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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 21:10 |
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Conference: Bucharest University Faculty of Physics 2003 Meeting
Section: Electricity and Biophysics
Title:
High Input Impedance Differential Amplifier
Authors:
Vlad Antohe and Liviu Giurgiu
Affiliation:
Faculty of Physics, University of Bucharest
E-mail
Keywords:
Abstract:
The aim of this paper, is to designe an analog voltmeter to be used for the measure of differential voltages in the 0 - 200 V range, generated by very high input impedance (over 100 Mohmi) in the power supply devices.
The input of the differential stage was made by a double triode ECC40 with very small residual grid current (< 1 pA). The input impedance of this voltmeter can be varied in very large scale from 1 Gohm to 1 Tohm. Using three Operational Amplifiers BM324, the device transforms the high input differential voltage in a low asymmetric output voltage easy to be measured (0 - 2 V range).
The frequency bandwidth of the high input impedance differential amplifier is about 10 Hz (for 1 Tohm input impedance).
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