Magnetic field effects on computer monitors

B. Banfai, G. G. Karady, C. J. Kim, K. Maracas

Research output: Contribution to journalArticlepeer-review


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 jitter for the common 14-inch monitor. This value drops to around 7 mG for a 21-inch monitor.

Original languageEnglish (US)
Pages (from-to)60-61
Number of pages2
JournalIEEE Power Engineering Review
Issue number1
StatePublished - Dec 1 1999


  • CRT
  • EMI
  • Flicker
  • Jitter
  • Perceptibility
  • Refresh rate
  • Sensitivity
  • VDU

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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