US3878455A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit arrangement for measuring the filament emission current of a cathode-ray or x-ray tube
Assignee: US Philips Corp
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Filing: 1973-10-03
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Granted: 1975-04-15
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Expires: 1993-10-03
Abstract
Abstract The invention describes a simple circuit arrangement for measuring the emission currents of X-ray tubes with zero potential difference. The negative high voltage is applied to the cathode via a primary winding of a current transformer which via diodes is connected in parallel with the filament. The filament alternating voltage renders the diodes alternately conductive and non-conductive, so that the tube current flows in alternate directions through the current transformer. This enables an alternating-current signal which is proportional to the emission (direct) current to be derived from the secondary.
Inventors
- 👤 Rudolf Ochmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:02
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/26
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
170 words
Circuit arrangement for measuring the filament emission current of a cathode-ray tube, comprising: a first transformer having means for electrically connecting a secondary winding thereof across a filament of a cathode-ray tube and having means for electrically connecting a primary winding thereof to a suitable source of A.C. voltage for driving said filament with an alternating current; a second transformer having a primary winding with a center tap and a secondary winding; means for electrically connecting a source of suitably high D.C. voltage between an anode of said tube and said center tap of said primary winding of said second transformer; a pair of diodes having their respective anodes electrically connected to opposite ends of said secondary winding of said first transformer and having their respective cathodes electrically connected to opposite ends of said primary winding of said second transformer; and a resistance electrically connected between opposite ends of said secondary winding of said second transformer developing thereacross a voltage substantially proportional to the filament emission current of said tube.
Claim 2
Dependent Claim
170 words
Circuit arrangement for measuring the filament emission current of a cathode-ray tube, comprising: a first transformer having means for electrically connecting a secondary winding thereof across a filament of a cathode-ray tube and having means for electrically connecting a primary winding thereof to a suitable source of A.C. voltage for driving said filament with an alternating current; a second transformer having a primary winding with a center tap and a secondary winding; means for electrically connecting a source of suitably high D.C. voltage between an anode of said tube and said center tap of said primary winding of said second transformer; a pair of diodes having their respective anodes electrically connected to opposite ends of said secondary winding of said first transformer and having their respective cathodes electrically connected to opposite ends of said primary winding of said second transformer; and a resistance electrically connected between opposite ends of said secondary winding of said second transformer developing thereacross a voltage substantially proportional to the filament emission current of said tube.
Claim 3
Dependent Claim
32 words
Circuit arrangement as defined in claim 1 and further comprising an X-ray tube having an anode and having a filament across which is electrically connected said secondary winding of said first transformer.
Claim 4
Dependent Claim
325 words
Circuit arrangement for measuring the filament emission current of a cathode-ray tube, comprising: a cathode-ray tube having an anode and first and second filaments, one end of said first element being electrically connected to one end of said second filament; first and second transformers having respectively first and second secondary windings, one end of said first secondary winding being electrically connected to one end of said second secondary winding and being electrically connected to said one ends of said first and second filaments, the other end of said first secondary winding being electrically connected to the other end of said first filament, the other end of said second secondary winding being electrically connected to the other end of said second filament, said first and second transformers having respectively first and second primary windings and means for respectively connecting said first and second primary windings to a suitable source of A.C. voltage for driving said first and Second filaments respectively with an alternating current; a third transformer having a primary winding with a center tap and a secondary winding; means for electrically connecting a source of suitably high D.C. voltage between an anode of said tube and said center tap of said primary winding of said third transformer; a first diode having its anode electrically connected to said one ends of said first and second secondary windings of said first and second transformers and having its cathode electrically connected to one end of said primary winding of said third transformer; second and third diodes having their respective anodes electrically connected to said other ends of said first and second secondary windings respectively of said first and second transformers and having their cathodes electrically connected to the other end of said primary winding of said third transformer; and a resistance electrically connected between opposite ends of said secondary winding of said third transformer developing thereacross a voltage substantially proportional to the filament emission current of said tube.
