Fiber Optic Tesla Coil Probe Plans
Subject: Fiber Optic Tesla Coil Probe Plans
From: Terry Fritz <twftesla-at-uswest-dot-net>
Date: Mon, 16 Aug 1999 22:41:14 -0600
I have been using my forth generation fiber-optic probes now for about a
year to observe and study Tesla coil voltages and currents. These probes
completely isolate my ever increasingly expensive digital storage
oscilloscope (the Tek b210 now sells for $1200!!) from my Tesla coils
signals. Many of my papers and babblings here on the list are based on
information gained from these fiber optic probes.
Finn is working on making a bunch of PCBs for my fiber optic probes. This
got me all inspired to clean up the schematics, parts lists, placement
diagrams... for the probes.
These files are too complex to easily post on the net*. So I will have to
resort to snail mailing them to those that are interested. Send me your
name and address EXACTLY as it needs to appear on a mailer (this is REALLY
important for those that have odd foreign addresses). I will request that
you send me 10 bucks to cover the cost of the duplication and all (high-res
inkjet) but I am not demanding it. This makes it easier for those that
live in other countries not having to worry about money conversion and all
that BS (I like gifts though :-)). I'll just write it of to my infinite
Tesla coiling budget. :-$ Since the probes work at such high frequencies,
they really need the "right" PCBs and surface mount components to preserve
high frequency and phase information.
I will also sell parts. The above comes with parts lists with prices.
Just let me know EXACTLY what you need and send me the amount (I'll cover
the postage) and I'll get the parts to you ASAP. If I have to order a
bunch of stuff, it make take an additional week or so. All the parts are
also available from Digi-Key and the part numbers are all given. However,
ordering a single surface mount resistor and such can get old from Digi-Key
were I can just stuff them in an envelope. I keep all the parts on hand
for emergencies so I have all the stuff usually. There are "certain
countries" that I am not allowed to send high-tech fiber optic parts to but
I think most of you are "cool".
The whole thing will cost $300-400 bucks so be aware of that... It has
surface mount parts that need to be soldered and the PCBs may need small
holes drilled (I'll sell the drill bits too :-)) I simply don't have time
to build them up but perhaps someone else would offer to do this for those
that don't feel able to do it themselves. If, for some reason, Finn can't
get the PCBs made, I'll offer photo art and/or PCBS made by me if you can
stand some wait. I have the fancy ultraviolet lights and etching stuff but
Finn's solution is much much better....
The probes are two channel and are meant to go to a dual channel
oscilloscope. I have always used storage scopes with it but fun should be
had with non storage types too. The fiber cable is 10 meters long and is
125uM glass fiber with silicon gel filled polypropylene cover so there is
no doubt as to the isolation. Longer cables can be used up to about a
kilometer for larger coils :-) They can either input -5 to +5 volts or -10
to +10mA input signals from transducers of mine or your design. There are
two outputs. A 2MHz bandwidth calibrated output and a 40MHz "raw" output
direct from the receiver ICs. The probes have always worked fine for me
but they can get saturated by the giant initial burst from the spark gap.
I have fried a few things but once it was my fault and once the streamer
got hold of the fiber cable. Not a big deal... I also have a top terminal
sphere with input and output current transducers that I can supply details
to also. Basically, I just mount the transmitter and transducer guts in
the sphere... It is all pretty straight forward for electronics types...
Of course, I'll answer all questions and help people out with construction
off list. If it really gets bad, you can send it to me and I'll trouble
shoot the tough cases if needed. This is all sort of a big deal for me so
I plan on doing all this only once. If you are at all interested, at least
get the plans now.
Send inquires to:
and requests for the plans (and hopefully money too)...
641 South Loomis Ave.
Fort Collins, Colorado
I know there is interest on the Tesla-2 list and some German lists which is
great! However, despite the fact the my grandmother was a German teacher,
I need all requests written in English... Also, I only subscribe to this
list since this one is all I can handle :-O
Thanks and I hope you all enjoy playing with probes as much as I have. You
will finally be assured that I didn't make all that stuff up ;-)
* There are some old probe plans and details at: