Re: General monitor question: screen resolution relay?

From: Alex Bird (alex_at_redbeastie.fsnet.co.uk)
Date: 08/27/04 

Date: 27 Aug 2004 12:19:49 -0700

"Asimov" <Asimov@-removethis-bbs.juxtaposition.dynip.com> wrote in message news:<MSGID_1=3a167=2f133.0_412f3d58@fidonet.org>...
> "Jim Adney" bravely wrote to "All" (26 Aug 04 21:10:10)
> --- on the heady topic of "General monitor question: screen resolution relay?"
>
> JA> From: Jim Adney <jadney@vwtype3.org>
>
> JA> In all the VGA & SVGA monitors I've used there seems to be a relay
> JA> that clicks when the screen rate changes. I'm guessing that this is
> JA> just a relay that switches in/out some C to change a timing circuit
> JA> for the H or V sweep.
>

> I think the click results from the change in scan frequency
> rearranging the surface static charge around the deflection coil. Kind
> of like the snap of a whip. The change in frequency alters the raster
> size, so a correction must be made by adding/removing different
> impedances to the deflection system, usually at the output. A relay
> could be used but it is cheaper and much more reliable to use
> transistors or powerfets. Which explains why you can't even find a
> relay!

I think there's two separate sounds here. I can recall monitors
making either or both of these sounds. The second is more subtle
usually.

Alex

Relevant Pages

  • Re: General monitor question: screen resolution relay?
    ... > that clicks when the screen rate changes. ... > just a relay that switches in/out some C to change a timing circuit ... It's in the horizontal circuit, that's the only one that's resonant. ... > give me some general clue as to where I should be looking. ...
    (sci.electronics.repair)
  • General monitor question: screen resolution relay?
    ... In all the VGA & SVGA monitors I've used there seems to be a relay ... that clicks when the screen rate changes. ... I'm guessing that this is ...
    (sci.electronics.repair)