Claim 5
Dependent Claim
325 words
Circuit arrangement for measuring the filament emission current of a cathode-ray tube, comprising: a cathode-ray tube having an anode and first and second filaments, one end of said first element being electrically connected to one end of said second filament; first and second transformers having respectively first and second secondary windings, one end of said first secondary winding being electrically connected to one end of said second secondary winding and being electrically connected to said one ends of said first and second filaments, the other end of said first secondary winding being electrically connected to the other end of said first filament, the other end of said second secondary winding being electrically connected to the other end of said second filament, said first and second transformers having respectively first and second primary windings and means for respectively connecting said first and second primary windings to a suitable source of A.C. voltage for driving said first and Second filaments respectively with an alternating current; a third transformer having a primary winding with a center tap and a secondary winding; means for electrically connecting a source of suitably high D.C. voltage between an anode of said tube and said center tap of said primary winding of said third transformer; a first diode having its anode electrically connected to said one ends of said first and second secondary windings of said first and second transformers and having its cathode electrically connected to one end of said primary winding of said third transformer; second and third diodes having their respective anodes electrically connected to said other ends of said first and second secondary windings respectively of said first and second transformers and having their cathodes electrically connected to the other end of said primary winding of said third transformer; and a resistance electrically connected between opposite ends of said secondary winding of said third transformer developing thereacross a voltage substantially proportional to the filament emission current of said tube.
Claim 6
Dependent Claim
16 words
Circuit arrangement as defined in claim 3 wherein said cathode-ray tube is a double-focus X-ray tube.
Claim 7
Dependent Claim
282 words
Circuit arrangement for measuring the filament emission current of a cathode-ray tube, comprising: a cathode-ray tube having an anode and first and second filaments, one end of said first filament being electrically connected to one end of said second filament; first and second transformers having respectively first and second secondary windings, one end of said first secondary winding being electrically connected to one end of said second secondary winding and being electrically connected to said one ends of said first and second filaments, the other end of said first secondary winding being electrically connected to the other end of said first filament, the other end of said second secondary winding being electrically connected to the other end of said second filament, said first and second transformers having respectively first and second primary windings and means for respectively connecting said first and second primary windings to a suitable source of A.C. voltage for driving said first and second filaments respectively with an alternating current; a third transformer having a primary winding with a center tap and a secondary winding; means for electrically connecting a source of suitably high D.C. voltage between an anode of said tube and said center tap of said primary winding of said third transformer; a pair of diodes having their respective anodes electrically connected to said other ends of said first and second secondary windings respectively of said first and second transformers and having their cathodes electrically connected to opposite ends of said primary winding of said third transformer; and a resistance electrically connected between opposite ends of said secondary winding of said third transformer developing thereacross a voltage substantially proportional to the filament emission current of said tube.
Claim 8
Dependent Claim
282 words
Circuit arrangement for measuring the filament emission current of a cathode-ray tube, comprising: a cathode-ray tube having an anode and first and second filaments, one end of said first filament being electrically connected to one end of said second filament; first and second transformers having respectively first and second secondary windings, one end of said first secondary winding being electrically connected to one end of said second secondary winding and being electrically connected to said one ends of said first and second filaments, the other end of said first secondary winding being electrically connected to the other end of said first filament, the other end of said second secondary winding being electrically connected to the other end of said second filament, said first and second transformers having respectively first and second primary windings and means for respectively connecting said first and second primary windings to a suitable source of A.C. voltage for driving said first and second filaments respectively with an alternating current; a third transformer having a primary winding with a center tap and a secondary winding; means for electrically connecting a source of suitably high D.C. voltage between an anode of said tube and said center tap of said primary winding of said third transformer; a pair of diodes having their respective anodes electrically connected to said other ends of said first and second secondary windings respectively of said first and second transformers and having their cathodes electrically connected to opposite ends of said primary winding of said third transformer; and a resistance electrically connected between opposite ends of said secondary winding of said third transformer developing thereacross a voltage substantially proportional to the filament emission current of said tube.
Claim 9
Dependent Claim
16 words
Circuit arrangement as defined in claim 5 wherein said cathode-ray tube is a double-focus X-ray tube.
References Cited (Backward Citations)
US2189894A
Cited
US3543030A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |