. A voltage equivalent to that sensed by the probe element is fed back to the shield to render the electrometer substantially spacing insensitive. A duty cycle control regulates the width of electrical pulses to a power transformer whose output is fed back to the probe shield to maintain the spacing insensitivity. Means are also provided to automatically test and calibrate the electrometer prior to use.