answersLogoWhite

0

There are many small Transformers and electronic oscillators in a CRT monitor which scan the electrons across the screen, blank them at the end of a line and return the beam to the left of the screen in order to start the scan again. These transformers have alternating currents flowing through them which make the ferrite cores 'chatter' at the same frequency. This frequency is about 18,000 cycles per second which makes this audible noise.

User Avatar

Wiki User

15y ago

What else can I help you with?