US3566266A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Voltmeter
Assignee: NAT INSTR LAB Inc
•
Filing: 1967-03-09
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Granted: 1971-02-23
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Expires: 1987-03-09
Abstract
Abstract A SEMICONDUCTOR DIFFERENTIAL OPERATIONAL AMPLIFIER RESPONDS TO THE SOURCE BEING MEASURED AND FEEDS A METER. THE AMPLIFIER INPUT OFFSET CURRENT IS BALANCED AS A FUNCTION OF TEMPERATURE BY CONNECTING ONE OF THE AMPLIFIER INPUTS TO A FEEDBACK RESISTANCE HAVING A VALUE APPROXIMATELY EQUAL TO THE SERIES RESISTANCE OF THE SOURCE AND A LARGE RESISTANCE, CONNECTED TO THE OTHER AMPLIFIER INPUT. THE INPUT AND FEEDBACK RESISTANCES ARE FILTERED TO REMOVE STRAY A.C. PICKUP SO THAT THE RESPONSE TIME OF THE METER IS ON THE ORDER OF 2 SECONDS. THE SOURCE BEING MEASURED IS CONNECTED TO GROUND THROUGH A BUCKING VOLTAGE.
Inventors
- 👤 Abraham Bloom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:13
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/0023
Claims Analysis
Total Claims: 0
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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) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |