m kinsler wrote in news:1182580014.502103.44600
@g4g2000hsf.googlegroups.com:

I'd like to try building an oscilloscope from an old CRT monitor or TV
set. The purpose would be to display audio waveforms at one of the
science museums I work with; there's no calibration necessary.

I've tried the various sound-card based 'scope programs available for
the PC, and none of them show sufficient detail; I really believe I'll
need an analog device to show things like the difference in the audio
waveforms of different musical instruments. The big screen of a TV
set would be helpful for demonstrations.

I understand that this is a totally novel concept, and that Google
doesn't yield a single thing on the subject except for the twenty-six
thousand articles listed under "TV oscilloscope."

But I must say that those plans seem either oversimplified or more
theoretical than practical. The problem I keep concerning myself with
is that the deflection yoke of a CRT is, or at used to be, part of the
high-voltage circuit.

Additionally, we run into the problem that a magnetic deflection coil
is an inductance, and thus won't accurately show, say, a waveform
that's not pretty darned sinusoidal. I would imagine that any corners
on a waveform sent into a vertical deflection coil would be converted
into spikes.

So I'm lazy. Has anyone actually done this sort of thing and actually
had it work to any degree? Thanks.

M Kinsler


You might try a different approach, there are A to D capture devices that
will turn any computer into a scope.

Cheap monitor, cheap computer, A to D capture device and you have a scope
that will show detail and can be seen by the class.

You can also feed the video from the computer into a modulator and put it
onto your large screen or projection tv.





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please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

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