Interesting observation about the high pitch LCD noise...

[none]

I'm sure most people here know what I'm talking about, it's a common question that no one seems to have the answer to lol... When the LCD brightness changes a lot (like when you minimize or maximize a window), a really high pitch noise is emitted from the LCD panel. Your AC adapter makes the same kind of noise if you listen to it up close, by the way.. Closest I've found to an answer, is it being emitted from the coil, which is just natural for high frequency electronics.

Anyway, interestingly enough, my ThinkPad isn't doing it since I got to Australia! Same machine and AC adapter. Voltage system is different though, I am pretty sure it's 220 here (as opposed to 110 in Canada). Just using a standard $5-ish RadioShack-ish adapter to make my US AC fit the Aussie sockets.

Any thoughts?

[Cavorite]

the inverter maybe? interesting...

[etherealtml]

Interesting indeed...

This is a little off topic, but does the toilet water really spin clockwise down under?

I think them Aussies use magic

[beeblebrox]

I think that the topic of the high pitching noise has already been solved many times in various forums.

Of course, it is the high frequency coils.
Ever wondered why TVs humm at high frequency (15 khz horizontal line frequency) or common transformers humm at low frequency (50Hz in Europe, 60 Hz in US).

open your notebook and you see a lot of coils...
Open a TV and you see even more coils.
The current in the wires induces electromagnetic force, so the wires in the coils vibrate with the frequency of the current.

[raabjerg]

Interesting, I'm on 220V here, but there is a little noise...

[edelrc]

Same here, if a put my ear over the keyboard and I minimize and maximize the IE browser window it does make a wizzz sound... I noticed this too... Very interesting indeed. I have 220V too.

[Thinker]

I know this is an old topic, but...

I noticed something interesting. I recently got a new AC adapter for my T23 (the old one went kaput), and I have noticed that when I am hooked to the AC power and I change the brightness setting, the high pitch changes following a pattern something like:

Brightness level...............Amount of whine (0-10)

0............................................1
1............................................1
2............................................3
3............................................2
4............................................5
5............................................2
6............................................9
7............................................3

I know there is a scientifical explanation for this, look at the alternating pattern. Does anyone know how the change in brightness level is achieved? Less voltage, I suppose. But, how is the change in the voltage itself achieved?

Very intriging matter.

To make things more suspenseful, I don't remember having any high pitch noise when I had the other AC adapter.

[edelrc]

Cute observation Thinker!
Indeed there is a pattern there... you almost can see the electronics switching on and off through that.