Patent US3287723A successfully refreshed from Google Patents.
US3287723A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital voltmeters
Assignee: Gemalto Terminals Ltd
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Filing: 1965-07-27
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Granted: 1966-11-22
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Expires: 1985-07-27
Abstract
No abstract record available.
Inventors
- 👤 Metcalf Eric
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:01
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
134 words
A DIGITAL VOLTMETER COMPRISING IN COMBINATION: AN OPERATIONAL AMPLIFIER HAVING AN INPUT CIRCUIT AND AN OUTPUT CIRCUIT; A CAPACITIVE FEEDBACK NETWORK COUPLED BETWEEN SAID OUTPUT AND INPUT CIRCUITS; AN INPUT TERMINAL ADAPTED TO RECIEVE AN INPUT VOLTAGE; FIRST SWITCHING MEANS COUPLED BETWEEN SAID INPUT TERMINAL AND SAID INPUT CIRCUIT OF SAID AMPLIFIER FOR PROVIDING TO SAID INPUT CIRCUIT AN ELECTRIC CHARGE PROPORTIONAL TO SAID INPUT VOLTAGE; A SOURCE OF REFERENCE VOLTAGE; SECOND SWITCHING MEANS; A RESISTIVE FEEDBACK NETWORK CONNECTED BETWEEN SAID OUTPUT AND INPUT CIRCUITS, SAID SECOND SWITCHING MEANS COUPLING SAID SOURCE OF REFERENCE VOLTAGE AND SAID RESISTIVE FEEDBACK NETWORK TO THE INPUT OF SAID AMPLIFIER, SAID SECOND SWITCHING MEANS BEING OPERABLE TO SIMULTANEOUSLY CONNECT SAID REFERENCE VOLTAGE SOURCE TO SAID INPUT CIRCUIT OF SAID AMPLIFIER AND ALSO TO ESTABLISH SAID RESISTIVE FEEDBACK NETWORK;
Claim 2
Dependent Claim
134 words
A DIGITAL VOLTMETER COMPRISING IN COMBINATION: AN OPERATIONAL AMPLIFIER HAVING AN INPUT CIRCUIT AND AN OUTPUT CIRCUIT; A CAPACITIVE FEEDBACK NETWORK COUPLED BETWEEN SAID OUTPUT AND INPUT CIRCUITS; AN INPUT TERMINAL ADAPTED TO RECIEVE AN INPUT VOLTAGE; FIRST SWITCHING MEANS COUPLED BETWEEN SAID INPUT TERMINAL AND SAID INPUT CIRCUIT OF SAID AMPLIFIER FOR PROVIDING TO SAID INPUT CIRCUIT AN ELECTRIC CHARGE PROPORTIONAL TO SAID INPUT VOLTAGE; A SOURCE OF REFERENCE VOLTAGE; SECOND SWITCHING MEANS; A RESISTIVE FEEDBACK NETWORK CONNECTED BETWEEN SAID OUTPUT AND INPUT CIRCUITS, SAID SECOND SWITCHING MEANS COUPLING SAID SOURCE OF REFERENCE VOLTAGE AND SAID RESISTIVE FEEDBACK NETWORK TO THE INPUT OF SAID AMPLIFIER, SAID SECOND SWITCHING MEANS BEING OPERABLE TO SIMULTANEOUSLY CONNECT SAID REFERENCE VOLTAGE SOURCE TO SAID INPUT CIRCUIT OF SAID AMPLIFIER AND ALSO TO ESTABLISH SAID RESISTIVE FEEDBACK NETWORK;
References Cited (Backward Citations)
US3188455A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-11-21 | 1970-05-23 | 1970-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-11-21 | 1974-05-23 | 1974-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-11-21 | 1978-05-23 | 1978-11-22 | $7700.00 | Window Closed / Lapsed |