High-pitched noise from tablet?

[MummyBtothree]

Our sons have got a tablet each and both makes a high pitched noise. Neither are faulty and ive googled the problem and it seems to be a common occurance. Forums mentioned something to do with the settings but I couldn't make head nor tail, anyone here able to expmain it for me in english? lol.

My iPhone does this if it is too close to the phone. (Land line). So i can only imagine it is to do with the frequency settings. Solution is to move away from noise source if they emit noise when next to each other (i mean the tablets not your sons lol).

Great thank you :)