A New Way in the Development of Electronic Electrometers with a Varicap-Diode Modulator

In this paper, the theoretical studies and adopted technical solutions relative to an electronic electrometer with a varicap-diode modulator are described. The electrometer has an input resistance of 1014 ¿at 1-V input. The use of this electrometer technique and the performance limitations which may be obtained are analyzed. In order to overcome the usual input resistance of the varicap-diode modulator, reverse polarization of the bridge diodes is used. This provides an increase in input modulator resistance of about 15 times.