US3660813A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangements for the indication of lamp failure
Assignee: US Philips Corp
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Filing: 1970-04-07
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Granted: 1972-05-02
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Expires: 1990-04-07
Abstract
Abstract An electric warning system for a pair of parallel-connected lamps includes a warning lamp in series with a thyristor across the system input terminals. A resistor is connected in a first series circuit with the lamps and in a second series circuit with a transistor and a capacitor across the input terminals. The transistor is biased to cut-off by means of second and third resistors in series across the input terminals. The circuit components are arranged so that failure of either lamp turns the transistor ''''on'''' to charge the capacitor. The capacitor voltage is coupled to the thyristor control electrode to trigger the thyristor ''''on'''' when a given capacitor voltage level is achieved. A switch is provided in the circuit so as to remove the input voltage from all of the circuit components except the thyristor and the warning lamp.
Inventors
- 👤 Paul Rumpf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:21
CPC Classifications
B; B60; B60Q; B60Q11/00; B60Q11/005
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
209 words
A direct current supply circuit for a first lamp comprising an auxiliary lamp for signaling a failure of the first lamp, a pair of input terminals adapted for connection to a source of DC current, means connecting one input terminal to one end of a diagonal of an electric bridge circuit and the other input terminal to the other end of said bridge diagonal, said bridge including a resistor in three legs of the bridge and the fourth leg of the bridge including at least the first lamp, means connecting the ends of the other bridge diagonal to a main electrode and to the base of a transistor, respectively, means connecting the other main electrode of the transistor through a capacitor to an input terminal, means connecting a junction between said transistor other main electrode and the capacitor to the control electrode of a thyristor, means connecting the auxiliary lamp and the thyristor in series across the input terminals, said bridge resistors being chosen so that with a voltage present across the input terminals and with said first lamp not functioning, the transistor base-emitter junction is forward biased so as to render the transistor conducting and thereby trigger on the thyristor to ignite the auxiliary lamp through the thyristor.
Claim 2
Dependent Claim
209 words
A direct current supply circuit for a first lamp comprising an auxiliary lamp for signaling a failure of the first lamp, a pair of input terminals adapted for connection to a source of DC current, means connecting one input terminal to one end of a diagonal of an electric bridge circuit and the other input terminal to the other end of said bridge diagonal, said bridge including a resistor in three legs of the bridge and the fourth leg of the bridge including at least the first lamp, means connecting the ends of the other bridge diagonal to a main electrode and to the base of a transistor, respectively, means connecting the other main electrode of the transistor through a capacitor to an input terminal, means connecting a junction between said transistor other main electrode and the capacitor to the control electrode of a thyristor, means connecting the auxiliary lamp and the thyristor in series across the input terminals, said bridge resistors being chosen so that with a voltage present across the input terminals and with said first lamp not functioning, the transistor base-emitter junction is forward biased so as to render the transistor conducting and thereby trigger on the thyristor to ignite the auxiliary lamp through the thyristor.
Claim 3
Dependent Claim
60 words
A circuit as claimed in claim 1, further comprising a second lamp connected in parallel with said first lamp and wherein the first lamp and the second lamp are motorcar lamps, said bridge resistors being chosen so that a failure of either of said first and second lamps will forward bias the transistor base-emitter junction to provide said trigger action.
Claim 4
Dependent Claim
70 words
A circuit as claimed in claim 1 further comprising a switch connected between one of the input terminals and the electric bridge, characterized in that one end of the series arrangement of the auxiliary lamp and the thyristor is connected to a point between the switch and the said input terminal so that said series arrangement is connected to the input terminals even in the open condition of the switch.
Claim 5
Dependent Claim
34 words
A circuit as claimed in claim 2 provided in a motorcar and further comprising a switch coupled to the brake of the motorcar and serially connected with the bridge circuit across said input terminals.
Claim 6
Dependent Claim
102 words
A circuit as claimed in claim 1 further comprising a second lamp and a second resistor connected in series therewith across the input terminals to form a second bridge circuit along with the two series legs of the first bridge circuit that include the resistors, first and second diodes, means connecting the first and second diodes between said transistor main electrode and the associated end of the bridge diagonal and the junction of said second lamp and the second resistor, respectively, so that a failure of any one of the main lamps will trigger the thyristor and thereby ignite the auxiliary lamp.
Claim 7
Dependent Claim
50 words
A circuit as claimed in claim 5 further comprising a third lamp connected in parallel with the first lamp and a fourth lamp connected in parallel with the second lamp whereby a failure of any one of the main lamps will trigger the thyristor and thereby ignite the auxiliary lamp.
Claim 8
Dependent Claim
166 words
A DC supply and indicating system for a first lamp comprising, a pair of input terminals adapted for connection to a source of DC current, an auxiliary lamp for signalling a failure in said first lamp, a thyristor connected in series with said auxiliary lamp directly across the input terminals, a first resistor connected in a first series circuit with said first lamp across said input terminals, a transistor and an impedance element connected in a second series circuit with said first resistor across the input terminals, means coupled to said input terminals and to the transistor for biasing the transistor into the cut-off state, means for coupling the voltage derived across said impedance element to the thyristor control electrode for controlling the ignition thereof, said derived voltage being of sufficient magnitude to trigger the thyristor into conduction upon a failure of said first lamp, and a switch connected in series with at least one of said first and second series circuits across the input terminals.
Claim 9
Dependent Claim
166 words
A DC supply and indicating system for a first lamp comprising, a pair of input terminals adapted for connection to a source of DC current, an auxiliary lamp for signalling a failure in said first lamp, a thyristor connected in series with said auxiliary lamp directly across the input terminals, a first resistor connected in a first series circuit with said first lamp across said input terminals, a transistor and an impedance element connected in a second series circuit with said first resistor across the input terminals, means coupled to said input terminals and to the transistor for biasing the transistor into the cut-off state, means for coupling the voltage derived across said impedance element to the thyristor control electrode for controlling the ignition thereof, said derived voltage being of sufficient magnitude to trigger the thyristor into conduction upon a failure of said first lamp, and a switch connected in series with at least one of said first and second series circuits across the input terminals.
Claim 10
Dependent Claim
58 words
A system as claimed in claim 7 further comprising a second lamp connected in parallel with the first lamp, and wherein said biasing means is arranged to allow a substantial current to flow in said transistor upon the failure of either one of said first and second lamps thereby to derive said trigger voltage across said impedance element.
Claim 11
Dependent Claim
14 words
A system as claimed in claim 8 wherein said impedance element comprises a capacitor.
Claim 12
Dependent Claim
72 words
A system as claimed in claim 8 further comprising a first diode connected in series with said first resistor and said transistor, third and fourth lamps connected in parallel, a second resistor and a second diode, means connecting said second resistor and said parallel-connected third and fourth lamps in a third seriEs circuit across the input terminals, and means connecting said second diode in series with said second resistor and said transistor.
Claim 13
Dependent Claim
25 words
A system as claimed in claim 7 for use in a motorcar and further comprising means for coupling said switch to the motorcar brake mechanism.
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) | 1975-05-02 | 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 |