Re: Electrostatic deflection?

At 08:57 AM 10/22/99 -0400, you wrote:
>
>I fully admit that I'm out of my league in these discussions...don't
>let these musings slow anyone down...
>
>I was thinking about the yoke issue, and am wondering if it's
>feasable to modify a vector (or raster) monitor to do electrostatic
>deflection. I think this is what oscilloscopes do.
>
>I can see a nice, simple assembly of four plates replacing a yoke,
>but I'd imagine you would need higher voltages to acheive decent
>deflection. After all, oscilloscope tubes are long and skinny.
>I think the nice part would be driving a high impedance instead of a
>low one...
>
>Is this possible or am I just dreaming? ;)
>
>Thanks,
>Frank

Although possible, I don't think that it is a good choice. Way back
when I was in college, my Emag Fields professor talked about the using
plates verses yokes for deflection in a tube. The plates are a lot
slower than using a yoke. He was an old school EE and his first job
was yoke design. It has to do with the fact that you have move all
that charge onto and off of the plates.

I'm suprised noone has talked about just rewinding an existing yoke. If
you are going to refit a raster monitor, the yoke form is already there
and the geometry is already done. I think that just cutting off the
old yoke wires and rewinding for vector is the way to go. Correct me
if I'm wrong, but I believe that the X coils just divide the toroid in
half vertically with each coil taking one half and the Y coils are just
wrapped on top dividing the toroid in half horizontally.

To find the number of turns can be done by counting up the number of
turns on an existing monitor or just a couple of plug and chug equations
since we know the inductance and wire size of an existing yoke.

-Chris

--
Christopher V. Moore -- Principal Engineeer
Heartlab, Inc. - 101 Airport Rd - Westerly, RI 02891 -- www.heartlab.com
Phone: (401) 596-0592 x113 - Fax: (401) 596-8562 - Email: cmoore@heartlab.com