Patent US3577335A successfully refreshed from Google Patents.
US3577335A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Feedback circuit for anodizing thin-film resistors
Assignee: AT&T Inc
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Filing: 1968-05-09
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Granted: 1971-05-04
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Expires: 1988-05-09
Abstract
Abstract A THIN-FILM RESISTOR, WHICH IS TO BE ANODIZED TO INCREASE ITS RESISTANCE TO A PRESELECTED VALUE IS CONNECTED TO ONE ARM OF A BRIDGE CIRCUIT. AS THE RESISTOR IS BEING ANODIZED AND INBALANCE INTHE BRIDGE DRIVES A MONITOR CIRCUIT WHICH CONTROLS A VARIABLE RESISTANCE IN SERIES WITH A SUPPLY OF ANODIZING VOLTAGE. AS THE THIN-FILM RESISTOR BEING ANODIZED APPROACHES THE PRESELECTED VALUE, THE BRIDGE BECOMES MORE NEARLY BALANCED AND THE VARIABLE RESISTOR INCREASES IN VALUE TO INTERRUPT THE FLOW OF ANODIZING CURRENT.
Inventors
- 👤 Frank H Blitchington Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:53
CPC Classifications
C; C25; C25D; C25D21/00; C25D21/12
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) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |