Re: DRSSTC - I think I heard Cross Conduction...

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Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>





> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
>
> about or justify their expense.  The plain old ceramics should do just
fine.
>
> So before pulling the H-bridge to add the caps, I tried the caps across
the
> output first to see how well they stop the noise at that point

I think that idea must have been caused by a stray cosmic ray passing
through your brain and triggering daft idea neurons LOL (not offense
intended).
>

>
> http://drsstc.com/~terrell/pictures/TraceBlown.JPG
>
>
Now I know what your layout looks like.
If you lay out an other board put the power input connection next to each
other and the same for power output.
Definitely not on opposite edges. Keep the traces next to each other  i.e.
minimize the loop area.
Try to think the cennections as a pair only just seperated sufficently for
insulation. Same for the decoupling/bypass cap loop.

With the power loops you appear to have, a scope probe and its ground
connection will form a nice pick up loop to them.
Try grounding the scope probe tip with its ground connection to form a loop
and see what you can pick up.

Nice tight twists on the signal wires, thats good given the big loops on the
power lines.

I thought you where using bricks. Do you have the spec on these wimpy
looking devices?

Robert