Magnetic field effects on CRT computer monitors

Author

Banfai, Balazs ; Karady, George G. ; Kim, Charles J. ; Maracas, Kate Brown

Author_Institution

Dept. of Electr. Eng., Arizona State Univ., Tempe, AZ, USA

Volume

15

Issue

1

fYear

2000

fDate

1/1/2000 12:00:00 AM

Firstpage

307

Lastpage

312

Abstract

This paper discusses the effect of external low frequency magnetic field interference on cathode ray tube (CRT) computer monitors. The paper describes a new test facility and presents a quantitative measuring method which has been developed to characterize the field effects. A total of 21 monitors from major manufacturers were tested. It was found that larger monitors are more sensitive and that the relationship between the magnitude of jitter and the magnetic flux density is linear and independent of the refresh rate and the frequency of the interfering magnetic field. The monitors are most sensitive to magnetic fields parallel to the screen. Monitor sensitivity is specified and presented for the tested monitors. A statistical survey was carried out to determine the human perceptibility level of jitter. It was found that 12 mG may cause detectable sitter for the common 14" monitor. This value drops to around 7 mG for a 21" monitor

Keywords

cathode-ray tube displays; computer displays; electromagnetic interference; jitter; magnetic field effects; magnetic flux; magnetic variables measurement; test facilities; 12 mG; 14 in; 21 in; 7 mG; CRT computer monitors; EMI; VDU; cathode ray tube; external low frequency magnetic field interference; flicker; human perceptibility level; jitter magnitude; magnetic field effects; magnetic flux density measurement; monitor sensitivity; quantitative measuring method; refresh rate; test facility; Cathode ray tubes; Computer displays; Frequency; Interference; Jitter; Magnetic field measurement; Magnetic fields; Manufacturing; Test facilities; Testing;

fLanguage

English

Journal_Title

Power Delivery, IEEE Transactions on

Publisher

ieee

ISSN

0885-8977

Type

jour

DOI

10.1109/61.847267

Filename

847267