US3705330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic flash circuit for photography
Assignee: Agfa Gevaert AG
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Filing: 1970-01-28
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Granted: 1972-12-05
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Expires: 1990-01-28
Abstract
Abstract An electronic flash unit has a flash tube ignited through an ignition circuit, and a control circuit with a photoelectric element for receiving the light utilized during a photographic process and terminating the light flash after the light has reached a desired value. The operating voltage for the control circuit is furnished from the ignition circuit of the flash tube by connecting one end of the primary winding of the ignition transformer and a tap on said transformer to the control circuit in such a way that the voltage between the two points constitutes the operating voltage for the control circuit.
Inventors
- 👤 Otto Rosenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:29
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
165 words
Electronic flash unit comprising, in combination, a flash tube for generating a light flash, said flash tube having an ignition electrode; an ignition transformer having a secondary winding connected to said ignition electrode, and a primary winding; ignition energy storage means; control circuit means connected to said flash tube for terminating said flash, said control circuit means operating only upon application of an operating voltage; additional storage means connected to said primary winding and said control circuit for furnishing said operating voltage to said control circuit upon occurrence of a determined change of voltage across at least a part of said primary winding; and switch means having a first and second stage for connecting said additional storage means and said primary winding to said ignition storage means upon external activation from said first to said second state, thereby creating said determined change of voltage and for disconnecting said additional storage means and said primary winding from said ignition storage means when in said first state.
Claim 2
Dependent Claim
165 words
Electronic flash unit comprising, in combination, a flash tube for generating a light flash, said flash tube having an ignition electrode; an ignition transformer having a secondary winding connected to said ignition electrode, and a primary winding; ignition energy storage means; control circuit means connected to said flash tube for terminating said flash, said control circuit means operating only upon application of an operating voltage; additional storage means connected to said primary winding and said control circuit for furnishing said operating voltage to said control circuit upon occurrence of a determined change of voltage across at least a part of said primary winding; and switch means having a first and second stage for connecting said additional storage means and said primary winding to said ignition storage means upon external activation from said first to said second state, thereby creating said determined change of voltage and for disconnecting said additional storage means and said primary winding from said ignition storage means when in said first state.
Claim 3
Dependent Claim
19 words
An electronic flash unit as set forth in claim 1, wherein said ignition storage means comprise an ignition capacitor.
Claim 4
Dependent Claim
20 words
An electronic flash unit as set forth in claim 1, wherein said additional storage means comprise a control storage capacitor.
Claim 5
Dependent Claim
51 words
An electronic flash unit as set forth in claim 3, further comprising unidirectional conducting means connected in series with said control storage capacitor, thereby forming a series circuit; and wherein said series circuit is connected in parallel with at least a part of said primary winding of said ignition transformer means.
Claim 6
Dependent Claim
46 words
An electronic flash unit as set forth in claim 4, wherein said unidirectional conducting means is connected to said primary winding and said control storage capacitor in such a manner that current flows to said control storage capacitor substantially simultaneously with closing of said switching means.
Claim 7
Dependent Claim
18 words
An electronic flash unit as set forth in claim 5, wherein said unidirectional conducting means comprise a diode.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-12-05 | 1976-06-05 | 1976-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-05 | 1980-06-05 | 1980-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-05 | 1984-06-05 | 1984-12-05 | $7700.00 | Window Closed / Lapsed |