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US4007399A Expired / Lapsed US ⏱️ 0.0 years remaining

Flashing circuitry

Assignee: Brady Corp
•
Filing: 1975-06-05
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Granted: 1977-02-08
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Expires: 1995-06-05
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Abstract

Abstract Electrical circuitry for delivering to a flashtube a series of flash-producing electrical pulses, the circuitry comprising energy circuitry means for repeatedly storing electrical energy and discharging the energy in the form of such pulses through the flashtube, each pulse producing a flash, each flash being grouped in a flash cycle synchronized with a cycle of an AC voltage source, the energy circuitry means comprising first and second capacitors connected by a switching element responsive to the difference between a first voltage at the junction between the first capacitor and the switching element and a second voltage on the second capacitor, the energy circuitry means stepping up the voltage discharged across the flashtube by the second capacitor, and firing circuitry means for receiving during each flash cycle a portion of the energy discharged by the energy circuitry means, to initiate each flash, the firing circuitry means being timed to initiate the flash, thereby reducing the second voltage upon discharge of the second capacitor, at a time during the period when the first voltage is below the value of the extinction voltage of the flashtube, so that the switching element remains off during the flash and the flashtube is thereby isolated from the first capacitor during the flash.

Inventors

  • 👤 Roby B. White

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 21:39
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/34

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 193 words
A circuit for operation in conjunction with a source of alternating current to deliver a pulse rich in ultraviolet light relative to the total energy of the pulse, comprising: a first, larger, capacitor; a second, smaller, capacitor; a flash tube having an extinction voltage; a third, trigger, capacitor; timing means; switching means; and a reference junction; said first capacitor being connected to be charged by said source during a first portion of a cycle thereof, and to discharge into said second and third capacitors; said second capacitor being connected to be charged also by said source during a second portion of a cycle thereof, and to discharge through said tube upon triggering thereof; said trigger capacitor being discharged by said timing means, to fire said flash tube; said reference junction having a voltage the instantaneous sum of line and that across said first capacitor; said switching means connecting said first and second capacitors when the voltage at said reference junction exceeds the voltage at said second capacitor; and said timing electronically reacting to discharge said trigger capacitor at a time when said reference junction has a voltage low relative to said extinction voltage.
Claim 2
Dependent Claim 193 words
A circuit for operation in conjunction with a source of alternating current to deliver a pulse rich in ultraviolet light relative to the total energy of the pulse, comprising: a first, larger, capacitor; a second, smaller, capacitor; a flash tube having an extinction voltage; a third, trigger, capacitor; timing means; switching means; and a reference junction; said first capacitor being connected to be charged by said source during a first portion of a cycle thereof, and to discharge into said second and third capacitors; said second capacitor being connected to be charged also by said source during a second portion of a cycle thereof, and to discharge through said tube upon triggering thereof; said trigger capacitor being discharged by said timing means, to fire said flash tube; said reference junction having a voltage the instantaneous sum of line and that across said first capacitor; said switching means connecting said first and second capacitors when the voltage at said reference junction exceeds the voltage at said second capacitor; and said timing electronically reacting to discharge said trigger capacitor at a time when said reference junction has a voltage low relative to said extinction voltage.
Claim 3
Dependent Claim 31 words
The circuit of claim 1 in which said timing means electronically reacts to discharge said trigger capacitor at a time when said reference junction has a voltage below said extinction voltage.
Claim 4
Dependent Claim 23 words
The circuit of claim 2 comprising also a resistor, said resistor with said third capacitor providing a time constant constituting said timing means.
Claim 5
Dependent Claim 16 words
The circuit of claim 3 in which said time constant is from 0.075 to 0.11 second.

References Cited (Backward Citations)

US3585444A Cited
US3767969A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1980-02-08 1980-08-09 1981-02-08 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-02-08 1984-08-09 1985-02-08 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-02-08 1988-08-09 1989-02-08 $7700.00 Window Closed / Lapsed

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