US2188290A - Protective device in television receivers - Google Patents

Protective device in television receivers Download PDF

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Publication number
US2188290A
US2188290A US105626A US10562636A US2188290A US 2188290 A US2188290 A US 2188290A US 105626 A US105626 A US 105626A US 10562636 A US10562636 A US 10562636A US 2188290 A US2188290 A US 2188290A
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Prior art keywords
cathode
anode
tube
protective device
television receivers
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Expired - Lifetime
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US105626A
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Ardenne Manfred Von
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Individual
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Priority to US697739A priority Critical patent/US2096987A/en
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Priority to US105626A priority patent/US2188290A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
    • H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
    • H04N3/18—Generation of supply voltages, in combination with electron beam deflecting

Definitions

  • the invention relates to the particular embodiment of mains apparatus for delaying the initiation of the anode potential in Braun tubes.
  • the use of indirectly heated cathodes in tube apparatus, in Braun tubes acts detrimentally on the life thereof, owing to the long time required for heating the cathode, if the full anode potential becomes efiective before the cathode has attained a sufficiently high temperature.
  • Now when using normal mains apparatus the anode potential acquires its full voltage almost instantaneously, whereas the temperature of the cathode, and together therewith the emission, increases only very slowly, and frequently does not attain a sufiiciently high value until after an elapse of several minutes.
  • Said cathode fall is particularly dangerous because of the relatively small surface of the highly emissive material.
  • I is the mains transformer, 2, 7 and I2 cathode filament, Wehnelt cylinder and anode of a Braun tube, 5 a rectifier tube having a cathode filament 4 and anode 8.
  • the transformer is provided with three secondary windings of which 6 produces the high alternating tension for the rectifier whilst the two other secondary windings are connected to the heater of the Braun tube via an adjustable re- 1936, Serial No. 105,626.
  • the anode tube 5 is connected tothe Wehnelt cylinder 1 and via a biassing resistance 9 to the cathode 2.
  • the condensers I 0 and II serve for smoothing.
  • the device l5 may consist, in a well known manner, of a thermic relay operated, for example, by the heating current of the cathode of the Braun tube and actuates a switch closing the heating circuit of the cathode 4 after a certain ime.
  • a mains supply and a 9 Braun tube having cathode filament, Wehnelt cylinder and anode said mains supply comprising a transformer having a primary winding connected to the mains and three secondary windings, a rectifier tube producing the direct current high tension for the anode and the Wehnelt cylinder of said Braun tube, and smoothing means, one of said secondary windings connected on the one side to the cathode of said rectifier and on the other side to the anode of said Braun tube, the second to the filament of said Braun tube, the third to the filament of said rectifier tube, in the last circuit a thermostatic switch closing the circuit after a certain time interval the anode of said rectifier being connected directly to said Wehnelt cylinder and via a resistance to said cathode of the Braun tube, said smoothing means comprising at least condensers connected on the one hand across the Wehnelt cylinder and the anode and on the other hand across the Wehnelt cylinder and the cathode

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Electron Sources, Ion Sources (AREA)

