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Clocks

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Synonyms:
Alarm clock, Analog clock, Digital clock, Radio clock
Description:

An alarm clock is a clock that is designed to make a sound, or some other signal, at a specific time to wake somebody or as a reminder. Alarm clocks are powered either by battery or connected to a socket with a cable. Radio clocks can play a radio broadcast or as the case may be a CD instead of preset sounds. Digital clocks have a display instead of an analogue clock face which can show more information and allows a weekday dependent wake-up time.

Due to the operation of the clock face with a motor or AC electronics for complex settings alternating electric and magnetic fields at higher frequency may be emitted.

Type of field:
electric and magnetic

Measurements (acc. to literature)

analog clock
Measurand Value Feature Remarks
magnetic flux density 0.252 µT (mean, measured) - geometric mean value in the frequency range from 54 Hz - 606 Hz at a distance of 50 cm [1]
magnetic flux density 0.3 µT (maximum, measured) - at a distance of 121.92 cm; examined frequency: 60 Hz [2]
magnetic flux density 0.5 µT (maximum, measured) - at a distance of 60.96 cm; examined frequency: 60 Hz [2]
magnetic flux density 0.608 µT (mean, measured) - geometric mean value in the frequency range from 54 Hz - 606 Hz at a distance of 25 cm [1]
magnetic flux density 0.7 µT (maximum, measured) - at a distance of 80 cm; examined frequency: 50 Hz resp. 60 Hz [3]
magnetic flux density 1.972 µT (mean, measured) - geometric mean value in the frequency range from 54 Hz - 606 Hz at a distance of 10 cm [1]
magnetic flux density 2 µT (maximum, measured) - at a distance of 40 cm; examined frequency: 50 Hz resp. 60 Hz [3]
magnetic flux density 3 µT (maximum, measured) - at a distance of 30.48 cm; examined frequency: 60 Hz [2]
magnetic flux density 6 µT (maximum, measured) - at the surface of the device; examined frequency: 50 Hz resp. 60 Hz [3]
magnetic flux density 52.5 µT (mean, measured) - geometric mean value in the frequency range from 0 Hz - 6 Hz at a distance of 50 cm [1]
magnetic flux density 55.5 µT (mean, measured) - geometric mean value in the frequency range from 0 Hz - 6 Hz at a distance of 10 cm; at a distance of 25 cm, the same geometric mean value has occured [1]
digital clock
Measurand Value Feature Remarks
magnetic flux density 0.1 µT (measured) - at a distance of 30.48 cm [4]
magnetic flux density 0.1 µT (mean, measured) - at a distance of 30.48 cm; examined frequency: 60 Hz [2]
magnetic flux density 0.1 µT (maximum, measured) - at a distance of 1.22 m; examined frequency: 60 Hz [2]
magnetic flux density 0.2 µT (maximum, measured) - at a distance of 60.96 cm; examined frequency: 60 Hz [2]
magnetic flux density 0.4 µT (maximum) - at a distance of 15 cm [4]
magnetic flux density 0.8 µT (maximum, measured) - at a distance of 30.48 cm; examined frequency: 60 Hz [2]
clock (no further specification)
Measurand Value Feature Remarks
magnetic flux density 0.01 µT (mean, measured) - average value of 6 devices at a distance of 1 m; measurement bandwidth: 40 - 800 Hz [5]
magnetic flux density 0.04 µT (mean, measured) - average value of 6 devices at a distance of 50 cm; measurement bandwidth: 40 - 800 Hz [5]
magnetic flux density 0.07 µT - near the device; examined frequency: 120 Hz (first hamonic) [1]
magnetic flux density 0.086 µT (mean, measured) - geomertic mean value in the frequency range from 54 Hz - 606 Hz at a distance of 50 cm [1]
magnetic flux density 0.1 µT (maximum, measured) - near the device; examined frequency: 60 Hz [1]
magnetic flux density 0.151 µT (mean, measured) - geometric mean value in the frequency range from 54 Hz - 606 Hz at a distance of 25 cm [1]
