Assessing the close field non-ionizing emissions of PC-monitors

In recent years there has been an increase in the general concerns regarding the possible negative effects of non-ionizing electromagnetic emissions. A very common situation is determined by electric and magnetic emissions of computer monitors with which we work more than 8 hours a day. This display is located within small distance (around 50 cm) of the most sensitive organs of the human: the brain and eyes. That is the reason that the legal provisions of newly issued EU Directive 35 are completing some earlier rules, which were included in the so-called “TCO certification”. For instance, various synchronizing oscillators and switching power supply units are sources for low frequency electric and magnetic fields. It is no coincidence that the spectrum analyzer NF 5035, used by us for the measurements here reported, has preset from the design, a frequency band called TCO, a different band being dedicated to old CRT monitors and a third, to the currently all-over spread LCD monitors made in TFT technology. We have developed and applied a trustful methodology for measuring E&H field emissions of 4 types of monitors, representative for different generations. We have presented the situations when there were exceedances, issuing explanations and recommendations for control and reduction. Results and metrics were reported for cumulative, simultaneous exposure to many working displays.