Patent US3660682A successfully refreshed from Google Patents.
US3660682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current limiting circuit
Assignee: AG Communication Systems Corp
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Filing: 1971-02-01
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Granted: 1972-05-02
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Expires: 1991-02-01
Abstract
Abstract The disclosure includes a transistor connected in the signal applying path of a telephone trunk circuit. The transistor is connected into a circuit configuration of resistors to operate as a voltage controlled ''''negative-resistance'''' shunted by the resistors which absorb the excess power during adverse line conditions. The overall voltage-current circuit characteristics very closely approximate the traditional ballast lamp.
Inventors
- 👤 Todd H Gartner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:32
CPC Classifications
H; H03; H03G; H03G11/00; H03G11/002; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
173 words
A transistor circuit for limiting the current to a variable resistance load connected to the output terminal of the circuit, comprising in combination: a DC voltage source comprising a negative voltage terminal and a positive voltage terminal, an output terminal, a first voltage divider including a first and a second resistor, said voltage divider connected in series between said first DC voltage source negative terminal and said output terminal, a second voltage divider including a third and a fourth resistor, said second voltage divider connected in series between said DC voltage source negative terminal and said DC voltage source positive terminal, a transistor having base, collector and emitter electrodes, said collector electrode connected to said output terminal, said emitter electrode connected to the junction of said first and second resistors of said first voltage divider and said base electrode connected to the junction of said third and fourth resistors of said second voltage divider, and a fifth resistor, said fifth resistor connected between said DC voltage source negative terminal and said output terminal.
Claim 2
Dependent Claim
173 words
A transistor circuit for limiting the current to a variable resistance load connected to the output terminal of the circuit, comprising in combination: a DC voltage source comprising a negative voltage terminal and a positive voltage terminal, an output terminal, a first voltage divider including a first and a second resistor, said voltage divider connected in series between said first DC voltage source negative terminal and said output terminal, a second voltage divider including a third and a fourth resistor, said second voltage divider connected in series between said DC voltage source negative terminal and said DC voltage source positive terminal, a transistor having base, collector and emitter electrodes, said collector electrode connected to said output terminal, said emitter electrode connected to the junction of said first and second resistors of said first voltage divider and said base electrode connected to the junction of said third and fourth resistors of said second voltage divider, and a fifth resistor, said fifth resistor connected between said DC voltage source negative terminal and said output terminal.
Claim 3
Dependent Claim
65 words
A transistor circuit as defined in claim 1, wherein said second voltage divider resistors have such values that the voltage drop across the resistors remains substantially constant, and said first voltage divider resistors have such a value that the voltage drop across the second resistor increases with increasing load current, said transistor operated by said increased voltage across said second resistor to conduct less current.
References Cited (Backward Citations)
US3251951A
Cited
FR1503948A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |