Low noise charge ramp electrometer
Abstract
An electrometer capable of measuring small currents without the use of a feedback resistor which tends to contribute a large noise factor to the measured data. The electrometer eliminates the feedback resistor through the use of a feedback capacitor located across the electrometer amplifier. The signal from the electrometer amplifier is transferred to a electrometer buffer amplifier which serves to transfer the signal to several receptors. If the electrometer amplifier is approaching saturation, the buffer amplifier signals a reset discriminator which energizes a coil whose magnetic field closes a magnetic relay switch which in turn resets or zeros the feedback capacitor. In turn, a reset complete discriminator restarts the measurement process when the electrometer amplifier approaches its initial condition. The buffer amplifier also transmits the voltage signal from the electrometer amplifier to a voltage-to-frequency converter. The signals from the voltage-to-frequency converter are counted over a fixed period of time and the information is relayed to a data processor. The timing and sequencing of the small current measuring system is under the control of a sequence control logic unit.
- Inventors:
-
- Idaho Falls, ID
- Issue Date:
- Research Org.:
- WESTINGHOUSE IDAHO NUCLEAR CO
- OSTI Identifier:
- 868489
- Patent Number(s):
- 5153502
- Assignee:
- United States of America as represented by United States (Washington, DC)
- Patent Classifications (CPCs):
-
G - PHYSICS G01 - MEASURING G01R - MEASURING ELECTRIC VARIABLES
- DOE Contract Number:
- AC07-84ID12435
- Resource Type:
- Patent
- Country of Publication:
- United States
- Language:
- English
- Subject:
- noise; charge; ramp; electrometer; capable; measuring; currents; feedback; resistor; tends; contribute; factor; measured; data; eliminates; capacitor; located; amplifier; signal; transferred; buffer; serves; transfer; receptors; approaching; saturation; signals; reset; discriminator; energizes; coil; magnetic; field; closes; relay; switch; resets; zeros; complete; restarts; measurement; process; approaches; initial; condition; transmits; voltage; voltage-to-frequency; converter; counted; fixed; period; time; information; relayed; processor; timing; sequencing; current; control; sequence; logic; unit; voltage-to-frequency converter; control logic; current measuring; relay switch; voltage signal; magnetic field; noise charge; feedback resistor; feedback capacitor; sequence control; measured data; frequency converter; data processor; /324/
Citation Formats
Morgan, John P, and Piper, Thomas C. Low noise charge ramp electrometer. United States: N. p., 1992.
Web.
Morgan, John P, & Piper, Thomas C. Low noise charge ramp electrometer. United States.
Morgan, John P, and Piper, Thomas C. Wed .
"Low noise charge ramp electrometer". United States. https://www.osti.gov/servlets/purl/868489.
@article{osti_868489,
title = {Low noise charge ramp electrometer},
author = {Morgan, John P and Piper, Thomas C},
abstractNote = {An electrometer capable of measuring small currents without the use of a feedback resistor which tends to contribute a large noise factor to the measured data. The electrometer eliminates the feedback resistor through the use of a feedback capacitor located across the electrometer amplifier. The signal from the electrometer amplifier is transferred to a electrometer buffer amplifier which serves to transfer the signal to several receptors. If the electrometer amplifier is approaching saturation, the buffer amplifier signals a reset discriminator which energizes a coil whose magnetic field closes a magnetic relay switch which in turn resets or zeros the feedback capacitor. In turn, a reset complete discriminator restarts the measurement process when the electrometer amplifier approaches its initial condition. The buffer amplifier also transmits the voltage signal from the electrometer amplifier to a voltage-to-frequency converter. The signals from the voltage-to-frequency converter are counted over a fixed period of time and the information is relayed to a data processor. The timing and sequencing of the small current measuring system is under the control of a sequence control logic unit.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1992},
month = {Wed Jan 01 00:00:00 EST 1992}
}