magnetic flux density 0.2 µT (measured) - at a distance of 60.96 cm [4]
magnetic flux density 0.397 µT (mean, measured) - geometric mean value in the frequency range from 54 Hz - 606 Hz at a distance of 10 cm [1]
magnetic flux density 5 µT (mean, measured) - average value of 6 devices at a distance of 5 cm; measurement bandwidth: 40 - 800 Hz [5]
magnetic flux density 20 µT (measured) - at a distance of 30.84 cm [4]
magnetic flux density 52.5 µT (mean, measured) - geometric mean in the frequency range from 0 Hz - 6 Hz at a distance of 25 cm [1]
magnetic flux density 54.2 µT (mean, measured) - geometric mean value in the frequency range from 0 Hz - 6 Hz at a distance of 50 Hz [1]
magnetic flux density 60.7 µT (mean, measured) - geometric mean value in the frequency range from 0 Hz - 6 Hz at a distance of 10 cm [1]
alarm clock
Measurand Value Feature Remarks
magnetic flux density 0.01–0.02 µT (maximum) - at a distance of 1 m [6]
magnetic flux density 0.1–1 µT (maximum) - at a distance of 30 cm [6]
magnetic flux density 3–60 µT (maximum) - at a distance of 3 cm [6]
magnetic flux density 0.06 µT (mean, measured) - average of 9 devices at a distance of 50 cm; measurement bandwidth: 0 - 3 kHz [8]
magnetic flux density 0.5 µT - at a distance of 20 cm; measurement bandwidth: 0 - 3 kHz [8]
magnetic flux density 0.74 µT (maximum) - at a distance of 40 cm [9]
magnetic flux density 0.9 µT (maximum, measured) - maximum value at a distance of 80 cm; this measurement value also applies to digital clocks at the same distance; examined frequency: 50 Hz resp. 60 Hz [3]
magnetic flux density 1.02 µT (mean, measured) - average of 9 devices at a distance of 10 cm; measurement bandwidth: 0 - 3 kHz [8]
magnetic flux density 2.4 µT - at the surface; measurement bandwidth: 0 - 3 kHz [8]
magnetic flux density 3 µT (maximum) - maximum value at a distance of 40 cm; this measurement value also applies to digital clocks at the same distance; examined frequency: 50 Hz resp. 60 Hz [3]
magnetic flux density 6 µT (maximum) - maximum value directly in front of the device; this measurement value also applies to digital clocks at the same distance; examined frequency: 50 Hz resp. 60 Hz [3]
radio clock
Measurand Value Feature Remarks
magnetic flux density 0.01 µT (mean, measured) - average value of 32 devices at a distance of 1 m; measurement bandwidth: 40 - 800 Hz [5]
magnetic flux density 0.05 µT (mean, measured) - average value of 32 devices at a distance of 50 cm; measurement bandwidth: 40 - 800 Hz [5]
magnetic flux density 0.2–2 µT (maximum) - at a distance of 30 cm [7]
magnetic flux density 2.34 µT (mean, measured) - average value of 32 devices at a distance of 5 cm; measurement bandwidth: 40 - 800 Hz [5]

References

  1. Kaune WT et al. (2002): Magnetic fields produced by hand held hair dryers, stereo headsets, home sewing machines, and electric clocks.
  2. EPA (1992): EMF in your Environment- Magnetic Field Measurements of Everyday Electrical Devices.
  3. Farag AS et al. (1998): Electromagnetic fields in the home.
  4. Lacy-Hulbert A et al. (1998): Biological responses to electromagnetic fields.
  5. Preece AW et al. (1997): Magnetic fields from domestic appliances in the UK.
  6. IEH et al. (2012): [BMU study: Ecological effects of 380-kV-ground wires and HGÜ-ground wires. (Report of the working group Engineering / Economics) Volume 4.3]
  7. Neitzke HP et al. (2006): [EMF manual. Electromagnetic fields: sources, risks, protection].
  8. Ainsbury EA et al. (2005): An investigation into the vector ellipticity of extremely low frequency magnetic fields from appliances in UK homes.
  9. 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.