The study and implementation of a microprocessor-controlled demagnetizer

Author

Juan, Chang-Jung ; Kuo, Ching-Chih ; Wen, Chung-Yao

Author_Institution

Dept. of Electron. Eng., Hwa Hsia Coll. of Technol. & Commerce, Taipei, Taiwan

Volume

44

Issue

2

fYear

1998

fDate

5/1/1998 12:00:00 AM

Firstpage

405

Lastpage

412

Abstract

A display monitor is constructed using a cathode ray tube (CRT), a deflection yoke (DY), and a control circuit. It is known that the shadow mask inside a color CRT can be magnetized by the geomagnetic field or other causes so as to bias the electron beam path, deviate its landing spot, and degrade the screen color purity. This paper presents an electronic demagnetizer to degauss the shadow mask and therefore improve the screen color purity. This electronic demagnetizer includes an over-current protector, a degaussing-time adjuster, and a degaussing detector to determine whether the degaussing operation is normal or not. After experiments and trials in the factory, the degaussing method presented in this paper is proved to be more effective and stable than the commercialized products off the shelf

Keywords

cathode-ray tube displays; computer displays; computerised control; computerised instrumentation; demagnetisation; electronic engineering computing; microcomputer applications; cathode ray tube; color CRT; control circuit; deflection yoke; degaussing; degaussing detector; degaussing-time adjuster; display monitor; electron beam path; electronic demagnetizer; geomagnetic field; landing spot; microprocessor-controlled demagnetizer; over-current protector; screen color purity; shadow mask; Cathode ray tubes; Circuits; Degradation; Demagnetization; Detectors; Displays; Electron beams; Geomagnetism; Monitoring; Protection;

fLanguage

English

Journal_Title

Consumer Electronics, IEEE Transactions on

Publisher

ieee

ISSN

0098-3063

Type

jour

DOI

10.1109/30.681957

Filename

681957