Description

Jan. 23, 1940. M, VON ARDENNE 2,188,290
PROTECTIVE DEVICE IN TELEVISION RECEIVERS Original Filed Nov. 13, 1933 Jaye/Mar? Patented Jan. 23, 1940 UNITED STATES PATENT OFFICE PROTECTIVE DEVICE 1N TELEVISION RECEIVERS Manfred von Ardenne, Berlin, Germany 14, November 15, 1932 1 Claim.
The invention relates to the particular embodiment of mains apparatus for delaying the initiation of the anode potential in Braun tubes. The use of indirectly heated cathodes in tube apparatus, in Braun tubes, acts detrimentally on the life thereof, owing to the long time required for heating the cathode, if the full anode potential becomes efiective before the cathode has attained a sufficiently high temperature. Now when using normal mains apparatus the anode potential acquires its full voltage almost instantaneously, whereas the temperature of the cathode, and together therewith the emission, increases only very slowly, and frequently does not attain a sufiiciently high value until after an elapse of several minutes.
This application is a division of application Serial No. 697,739, filed November 13, 1933, Patent No. 2,096,987, dated October 26, 1937.
In the interval before the complete emission takes place there is produced a particularly strong cathode fall, which leads to a vigorous bombardment of ions and to a greatly shortened life and a deformation of the cathode, similar to the manner in which, as well known, under-heated cathodes are subject to premature wear or damage in tube apparatus. If the heating period amounts, for example, to 1 minute for an indirectly heated cathode, the dangerous state with the bombardment of ions commences, as experiments have shown, after approximately 10 seconds.
Said cathode fall is particularly dangerous because of the relatively small surface of the highly emissive material.
According to the invention, these disadvantages are overcome by special measures preventing the anode D. C. potential from becoming its full value before the cathode has reached a sufiiciently high temperature and accordingly an adequate emission.
The present invention will be best understood by the accompanying drawing, in which I is the mains transformer, 2, 7 and I2 cathode filament, Wehnelt cylinder and anode of a Braun tube, 5 a rectifier tube having a cathode filament 4 and anode 8. The transformer is provided with three secondary windings of which 6 produces the high alternating tension for the rectifier whilst the two other secondary windings are connected to the heater of the Braun tube via an adjustable re- 1936, Serial No. 105,626. In Germany sistance 3, respectively to the filament 4 of the rectifier tube 5 via a thermionic time lag device 15. The anode tube 5 is connected tothe Wehnelt cylinder 1 and via a biassing resistance 9 to the cathode 2. The condensers I 0 and II serve for smoothing.
The use of such a time switch device is well known for other purposes for example for limiting the anode current as shown by the British patent specification No. 372,799.
The device l5 may consist, in a well known manner, of a thermic relay operated, for example, by the heating current of the cathode of the Braun tube and actuates a switch closing the heating circuit of the cathode 4 after a certain ime.
The possible form of embodiment referred to may undergo numerous modifications within the meaning of the invention. It is essential that in each case a thermic time lag device is provided in order to ensure that the anode potential does not reach its full value until after the elapse of a certain time which is necessary to raise the indirectly heated cathode to a sufiiciently high temperature.
I claim:
In a television receiver a mains supply and a 9 Braun tube having cathode filament, Wehnelt cylinder and anode, said mains supply comprising a transformer having a primary winding connected to the mains and three secondary windings, a rectifier tube producing the direct current high tension for the anode and the Wehnelt cylinder of said Braun tube, and smoothing means, one of said secondary windings connected on the one side to the cathode of said rectifier and on the other side to the anode of said Braun tube, the second to the filament of said Braun tube, the third to the filament of said rectifier tube, in the last circuit a thermostatic switch closing the circuit after a certain time interval the anode of said rectifier being connected directly to said Wehnelt cylinder and via a resistance to said cathode of the Braun tube, said smoothing means comprising at least condensers connected on the one hand across the Wehnelt cylinder and the anode and on the other hand across the Wehnelt cylinder and the cathode of the Braun tube.
MANFRED VON ARDENNE.
US105626A 1932-11-15 1936-10-14 Protective device in television receivers Expired - Lifetime US2188290A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US697739A US2096987A (en) 1932-11-15 1933-11-13 System for energizing a cathode ray tube
US105626A US2188290A (en) 1932-11-15 1936-10-14 Protective device in television receivers

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE2096987X 1932-11-15
US697739A US2096987A (en) 1932-11-15 1933-11-13 System for energizing a cathode ray tube
US105626A US2188290A (en) 1932-11-15 1936-10-14 Protective device in television receivers

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US2188290A true US2188290A (en) 1940-01-23

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US697739A Expired - Lifetime US2096987A (en) 1932-11-15 1933-11-13 System for energizing a cathode ray tube
US105626A Expired - Lifetime US2188290A (en) 1932-11-15 1936-10-14 Protective device in television receivers

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US697739A Expired - Lifetime US2096987A (en) 1932-11-15 1933-11-13 System for energizing a cathode ray tube

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3086142A (en) * 1957-11-12 1963-04-16 Burke John Donald Final anode supply systems for cathode-ray tubes

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE623370A (en) * 1961-10-09

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3086142A (en) * 1957-11-12 1963-04-16 Burke John Donald Final anode supply systems for cathode-ray tubes

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US2096987A (en) 1937-10-26

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