US3862422A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of operation of photoconductive varistor
Assignee: General Electric Co
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Filing: 1972-12-29
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Granted: 1975-01-21
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Expires: 1992-12-29
Abstract
Abstract A photoconductive polycrystalline varistor comprising a sintered body of zinc oxide and a minor constituent consisting of other metal oxides or halides has a pair of electrodes on one major face thereof. The electrical resistance between the electrodes is a non-linear function of the electrical potential applied between the electrodes and is additionally a function of the intensity of illumination of the interelectrode gap. The photoconductor sensitivity is further a function of the voltage across the electrodes.
Inventors
- 👤 Herbert R Philipp
- 👤 Lionel M Levinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:27
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
116 words
A method of operating a photoconductive varistor having a first pair of electrodes disposed on a face of a body of polycrystalline varistor material, said electrodes having a gap therebetween, said method comprising the steps of: applyling an electrical potential between said electrodes, said potential being preselected to determine the sensitivity and magnitude of photocurrent of said photoconductive varistor; positioning said photoconductive varistor to receive energy to be detected; and receiving, in a utilization device, an electrical current flowing between said electrodes across said gap, said current being proportional to said potential and to the intensity of said energy; the ratio of said photocurrent plus dark current to dark current being inversely proportional to said potential.
Claim 2
Independent Claim
116 words
A method of operating a photoconductive varistor having a first pair of electrodes disposed on a face of a body of polycrystalline varistor material, said electrodes having a gap therebetween, said method comprising the steps of: applyling an electrical potential between said electrodes, said potential being preselected to determine the sensitivity and magnitude of photocurrent of said photoconductive varistor; positioning said photoconductive varistor to receive energy to be detected; and receiving, in a utilization device, an electrical current flowing between said electrodes across said gap, said current being proportional to said potential and to the intensity of said energy; the ratio of said photocurrent plus dark current to dark current being inversely proportional to said potential.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein maximum sensitivity is desired and said electrical potential is preselected at a low voltage level.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein a large photocurrent magnitude is desired and said electrical potential is preselected at a high voltage level.
Claim 5
Dependent Claim
44 words
The method of claim 1 wherein a dark current flows between said electrodes in the absence of energy received by said photoconductive varistor and further comprising the step of: eliminating said dark current from said electrical current proportional to said intensity of said energy.
Claim 6
Dependent Claim
33 words
The method of claim 4 wherein said eliminating step comprises: bucking, in a bridge circuit, said current flowing between said first pair of electrodes, against a constant current equal to said dark current.
Claim 7
Dependent Claim
80 words
The method of claim 4 wherein a second pair of electrodes is disposed on a face of said body, said second pair of electrodes having a second gap therebetween, said second gap being shielded from radiated energy so that only dark current flows between said second pair of electrodes and wherein said eliminating step comprises: bucking, in a bridge circuit, said current flowing between said first pair of electrodes against said dark current flowing between said second pair of electrodes.
Claim 8
Dependent Claim
35 words
The method of claim 4 wherein said eliminating step includes chopping said energy to be detected and said receiving step includes rejecting a D.C. component from said current proportional to said intensity of said energy.
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) | 1978-01-20 | 1978-07-22 | 1979-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-20 | 1982-07-22 | 1983-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-20 | 1986-07-22 | 1987-01-21 | $7700.00 | Window Closed / Lapsed |