The noise of a muted television

[jreelawg]

I have noticed that the television makes a very high pitched noise. You almost can't tell your hearing it until it is turned off. It is kind of like the ringing of the ear in a way. Then When I turn on the DTV box, the sound becomes a little louder and changes frequency.

Does anyone know what makes this noise? Is it some kind of electronic buzz? I also noticed that my computer, even while on power save mode, makes a similar annoying high pitch buzzing sound.

 

[Pumblechook]

Old style cathode ray tube TVs and monitors do whine at over 15 kHz (TVs). Usually only younger folks can hear so high.

A TV with no input can sound a little different to one with an input when the 15kHz locks into the incoming video. I would have thought the difference was small.

Another source would be switched mode powers supplies which are common in all sorts of equipment these days.