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Personal Computer and Laptops

Belongs to:
Computer and office devices
Synonyms:
Computer, Laptop, Laptop power supply, Pc, Personal computer
Description:

A computer is a device that can be programmed to carry out a set of arithmetic or logical operations automatically. The personal computer (abbr. PC) is used by a single person, unlike a mainframe computer at home or at work. A PC usually consists of a monitor, case, keyboard and mouse. The case normally contains a mainboard, a power supply, microprocessor (CPU) with a cooler, memory (RAM), a graphic card, a storage (HDD, SSD) and maybe disc drives for floppy discs, CDs or DVDs.
The laptop is a portable version of a PC and combines the computer with a monitor, mouse, and keyboard in one device. The power supply unit is commonly combined with the charging cable and thus not inside the laptop.
The sources of electric, magnetic and electromagnetic fields in a PC or laptop heavily depend on the used technology. As an example: A Hard Disc Drive (HDD) uses magnetic fields to store data and thus emits low frequency magnetic fields, Solid State Drives (SSD) to the contrary don't emit these fields because the storage technology is based on semiconductors. Further relevant sources of low-frequency or high-frequency fields are the power supply unit, the monitor or network modules for wireless communication like WLAN or Bluetooth. The listed measurement values in this article refer to fields emitted from the case of the computer, laptop or power supply unit. Monitors, WLAN and Bluetooth are separated in own articles.

Frequency ranges:
  • 50–60 Hz
Type of field:
electric, magnetic, and electromagnetic

Measurements (acc. to literature)

computer
Measurand Value Feature Remarks
magnetic flux density 0.01 µT (maximum, measured) - at a distance of 30 cm [1]
magnetic flux density 0.07–0.21 µT (measured) - at a distance of 50 cm [2]
magnetic flux density 0.12 µT (measured) - at a distance of 50 cm [3]
magnetic flux density 0.14 µT (mean, measured) - during use [4]
magnetic flux density 0.3 µT (maximum, measured) - at a distance of 61 cm [5]
magnetic flux density 0.5–30 µT (maximum) - at a distance of 3 cm [1]
magnetic flux density 1.5 µT (maximum, measured) - at a distance of 80 cm [6]
magnetic flux density 5 µT (maximum, measured) - at a distance of 40 cm [6]
magnetic flux density 10 µT (mean, measured) - at a distance of 15 cm [7]
magnetic flux density 50 µT (maximum) - in front of the device [6]
laptop
Measurand Value Feature Remarks
electric field strength 58 mV/m (maximum) - maximum value in the fetus [8]
electric field strength 80 V/m (measured) - at a distance of 1 m [9]
electric field strength 1.5 kV/m (measured) - in the vicinity of the device [9]
current density 1.9 mA/m² (maximum) - maximum value in the fetus [8]
magnetic flux density 0.08 µT (measured) - in the vicinity of the device [9]
magnetic flux density 3.8 µT (maximum) - maximum value at a frequency of 1 kHz [10]
magnetic flux density 5.27 µT (maximum) - maximum measured value under the laptop [8]
magnetic flux density 6 µT (maximum) - maximum value at a frequency of 18.0 kHz [10]
power density 4 mW/m² (maximum) - at a distance of 1 m [10]
power density 4 mW/m² (maximum) - maximum value at a distance of 1 m [11]
power density 22–4 mW/m² (maximum) - at a distance between 0.5 - 1 m [12]
power density 22 mW/m² (maximum) - maximum value at a distance of 0.5 m [11]
SAR 1.93 mW/kg (maximum) - as regards the whole body, assuming a transmitted power of 240 mW [13]
SAR 75 mW/kg (maximum) - maximum value averaged about 10 g tissue in the upper region of the left thigh [13]
power 17 mW (maximum) - maximum integrated radiated power [12]
power supply
Measurand Value Feature Remarks
electric field strength 1.34 kV/m (maximum, calculated) - at the surface of the device at 50 Hz [14]
magnetic flux density 29.5 µT (maximum) - maximum value at a frequency of 750 Hz [10]
magnetic flux density 30.2 µT (maximum) - maximum value while charging a battery [8]
magnetic flux density 1.59 mT (maximum, calculated) - at the surface of the device at 50 Hz [15]

References

  1. No authors listed (2018): [Radiation and radiation protection]
  2. Behrens T et al. (2004): Quantification of lifetime accumulated ELF-EMF exposure from household appliances in the context of a retrospective epidemiological case-control study.
  3. Preece AW et al. (1999): Assessment of Human Exposure to Magnetic Fields Produced by Domestic Appliances
  4. Mezei G et al. (2001): Household appliance use and residential exposure to 60-Hz magnetic fields.
  5. National Research Council (1997): Possible health effects of exposure to residential electric and magnetic fields.
  6. Farag AS et al. (1998): Electromagnetic fields in the home.
  7. Lacy-Hulbert A et al. (1998): Biological responses to electromagnetic fields.
  8. Zoppetti N et al. (2011): Evaluation and characterization of fetal exposures to low frequency magnetic fields generated by laptop computers.
  9. Ahmadi H et al. (2010): Electromagnetic fields near transmission lines - problems and solutions.
  10. Bellieni CV et al. (2012): Exposure to electromagnetic fields from laptop use of "laptop" computers.
  11. Khalid M et al. (2011): Exposure to radio frequency electromagnetic fields from wireless computer networks: Duty factors of Wi-Fi devices operating in schools.
  12. Swerdlow AJ et al. (2012): Health Effects from Radiofrequency Electromagnetic Fields - RCE 20.
  13. Zhou Y et al. (2008): SAR of Wireless Communication Terminals Operated near the Human Body Using the Example of PCMCIA Data Cards.
  14. Leitgeb N et al. (2008): Electric emissions from electrical appliances.
  15. Leitgeb N et al. (2008): Magnetic emission ranking of electrical appliances. A comprehensive market survey.