Leds and hearing

Has anyone done a study about leds affecting human hearing? Can running them influence the ear?

huh?
:thinking:


i would say running led affects my seeing

SAy , what?
Continuous exposure to high noise levels can damage hearing.
Maybe sleeping with a flashlight stuck in your ear could cause problems.

Student99, why don't you tell us more about your homework? Thank you.

I'm a old student(baby boomer) but have not stopped learning. I read this and was wondering what leds vibrate at.

"Ear cannot respond to all frequencies in an unbiased manner. Audible range of human being is commonly quoted as from 20 Hz to 20,000 Hz, which in fact will vary with age, health, past exposure to noises, and so forth. Ear also acts like a filter and will favour certain frequencies over the others. Ear is most sensitive to sounds at the range of 1,000 to 5,000 Hz, and particularly at about 4,000 Hz."

Autocorrect issue here?
edit: aha, never mind.
No surprise that we have a sweet spot in the same range as our voices.
I have a particular sensitivity to the range of a crying child. Like an ice pick in my ear.
Regarding LEDs, if we can't hear them then they are outside of the range or below the threshold of audible sound. They may still emit a sound, but it is doubtful it could have any affect on us as the body of an LED would not make a very efficient transducer.
IMHO, of course.

Erm, I'm not sure if LEDs vibrate enough when running to create audible noise. I can see PWM lights producing minute vibrations when the LED turns on and the die slightly expands due to heat. As for a constant current LED, maybe the noise would cause some vibrations.

Anyone have equipment to measure those minute vibrations?

Some drivers do produce audible sound when running. IIRC, this is due to the switching current causing some parts to vibrate.

High dBs cause hearing damage, not frequency (Hz).

I didn't know an LED could even make a sound. I know the PWM circuits can make noise, but it's so quiet I can't picture it doing any more harm than annoying.

I think some people might say that LEDs emit "vibrations" because they emit electromagnetic radiation...but I don't think that is an accurate statement. Why the concern?

I think you'd stand a better chance of incurring hearing damage from the sound of a mouse peeing on your pillow.

What if the mouse pees in your ear? heheheh

Student99 said:

Has anyone done a study about leds affecting human hearing? Can running them influence the ear?

Click to expand...

I'm not aware of any study. As far as influencing the ear, LEDs are just another semiconductor, nothing makes them more special than all the other diodes and transistors around us (except they are typically placed at the bottom of a parabolic reflector -- just a thought).

Student99 said:

[...]was wondering what leds vibrate at.[...]

Click to expand...

As bansuri noted, LEDs aren't really transducers.

Now technically, electrical current is accompanied by a magnetic field, and if the magnetic field is fluctuating or alternating direction there are forces that can cause mechanical movement, resonance, and sound, but the LED is probably one of the least components to be concerned with in this regard.

Slightly off topic, but the noise from filaments of household incan bulbs on dimmers drives me buggo. Switching to 3-way bulbs where the physical mounting of the filaments is different helped some.

LEDs do make vibrations, but at a frequency that is a million times(-ish) higher than what the OP mentions. The only audible noise from any of my LED torches is inductor whine, which is quite common. And a little annoying, actually....
Edit: and they are definitely transducers (electrical energy becomes electromagnetic radiation energy).

ICUDoc said:

LEDs do make vibrations, but at a frequency that is a million times(-ish) higher than what the OP mentions. The only audible noise from any of my LED torches is inductor whine, which is quite common. And a little annoying, actually....
Edit: and they are definitely transducers (electrical energy becomes electromagnetic radiation energy).

Click to expand...

Should've been more specific,"an LED would not make a very efficient electroacoustic transducer. "
It is, of course, a photoelectric transducer.

The LEDs on a graphic EQ do have an effect on my hearing!! :naughty:

ICUDoc said:

LEDs do make vibrations, but at a frequency that is a million times(-ish) higher than what the OP mentions. [...]

Click to expand...

Taken to an extreme, we end up with the concept of "temperature", where everything not at absolute zero is vibrating (or at least bouncing against each other) at the molecular (or atomic if you prefer) level.

ICUDoc said:

[...]Edit: and they are definitely transducers (electrical energy becomes electromagnetic radiation energy).

Click to expand...

I was thinking along the lines of piezoelectric, but you are right, that is not what I actually said.