The question is purely academic, as normal sound dampening solutions seem to work fine.
I understand how electronic circuits make sound as per this answer:
My question is, a cheap 2 AA battery (3 volt) inverter makes as much sound as the cathode ray moving on an old tube television.
What part in it is "moving" that creates that much noise?
How much amplitude is created? and how? The sound can be heard from across quiet room.
Normally high frequency sounds are very easy to locate the direction. However, in this instance, why does the sound appear directionless, like a low frequency sound?
Is it possible to invert DC to AC without audible noise? Or is this a mechanical feature?