Patent US2268170A successfully refreshed from Google Patents.
Patent US3132207A successfully refreshed from Google Patents.
US3132207A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microphone amplifier
Assignee: Electratone Inc
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Filing: 1958-05-26
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Granted: 1964-05-05
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Expires: 1978-05-26
Abstract
No abstract record available.
Inventors
- 👤 Eugene D Mccalla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:04
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/181; H03F3/183
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
93 words
IN A MICROPHONE AMPLIFIER HAVING A SOURCE OF CURRENT, A CIRCUIT FOR CONTROLLING MICROPHONE SIGNAL INPUT LEVEL AND AMPLIFIER BIAS LEVEL SIMULTANEOUSLY INCLUDING, A TRANSISTOR AMPLIFIER CONNECTED IN COMMON-EMITTER CONFIGURATION, A VOLTAGE DIVIDER HAVING FIRST AND SECOND ARMS, SAID FIRST ARM BEING CONNECTED TO SAID SOURCE AND INCLUDING A CARBON MICROPHONE AND A VARIABLE RESISTOR, SAID SECOND ARM BEING CONNECTED TO SAID SOURCE AND INCLUDING AN IMPEDANCE COMPONENT, SAID VOLTAGE DIVIDER CONNECTED TO THE INPUT OF SAID TRANSISTOR INTERMEDIATE SAID FIRST AND SECOND ARMS, SAID IMPEDANCE COMPONENT INCLUDING BOTH INDUCTIVE AND RESISTIVE PARAMETERS.
References Cited (Backward Citations)
US2807665A
Cited
US2762870A
Cited
US2784262A
Cited
US2824177A
Cited
US2976369A
Cited
US2857462A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-05-05 | 1967-11-04 | 1968-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-05-05 | 1971-11-04 | 1972-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-05-05 | 1975-11-04 | 1976-05-05 | $7700.00 | Window Closed / Lapsed |