Patent EP0164439A1 successfully refreshed from Google Patents.
US3265979A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drift-free d. c. amplifier
Assignee: Coleman Instruments Corp
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Filing: 1962-06-01
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Granted: 1966-08-09
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Expires: 1982-06-01
Abstract
No abstract record available.
Inventors
- 👤 John J J Staunton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:48
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/38; H03F3/40
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
189 words
AN IMPROVED PERIODICALLY SELF-CORRECTED DRIFT-FREE D.C. AMPLIFIER CIRCUIT COMPRISING D.C. AMPLIFIER MEANS HAVING PAIRS OF INPUT AND OUTPUT TERMINALS, A SIGNAL INPUT CIRCUIT HAVING FIRST AND SECOND CIRCUIT PATHS OF APPLYING A D.C. SIGNAL TO THE INPUT TERMINALS OF SAID AMPLIFIER MEANS, SAID FIRST SIGNAL INPUT CIRCUIT PATH COMPRISING A MEMORY CAPACITOR CONNECTED TO ONE INPUT TERMINAL OF SAID AMPLIFIER MEANS, AND SAID SECOND SIGNAL INPUT CIRCUIT PATH COMPRISING A FEEDBACK RESISTANCE CONNECTED TO THE SECOND INPUT TERMINAL OF SAID AMPLIFIER MEANS, INDICATING MEANS FOR THE AMPLIFIED D.C. SIGNAL CONNECTED TO ONE OUTPUT TERMINAL OF SAID AMPLIFIER MEANS, A NEGATIVE FEEDBACK LOOP CONNECTING SAID INDICATING MEANS TO ONE TERMINAL OF SAID FEEDBACK RESISTANCE REMOTE FROM TO ONE TERMINAL INPUT TERMINAL, A COMMON TERMINAL CONNECTING THE OTHER INPUT TERMINAL OF SAID AMPLIFIER MEANS AND SAID SECOND OUTPUT TERMINAL, AND SWITCHING MEANS FOR PERIODICALLY SWITCHING SAID MEMORY CAPACITOR OUT OF SAID FIRST SIGNAL INPUT PATH AND ACROSS SAID FEEDBACK RESISTANCE OUTPUT AND THEN SWITCHING CAPACITOR FROM THE AMPLIFIER OUTPUT AND THEN SWITCHING SAID MEMORY CAPACITOR BACK TO SAID FIRST SIGNAL CIRCUIT PATH TO COMPENSATE FOR ANY DRIFT IN SAID AMPLIFIER MEANS.
Claim 2
Dependent Claim
189 words
AN IMPROVED PERIODICALLY SELF-CORRECTED DRIFT-FREE D.C. AMPLIFIER CIRCUIT COMPRISING D.C. AMPLIFIER MEANS HAVING PAIRS OF INPUT AND OUTPUT TERMINALS, A SIGNAL INPUT CIRCUIT HAVING FIRST AND SECOND CIRCUIT PATHS OF APPLYING A D.C. SIGNAL TO THE INPUT TERMINALS OF SAID AMPLIFIER MEANS, SAID FIRST SIGNAL INPUT CIRCUIT PATH COMPRISING A MEMORY CAPACITOR CONNECTED TO ONE INPUT TERMINAL OF SAID AMPLIFIER MEANS, AND SAID SECOND SIGNAL INPUT CIRCUIT PATH COMPRISING A FEEDBACK RESISTANCE CONNECTED TO THE SECOND INPUT TERMINAL OF SAID AMPLIFIER MEANS, INDICATING MEANS FOR THE AMPLIFIED D.C. SIGNAL CONNECTED TO ONE OUTPUT TERMINAL OF SAID AMPLIFIER MEANS, A NEGATIVE FEEDBACK LOOP CONNECTING SAID INDICATING MEANS TO ONE TERMINAL OF SAID FEEDBACK RESISTANCE REMOTE FROM TO ONE TERMINAL INPUT TERMINAL, A COMMON TERMINAL CONNECTING THE OTHER INPUT TERMINAL OF SAID AMPLIFIER MEANS AND SAID SECOND OUTPUT TERMINAL, AND SWITCHING MEANS FOR PERIODICALLY SWITCHING SAID MEMORY CAPACITOR OUT OF SAID FIRST SIGNAL INPUT PATH AND ACROSS SAID FEEDBACK RESISTANCE OUTPUT AND THEN SWITCHING CAPACITOR FROM THE AMPLIFIER OUTPUT AND THEN SWITCHING SAID MEMORY CAPACITOR BACK TO SAID FIRST SIGNAL CIRCUIT PATH TO COMPENSATE FOR ANY DRIFT IN SAID AMPLIFIER MEANS.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-08-08 | 1970-02-07 | 1970-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-08-08 | 1974-02-07 | 1974-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-08-08 | 1978-02-07 | 1978-08-09 | $7700.00 | Window Closed / Lapsed |