US4197484A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic flash device with voltage display
Assignee: West Electric Co Ltd
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Filing: 1978-04-17
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Granted: 1980-04-08
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Expires: 1998-04-17
Abstract
Abstract An electronic flash device comprising a DC-DC converter circuit which converts a low voltage DC source to a high voltage DC current for charging a main discharge capacitor, a flash discharge tube which is adapted to flash by means of the energy stored in the main discharge capacitor, and a display circuit. The DC-DC converter circuit includes an oscillation transformer having a primary winding, a secondary winding magnetically connected with the primary winding, an auxiliary winding and further a second auxiliary winding, an oscillation transistor, and an auxiliary capacitor connected with the auxiliary winding for causing the oscillation transistor to be started; and the display circuit is lit for display when the voltage generated across the second auxiliary winding and the voltage applied across the auxiliary capacitor are superposed to reach a predetermined value.
Inventors
- 👤 Kazuo Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:01
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; G; G03; G03B; G03B15/00; G03B15/02; G03B15/03; G03B15/05
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
152 words
An electronic flash device comprising: a DC-DC converter which includes an oscillation transformer having a primary winding, a secondary winding, an auxiliary winding and a second auxiliary winding; an oscillation transistor, and an auxiliary capacitor connected with the auxiliary winding for causing the oscillation transistor to be started and converts a low voltage DC source to a high voltage DC current for charging a main discharge capacitor, a flash discharge tube which is adapted to flash by means of the energy stored in the main charge capacitor, and a display circuit comprising a diode and resistor means connected in series with a light emitting diode wherein the voltage generated across said second auxiliary winding is superposed on the voltage charged on said auxilliary capacitor, and means for applying resultant superposed voltage to said display circuit whereby said light emitting diode emits light in response to the voltage appearing across said resistor means.
Claim 2
Dependent Claim
152 words
An electronic flash device comprising: a DC-DC converter which includes an oscillation transformer having a primary winding, a secondary winding, an auxiliary winding and a second auxiliary winding; an oscillation transistor, and an auxiliary capacitor connected with the auxiliary winding for causing the oscillation transistor to be started and converts a low voltage DC source to a high voltage DC current for charging a main discharge capacitor, a flash discharge tube which is adapted to flash by means of the energy stored in the main charge capacitor, and a display circuit comprising a diode and resistor means connected in series with a light emitting diode wherein the voltage generated across said second auxiliary winding is superposed on the voltage charged on said auxilliary capacitor, and means for applying resultant superposed voltage to said display circuit whereby said light emitting diode emits light in response to the voltage appearing across said resistor means.
Claim 3
Dependent Claim
19 words
A device according to claim 1, wherein said light emitting diode is connected in parallel with a first resistor.
Claim 4
Dependent Claim
14 words
A device according to claim 2, wherein said first resistor comprises a variable resistor.
Claim 5
Dependent Claim
35 words
A device according to claim 1, wherein said second auxiliary winding is provided on the secondary side of said transformer, and said display circuit is connected through said second auxiliary winding across said auxiliary capacitor.
Claim 6
Dependent Claim
126 words
An electronic flash device comprising: a DC-DC converter which includes an oscillation transformer having a primary winding, a secondary winding, an auxiliary winding and a second auxiliary winding; an oscillation transistor, and an auxiliary capacitor connected with the auxiliary winding for causing the oscillation transistor to be started and converts a low voltage DC source to a high voltage DC current for charging a main discharge capacitor, a flash discharge tube which is adapted to flash by means of the energy stored in the main charge capacitor, and a display circuit connected to the auxiliary capacitor and second auxiliary winding which indicates when the combination of the voltage generated across the second auxiliary winding and the voltage applied across the auxiliary capacitor reaches a predetermined value.
Claim 7
Dependent Claim
126 words
An electronic flash device comprising: a DC-DC converter which includes an oscillation transformer having a primary winding, a secondary winding, an auxiliary winding and a second auxiliary winding; an oscillation transistor, and an auxiliary capacitor connected with the auxiliary winding for causing the oscillation transistor to be started and converts a low voltage DC source to a high voltage DC current for charging a main discharge capacitor, a flash discharge tube which is adapted to flash by means of the energy stored in the main charge capacitor, and a display circuit connected to the auxiliary capacitor and second auxiliary winding which indicates when the combination of the voltage generated across the second auxiliary winding and the voltage applied across the auxiliary capacitor reaches a predetermined value.
References Cited (Backward Citations)
US3831079A
Cited
US4068150A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-08 | 1983-10-08 | 1984-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-08 | 1987-10-08 | 1988-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-08 | 1991-10-08 | 1992-04-08 | $7700.00 | Window Closed / Lapsed |