File this under knowledge learned in college and since lost.
What is the frequency of that high pitched sound eminating from CRT based televisions? The tv need only be on, not necessarily tuned to any station. Many people can't hear it, but I can, and I've often wondered what frequency that is.
Anybody know? I've googled and come up empty.
19KHZ if I remembr correctly....
I have mentioned hearing the same noise to a few people and they looked at me like I was nuts.
Actually, it's 15,735 Hz, the horizontal frequency of NTSC. The flyback transformer is the culprit.
EDIT: Incidentally you can get this figure by multiplying the number of lines of resolution (525) by the frames per second (29.97).
Peter, you win the "nerd-for-the-day" award.
Thank you.
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Winner of the nerd-of-the-day award, October 26, 2005
I've always heard it. very annoying...at least my hearing is still good. can't say the same for my memory.
In reply to:
The flyback transformer is the culprit.
Further to this, there are also some inductors on the main board with ferrite cores encapsulated in plastic. The ferrite core develops a chip and the voltage running through the coil causes the ferrite chip to vibrate within the plastic casing at a high frequency. This frequency can vary from set to set (when it fails) and is extremely annoying. It usually occurs at a frequency lower than that of the flyback and is more audible (drives me nuts).
Nice try, Bruce, but you cannot steal Peter's award from him so soon.
Thanks guys...and yes Peter, you get the big dork award this week.
You guys are all impressively nerdy.
In reply to:
Nice try, Bruce, but you cannot steal Peter's award from him so soon.
What!? No consolation prize? Runner up? Gold star?
OK...you can have a gold star.
Peter,
I knew it was about 16 kHz but I did not know you could calculate that from the number of NTSC scanning lines multiplied by the frame-per-second rate. Congrats!
Regards,
I didn't realize it, myself, until the other day when I looked at the frequency and decided there had to be a simple reason for it being what it is.
In reply to:
What!? No consolation prize? Runner up? Gold star?
How 'bout a nice gold calculator?
>>Peter, you win the "nerd-for-the-day" award.
I don't know whether to be PO'd that Peter beat me to it or relieved that I didn't win the prize
Oh man, Craig, that looks sweet!
Don't tell me that's yours?
Whoa! It doubles as a business card holder. Bonus!
