GB1535540A - Circuit for preventing the formation of a luminous spot on the screen of a television receiver upon switch-off - Google Patents

Circuit for preventing the formation of a luminous spot on the screen of a television receiver upon switch-off

Info

Publication number
GB1535540A
GB1535540A GB4164776A GB4164776A GB1535540A GB 1535540 A GB1535540 A GB 1535540A GB 4164776 A GB4164776 A GB 4164776A GB 4164776 A GB4164776 A GB 4164776A GB 1535540 A GB1535540 A GB 1535540A
Authority
GB
United Kingdom
Prior art keywords
switching
screen
circuit
oct
transistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB4164776A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Indesit Industria Elettrodomestici Italiana SpA
Original Assignee
Indesit Industria Elettrodomestici Italiana SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Indesit Industria Elettrodomestici Italiana SpA filed Critical Indesit Industria Elettrodomestici Italiana SpA
Publication of GB1535540A publication Critical patent/GB1535540A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H04N3/20—Prevention of damage to cathode-ray tubes in the event of failure of scanning

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Details Of Television Scanning (AREA)

Abstract

1535540 Cathode ray tube circuits INDESIT INDUSTRIA ELETTRODOMESTICI ITALIANA SpA 7 Oct 1976 [9 Oct 1975] 41647/76 Heading H4T A TV receiver circuit for preventing formation of a luminous spot on the screen on switching off comprises a unidirectional conduction device 3 (e.g. s/c diode) between the power supply line and the video amplifier stage to prevent discharge of the cathode immediately on switching off and a capacitor 6 of a value such as to conserve charge to maintain the tube cut off, for at least a time sufficient to allow the accelerator anode of the tube to discharge upon switching off. Also included are brightness control potentiometer 2, load resistor 4, and transistor 5. Transistor 5 base is biased from the supply section through terminal 13 and also receives the video signal. Circuit parameters are disclosed and operational features discussed. The c.r.t. accelerating anode of the c.r.t. 9 may have a 9 pF capacitance which causes undeflected electrons from the hot cathode to impede on the phosphor screen after the supply is switched off.
GB4164776A 1975-10-09 1976-10-07 Circuit for preventing the formation of a luminous spot on the screen of a television receiver upon switch-off Expired GB1535540A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT6951375A IT1055628B (en) 1975-10-09 1975-10-09 CIRCUIT TO PREVENT THE FORMATION OF THE LIGHT POINT IN A TELEVISION

Publications (1)

Publication Number Publication Date
GB1535540A true GB1535540A (en) 1978-12-13

Family

ID=11312297

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4164776A Expired GB1535540A (en) 1975-10-09 1976-10-07 Circuit for preventing the formation of a luminous spot on the screen of a television receiver upon switch-off

Country Status (3)

Country Link
DE (1) DE2645570C2 (en)
GB (1) GB1535540A (en)
IT (1) IT1055628B (en)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL113859C (en) * 1959-02-07
US3448328A (en) * 1966-05-30 1969-06-03 New Nippon Electric Co Cathode ray tube bright spot eliminating circuit
DE2235293C3 (en) * 1972-07-19 1982-09-09 Loewe Opta Gmbh, 8640 Kronach Circuit arrangement for suppressing the light spot on the screen of a picture tube in a television set

Also Published As

Publication number Publication date
IT1055628B (en) 1982-01-11
DE2645570C2 (en) 1985-06-05
DE2645570A1 (en) 1977-04-14

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Legal Events

Date Code Title Description
PS Patent sealed
PE20 Patent expired after termination of 20 years

Effective date: 19961006