Aural sensitivity to electronics
Aural sensitivity to electronics is really just part of having Auditory Hypersensitivity that is able to easily hear the low level 'hums', 'whistles' and 'hisses' that certain kinds of electronic circuits and components give off, which most people with normal hearing don't perceive as noticeable. These are electro-mechanical manifestations that occur within the audio spectrum (nominally 20Hz to 20KHz) due to tiny physical movements within components caused by varying voltage and current stress that the part is subject to within the circuit application, not to be confused with radio-frequency emissions, such as Wi-Fi and 5G, that some people claim make them feel unwell.
It is generally going to be items that are higher voltage-stress applications, such as power supplies, lighting drivers, TVs and monitors among other things, that may be particularly noticeable. Things that are very low power and run on a battery, such as a digital thermometer, have very little voltage stress on their components and are essentially silent in operation.
Some electronic products, such as computers, have more obvious noise sources such as cooling fans and hard drives (non-SSD type) which are motor driven, and therefore also class as electro-mechanically generated noise, but these are loud enough to be readily audible by people with normal hearing. For people with hypersensitive hearing, this kind of obvious noise may be much louder sounding than it is to those with normal hearing.
With the proliferation of electrical and electronic products that are part of modern life now, it can be hard to find anywhere in the home that is completely free of it all.
Workarounds
For advice on workarounds for Auditory Hypersensitivity, see the Auditory perception page.