US3774188A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical indicating circuits
Assignee: Individual
•
Filing: 1972-03-24
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Granted: 1973-11-20
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Expires: 1992-03-24
Abstract
Abstract Lamp monitoring and failure indicating circuits are described which employ normally non-conducting semiconductor switches. The circuit potential sensed across a resistor connected to the monitored lamp biases a transistor OFF, holding a second transistor OFF. Thus in normal operation of the lamp the circuit draws no current. A fault turns both transistors ON.
Inventors
- 👤 W Bial
- 👤 M Mcdonnell
- 👤 G King
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:21
CPC Classifications
B; B60; B60Q; B60Q11/00; B60Q11/005
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
160 words
An electrical circuit for mobile vehicles to monitor any of a plurality of lamps, said circuit including: a resistive element connected in series with each of said lamps, a normally nonconductive transistor means connected to the junction of each of said lamps and its associated resistive element to be biased conductive by the failure signal potential developed at such junction when that lamp fails, biasing means for said transistor means including at least one diode, said biasing means connected to said transistor means for setting the potential drop between the base and the emitter of said transistor means, said bias being substantially insensitive to temperature variations, a normally non-conductive semiconductor switch means arranged to be biased conductive whenever the transistor means conducts, AND circuit means coupled to said transistor means for determining actuation of said switch means by said lamp failure signals, and an electrical indicating device connected to be operated by said switch means when the transistor means conducts.
Claim 2
Dependent Claim
160 words
An electrical circuit for mobile vehicles to monitor any of a plurality of lamps, said circuit including: a resistive element connected in series with each of said lamps, a normally nonconductive transistor means connected to the junction of each of said lamps and its associated resistive element to be biased conductive by the failure signal potential developed at such junction when that lamp fails, biasing means for said transistor means including at least one diode, said biasing means connected to said transistor means for setting the potential drop between the base and the emitter of said transistor means, said bias being substantially insensitive to temperature variations, a normally non-conductive semiconductor switch means arranged to be biased conductive whenever the transistor means conducts, AND circuit means coupled to said transistor means for determining actuation of said switch means by said lamp failure signals, and an electrical indicating device connected to be operated by said switch means when the transistor means conducts.
Claim 3
Dependent Claim
49 words
An electrical circuit as claimed in claim 1 wherein the transistor means is a single multi-emitter transistor having each of the emitters individually and directly connected to a different one of the junctions of said lamps and individually associated resistive elements, and said AND circuit means includes said emitters.
Claim 4
Dependent Claim
58 words
An electrical circuit as claimed in claim 1 wherein the transistor means includes a plurality of p-n-p transistors, the emitter terminal of each of said transistors connected to a different one of the junctions of said lamps and individually associated resistive elements, and a supply line, the collector of each of said transistors connected to said supply line.
Claim 5
Dependent Claim
41 words
An electrical circuit as claimed in claim 1 wherein a pair of series connected resistors is connected between the collector of the transistor means and a supply line, the junction of the said resistors connected to bias said semiconductor switch means.
Claim 6
Dependent Claim
62 words
An electrical circuit as claimed in claim 1 wherein the semi-conductor switch means comprises a n-p-n transistor, the collector circuit of said n-p-n transistor including said indicating device and the base-emitter junction of the n-p-n transistor connected across at least one resistor, whereby in use the potential developed across the resistor when the transistor means is conductive biases the n-p-n transistor ON.
Claim 7
Dependent Claim
56 words
An electrical circuit as claimed in claim 1 wherein the second semiconductor switch means comprises a switching device operable in either a conductive or a non-conductive state, and wherein the device is in use operated to change from a non-conductive to a conductive state by the potential appearing across a resistor whenever the transistor means conducts.
Claim 8
Dependent Claim
33 words
An electrical circuit as claimed in claim 6 wherein an integrating device is connected to the semiconductor switch means to indicate the length of time elasped since failure of one of said lamps.
Claim 9
Dependent Claim
144 words
An electrical circuit for monitoring and indicating lamp failure in any one or more of a plurality of lamps in mobile vehicles, comprising: a resistive element connected to each of said lamps, a normally non-conducting sensing transistor connected to a different one of the junctions of each of said lamps and said resistive element connected thereto, first potential divider means connected to and providing the base potentials of each of the sensing transistors, a first diode and a resistive element constituting said first potential divider means for each transistor, a second diode connected to the collector of each transistor, second potential divider meaNs connected to said second diode, a normally non-conducting semiconductor switch means having a control terminal and output terminal, the control terminal of said switch means connected to said second potential divider means, and a warning/indicating device connected to said output terminal.
Claim 10
Dependent Claim
144 words
An electrical circuit for monitoring and indicating lamp failure in any one or more of a plurality of lamps in mobile vehicles, comprising: a resistive element connected to each of said lamps, a normally non-conducting sensing transistor connected to a different one of the junctions of each of said lamps and said resistive element connected thereto, first potential divider means connected to and providing the base potentials of each of the sensing transistors, a first diode and a resistive element constituting said first potential divider means for each transistor, a second diode connected to the collector of each transistor, second potential divider meaNs connected to said second diode, a normally non-conducting semiconductor switch means having a control terminal and output terminal, the control terminal of said switch means connected to said second potential divider means, and a warning/indicating device connected to said output terminal.
Claim 11
Dependent Claim
27 words
An electrical circuit as in claim 8 wherein said warning/indicating device includes an electrolytic cell to indicate the period of time said warning/indicating device has been actuated.
Claim 12
Dependent Claim
18 words
An electrical circuit as in claim 8 wherein said normally non-conducting semiconductor switch means comprises a silicon-controlled rectifier.
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) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |