Low electronic whistle sound from wall keypads in silent room

[Kreart 0]

Hello,

I have two wall keypads connected to my Yubii Home system.

In a completely silent room, when the keypad is powered, I can hear a very light high-pitched whistle / electronic hiss coming directly from the keypad.

It disappears when power is removed.

Questions:

1. Is this normal behavior?
2. Could it be LED backlight / internal converter coil whine?
3. Can brightness or LED settings reduce it?
4. Could power supply quality cause this?

Thank you.

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[Tim__ 126]

Probably a question for the manufacturer. Are the wallpads Fibaro branded?

[m.roszak 763]

No, they are not.
And in cheap electronics its typical that coils are noisy.