HV instrumentation for coil work, other

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Greg Leyh <lod-at-pacbell-dot-net> 

Hi All,

I seem to remember that Terry [and perhaps others] had developed isolated 
test equipment that could perform measurements on coils while floating at 
HV and perhaps relay the data to ground via fiber-optics or some such.

We have a need at work to measure transient waveforms in circuits that 
float at high potentials.  I've been trying to find a commercial vendor 
that offers a *compact*, bare-bones transient digitizer module that can be 
easily clipped into equipment under test, and downloads data to ground 
through FO cables.  (A Fluke scopemeter is far too large; hoping more for a 
single high-density SMT PC board, measuring about 1" x 2".)

Anyone know of a suitable product or homebrew design?  It's important for 
the floating digitizer portion to be as small as possible, and we'd like to 
get at least 50MHz [20nS] resolution.


Thanks,
Greg Leyh