Patent US3683205A successfully refreshed from Google Patents.
US3683205A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Logarithmic converter
Assignee: United Kingdom Atomic Energy Authority
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Filing: 1971-02-16
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Granted: 1972-08-08
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Expires: 1991-02-16
Abstract
Abstract A semi-conductor device comprises an n-type substrate carrying a base electrode, and two diffused-in regions of p-type material which respectively carry an emitter electrode and a collector electrode. The construction is in the form of a lateral transistor and the collector electrode is preferably arranged to be relatively remote from the emitter electrode so as to give a very low collector current gain. Under these conditions, the emitter-base voltage of the device is dependent on the natural logarithm of the input current to the collector electrode over a wide range. An amplifier keeps the collector-base voltage low compared with the emitter-base voltage.
Inventors
- 👤 Eliot Patrick Fowler
- 👤 Richard William Greaves
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:26
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/24
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
90 words
An electrical circuit arrangement providing an exponential relationship between an input signal and an output signal, comprising a lateral transistor having a base electrode, an emitter electrode and a collector electrode, the collector junction being diffused into and completely surrounded by the base, means for feeding the input signal to the collector electrode in the form of a current, and circuit means connected to the transistor for maintaining the collector-base voltage at a minimal level so that the emitterbase voltage is dependent on the natural logarithm of the input current.
Claim 2
Dependent Claim
90 words
An electrical circuit arrangement providing an exponential relationship between an input signal and an output signal, comprising a lateral transistor having a base electrode, an emitter electrode and a collector electrode, the collector junction being diffused into and completely surrounded by the base, means for feeding the input signal to the collector electrode in the form of a current, and circuit means connected to the transistor for maintaining the collector-base voltage at a minimal level so that the emitterbase voltage is dependent on the natural logarithm of the input current.
Claim 3
Dependent Claim
23 words
A circuit arrangement according to claim 1, in which the collector current gain of the transistor is a very small fraction of unity.
Claim 4
Dependent Claim
47 words
A circuit arrangement according to claim 2, in which the circuit means comprises an amplifier having a high input impedance and connected between the collector and emitter electrodes of the transistor so as to maintain the collector-base voltage of the transistor low compared with the emitter-base voltage.
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) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |