Question about noise in LED product

[kingofwylietx]

I have a larger LED prototype light. Inside are approx 16 Lumileds and accompanying electronics (I don't know exactly what's in it, it's potted).

The question is: Why does it make a high-pitched sound while turned on? It's hard to describe, but I would say it's a high-pitched whine or hum. What would cause this, since it's all supposed to be solid state electronics?

 

[Norm]

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[LukeA]

Often the noise is a harmonic from an inductor.

 

[AnAppleSnail]

I have a larger LED prototype light. Inside are approx 16 Lumileds and accompanying electronics (I don't know exactly what's in it, it's potted).

The question is: Why does it make a high-pitched sound while turned on? It's hard to describe, but I would say it's a high-pitched whine or hum. What would cause this, since it's all supposed to be solid state electronics?

In short, the inductor is acting as a speaker coil and the flashlight body is the cone. This happens with individual lights, but some lines are worse than others.

 

[vaska]

In short, the inductor is acting as a speaker coil and the flashlight body is the cone. This happens with individual lights, but some lines are worse than others.

You'll be surprised, but ceramic capacitors are more likely to act like speakers due to piezo-effect.

 

[kingofwylietx]

Thank you. So it must be ceramic capacitors or the inductor. I think that I'll probably have to live with it, since neither of those sound like something I want to try to change out.