Ultrasound from compact florescent light bulbs

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SUMMARY

Compact fluorescent light bulbs (CFLs) are significant sources of ultrasonic noise, as confirmed by user experiences with the Marksman Ultrasonic Diagnostic Tool. This device detects ultrasonic frequencies, revealing that CFLs produce sounds at approximately 40kHz, which are perceptible even through plaster walls. The discussion raises concerns about the potential effects of this ultrasonic noise on pets, such as cats and dogs, who may be able to hear these frequencies, leading to discomfort akin to a constant ringing in their ears. There is currently a lack of scientific studies addressing the impact of ultrasonic sound from CFLs on humans.

PREREQUISITES
  • Understanding of ultrasonic frequencies and their measurement
  • Familiarity with the operation of compact fluorescent light bulbs
  • Knowledge of the Marksman Ultrasonic Diagnostic Tool and its applications
  • Basic concepts of sound propagation through different materials
NEXT STEPS
  • Research the effects of ultrasonic noise on pets, particularly cats and dogs
  • Investigate scientific studies on the health impacts of ultrasonic sound exposure in humans
  • Explore alternative lighting options that minimize ultrasonic emissions
  • Learn about the design and function of oscillators in compact fluorescent light bulbs
USEFUL FOR

This discussion is beneficial for homeowners, pet owners, lighting designers, and researchers interested in the effects of ultrasonic noise from compact fluorescent light bulbs.

Stephen Tashi
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Are compact florescent light bulbs know to be strong sources of ultrasounic noise?

I've been playing with a "Marksman Ultrasonic Diagnostic Tool", which presents ultrasounds as audible sound. It isn't a scientific instrument, so it doesn't give a decibel reading. It is used to detect leaks in AC systems, automobile engines etc.

I find that the primary sources of ultrasonic noise in my house (according to this device) are compact florescent light bulbs. Subjectively speaking, they are extremely loud compared to everything else I've tested such as whistling tea kettle, the refrigerator, computers, exercise machine etc. I can stand on one side of a plaster wall (genuine 1941 era plaster, not simply drywall) and , with the aid of the device, I can hear a lamp with a compact florescent light bulb on the other side. The wall seems to spread the sound over a large area. When I listen in the same room as the lamp, the source of the sound is more localized.

I suppose the device could inadvertently pick up EM waves and pesent them as sound, but its behavior in detecting florescent bulbs is consistent with the blubs being strong ultrasound sources. I wonder if cats and dogs can hear them.
 
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There is an oscilator in the compact bulbs that runs at about 40kHz, so I would think you are picking up correctly, the sound emitted from the compact bulb.

If your machine is sensitive enough to pick up this output, I would imagine so would a cat and dog. to them would it be like living with a constant ringing in their ears?
I have not come across any studies of the impact on humans to ultasonic sound from compact bulbs.
 

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