US3742297A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for controlling the discharge of a capacitor
Assignee: Rollei of America Inc
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Filing: 1970-12-28
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Granted: 1973-06-26
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Expires: 1990-12-28
Abstract
Abstract A flash tube triggering capacitor and triggering transformer primary winding are connected in series across power supply resistors to charge the capacitor. The anode-cathode circuit of an SCR is connected across the series combination of the capacitor and winding. A bypass capacitor, a bias resistor, and the terminals of a hot shoe are connected in series across one of the power supply resistors. The gate-cathode circuit of the SCR is connected across the bias resistor. The terminals of a PC connector are connected across the series combination of the hot shoe terminals and the bypass capacitor. The completion of an electrical path between either the hot shoe terminals or the PC terminals places a turnon voltage between the gate and cathode of the SCR and causes the latter to discharge the triggering capacitor into the winding to fire a flash tube.
Inventors
- 👤 R Peacock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 03:15
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
229 words
Apparatus for discharging a charged capacitor into a load device comprising a first capacitor connected in series with a load device to a source of capacitor charging voltage, normally open switch means connected across the series combination of said first capacitoR and said load device and having first and second control connections between which the application of a control voltage causes said switch means to discharge said first capacitor into said load device, circuit means connected to said control connections and including first and second circuit points between which the completion of an electrical path causes said control voltage to be applied between said control connections, first and second terminals forming a first pair of terminals, third and fourth terminals forming a second pair of terminals, a second capacitor, conductors connecting said first and second terminals and said second capacitor in a first series circuit between said points to temporarily complete an electrical path between said points at the time of the completion of an electrical path between said first and second terminals, and conductors connecting said third and fourth terminals in a second series circuit between said points to complete an electrical path between said points at the time of the completion of an electrical path between said third and fourth terminals notwithstanding the concurrent presence of an already completed electrical path between said first and second terminals.
Claim 2
Dependent Claim
229 words
Apparatus for discharging a charged capacitor into a load device comprising a first capacitor connected in series with a load device to a source of capacitor charging voltage, normally open switch means connected across the series combination of said first capacitoR and said load device and having first and second control connections between which the application of a control voltage causes said switch means to discharge said first capacitor into said load device, circuit means connected to said control connections and including first and second circuit points between which the completion of an electrical path causes said control voltage to be applied between said control connections, first and second terminals forming a first pair of terminals, third and fourth terminals forming a second pair of terminals, a second capacitor, conductors connecting said first and second terminals and said second capacitor in a first series circuit between said points to temporarily complete an electrical path between said points at the time of the completion of an electrical path between said first and second terminals, and conductors connecting said third and fourth terminals in a second series circuit between said points to complete an electrical path between said points at the time of the completion of an electrical path between said third and fourth terminals notwithstanding the concurrent presence of an already completed electrical path between said first and second terminals.
Claim 3
Dependent Claim
40 words
Apparatus as specified in claim 1, wherein said first series circuit is connected to said source of voltage to cause said second capacitor to become charged upon the sustained completion of an electrical path between said first and second terminals.
Claim 4
Dependent Claim
33 words
Apparatus as specified in claim 2, wherein a resistor is connected directly across said second capacitor to discharge the latter in the absence of an electrical path between said first and second terminals.
Claim 5
Dependent Claim
78 words
Apparatus as specified in claim 1, wherein said source of voltage includes first, second, and third resistors connected in series across a storage capacitor, wherein said first capacitor and said load device are connected in a series circuit across the series combination of said second and third resistors, wherein said points are connected, respectively, to first and second conductors, and wherein said first and second conductors are connected in series with a fourth resistor across said third resistor.
Claim 6
Dependent Claim
16 words
Apparatus as specified in claim 4, wherein said control connections are connected across said fourth resistor.
Claim 7
Dependent Claim
76 words
Apparatus as specified in claim 1, wherein said first capacitor is the triggering capacitor of a photographic electronic flash apparatus having a hot shoe connector and a PC connector arranged for connection to camera shutter contacts, wherein said load device is the primary winding of a flash tube triggering transformer, wherein said first and second terminals are terminals of said hot shoe connector, and wherein said third and fourth terminals are terminals of said PC connector.
Claim 8
Dependent Claim
89 words
Apparatus as specified in claim 6, wherein said source of voltage includes first, second, and third resistors connected in series across a flash storage capacitor, wherein said triggering capacitor and said primary winding are connected in a series circuit across the series combination of said second and third resistors, wherein said points are connected, respectively, to first and second conductors, wherein said first and second conductors are connected in series with a fourth resistor across said third resistor, and wherein a third capacitor is connected across said third resistor.
Claim 9
Dependent Claim
51 words
Apparatus as specified in claim 7, wherein said switch means is a semiconductor device having anode, cathode, and gate electrodes, wherein said anode and said cathode are connected across the series combination of said second and third resistors, and wherein said gate and said cathode are connected across said fourth resistor.
Claim 10
Dependent Claim
36 words
Apparatus as specified in claim 7, wherein there is included a flash tube having electrodes connected across said storage capacitor, and wherein said triggering transformer includes a secondary winding arranged in firing relationship with said tube.
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) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |