US3644828A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dc high-voltage follower electrometer
Assignee: United States Department of the Navy
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Filing: 1970-05-19
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Granted: 1972-02-22
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Expires: 1990-05-19
Abstract
Abstract A high-input impedance electrometer tube for measuring highatmospheric electric potentials where the high-input impedance is provided by a guard voltage (equal to the atmospheric voltage measured) supplied by a charged capacitor capable of large positive and negative excursions.
Inventors
- 👤 Stuart G Gathman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:32
CPC Classifications
G; G01; G01W; G01W1/00; G01W1/16; G01R; G01R1/00; G01R1/30; G01R29/00; G01R29/12; G01R29/24; G01R5/00; G01R5/28
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
192 words
Apparatus for providing a high guard voltage to a measuring device whereby a low current, high voltage may be measured by said measuring device, comprising: an antenna for detecting a voltage; a metallic guard around said antenna; an electrometer tube amplifier means comprising an anode, grid and filament electrodes, said grid connected to said antenna; operational amplifier means having a first input, a second input and an output, means coupling the filament electrode of the electrometer tube amplifier means to the first input of the operational amplifier means, capacitive means for storing a voltage level with respect to ground potential, means for applying positive and negative voltages to said capacitor in response to the voltage differential appearing between the metallic guard and the voltage level at the output of the operational amplifier means, means coupling the voltage level appearing on the capacitor to the metallic guard, and to the second input whereby the voltage at said second input of the operational amplifier means is approximately the same as the voltage at said first input of said operational amplifier means, and output means connected to the metallic guard for supplying a measurable voltage.
Claim 2
Dependent Claim
192 words
Apparatus for providing a high guard voltage to a measuring device whereby a low current, high voltage may be measured by said measuring device, comprising: an antenna for detecting a voltage; a metallic guard around said antenna; an electrometer tube amplifier means comprising an anode, grid and filament electrodes, said grid connected to said antenna; operational amplifier means having a first input, a second input and an output, means coupling the filament electrode of the electrometer tube amplifier means to the first input of the operational amplifier means, capacitive means for storing a voltage level with respect to ground potential, means for applying positive and negative voltages to said capacitor in response to the voltage differential appearing between the metallic guard and the voltage level at the output of the operational amplifier means, means coupling the voltage level appearing on the capacitor to the metallic guard, and to the second input whereby the voltage at said second input of the operational amplifier means is approximately the same as the voltage at said first input of said operational amplifier means, and output means connected to the metallic guard for supplying a measurable voltage.
Claim 3
Dependent Claim
91 words
Apparatus as recited in claim 1 wherein said supplying means comprises: two voltages supplies, one of said voltage supplies having its negative terminal connected to said capacitor, the other of said voltage supplies having its positive terminals connected to said capacitor; and two relays between said voltage supplies and capacitor having normally open switches; whereby said relays charge said capacitor by closing their respective switches upon a predetermined voltage between said second input and said output of said operational amplifier and complete the connection of said voltage supplies to said capacitor.
Claim 4
Dependent Claim
56 words
Apparatus as recited in claim 2 Including: insulating material between said antenna and said metallic guard; a filament battery for heating said filament; two batteries connected to said tube anode; and a rheostat connected to said tube filament for adjusting the voltage at said first input of said operational amplifier to the voltage on said antenna.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-21 | 1975-08-23 | 1976-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-21 | 1979-08-23 | 1980-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-21 | 1983-08-23 | 1984-02-22 | $7700.00 | Window Closed / Lapsed |