Is it possible for high-frequency circuits to make audible noise?

[CTho9305]

Is it possible for circuits operating upwards of 14 MHz to make audible noise (sound)? There are no moving parts... just caps, inductors, some resistors, and ICs.

 

[Peter]

Well, there might be parts that move although they shouldn't. Prime suspect: Inductor coils.

 

[zephyrprime]

Yeah sure. But it wouldn't be the high freq that does it. It'd be the low frequencies. The freqs within human hearing. An inductor coil can produce a magnetic field that causes a nearby metal sheet or something like that to vibrate. This is what causes some fluorescent lights to hum.

 

[CTho9305]

Would this lead to earlier failure?

 

[Sukhoi]

Bah, just blurt out that your motherboard is humming and you're freaked out.

 

[CTho9305]

Originally posted by: Sukhoi
Bah, just blurt out that your motherboard is humming and you're freaked out.

I'm trying to avoid asking a tech support question . By the way, I have now swapped out EVERYTHING including the CPU and the noise remains .

 

[Akira13]

My Microsoft Wireless Optical Mouse used to squeak (like a real mouse) because of some design flaw. The squeaking stopped as the batteries died. MS tech support said it was some sort of capacitor problem.

 

[Hayabusa Rider]

I had a bad cap on a power supply do that.

 

[Sukhoi]

Originally posted by: CTho9305

Originally posted by: Sukhoi
Bah, just blurt out that your motherboard is humming and you're freaked out.

I'm trying to avoid asking a tech support question . By the way, I have now swapped out EVERYTHING including the CPU and the noise remains .

Hmm, sneaky tactic there.

 

[davesaudio]

two frequencies that are very close can beat against each other and produce a third new low frequency

 

[BillGates]

My wireless router started making a high pitched noise internally when it stopped working.

 

[ethebubbeth]

heh, my cable modem and wired router both make extremely annoying high pitched whines =/

 

[maluckey]

Yes and no. They can make frequencies audible to human hearing (Low-mid), and no, it's not generally harmfull, and mostly a nuisance. The PCMs on my two cars do it, and have done so for nine years with no incidents. I also had caps in my home power amplifiers do it at power-down, and drove me nuts.

 

[PowerMacG5]

Originally posted by: Akira13
My Microsoft Wireless Optical Mouse used to squeak (like a real mouse) because of some design flaw. The squeaking stopped as the batteries died. MS tech support said it was some sort of capacitor problem.

My former one did that too. I'm sensitive to noise, so it bothered me until the batteries were literally dead and the mouse not functioning anymore. I returned it and got a replacement. It seemed they fixed the problem in the newer ones because when I replaced it a few months ago it never made the noise again. I have now moved onto the Bluetooth desktop and it never makes a noise (I can still hear it though when I put my head near the mouse).

 

[Cadaver]

Medical MR imagers make a lot of noise as their coils alter the magnetic field gradient. There's no moving parts there...

 

[Mark R]

Well, the gradient coils do move (albeit very slightly) because of the enormous forces generated by the interaction of the static and dynamic fields - it's difficult to hold the wires still, as there could potentially be several hundred lbs of force. It's this movement that generates the noise. Simply altering the magnetic field doesn't produce the noise - it's the forces on the wires.

The same thing explains the noise that switching power supplies make - the ripple current in the magnetic components constantly varies, resulting in oscillating magnetic forces in the inductors, which can cause loosly wound coils to vibrate. In the case of PC VRMs, an audible vibration is likely to come from a subharmonic oscillation (maybe mechanical) as the operating frequency is typically in the MHz range.

 

[Passions]

haha this thread owns.