Demo-Coil! (A New SGTC)

Pushing 48"+ streamers and ground strikes.

Pushing 48″+ streamers and ground strikes.

This coil was built as a general demonstration coil for MITERS after a tour for some high school students involved in FIRST robotics exposed that we had no working projects to show! Although oneTesla is now is a state where it’s completely “plug and play”, I’d rather have that somebody doing the plugging be myself or Bayley, and we’re not always around to give tours. The idea behind this coil is that it’s as simple as a Tesla coil gets (so anyone demoing it can explain it, hardly the case with a DRSSTC!), and that it’s bulletproof: anyone can plug it in without tuning or dabbling with software; it just works. The main components of the system are similar to my previous SGTC (“2-Day Coil“), but a 240V step-up variac, new secondary coil, and rolling base have been added.

Maximum spark length achieved was 4-feet; shoot me an email if you want to see it in action and are in the Boston area!

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Digital Salinometer

The completed Salinometer.

The completed Salinometer.

This device was built for a regional science team event using an opamp oscillator circuit with amplitude proportional to the conductivity (which in turn is proportional to the salinity) of a sample of water. The output is rectified and filtered, diode drop hidden by another opamp, to produce a DC voltage that is analyzed by an ICL7107 sample&hold/ADC/Binary to 7 Segment chip.

The design is a derivative of this person’s work.

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2 Day Coil

Outdoor ground strike.

Outdoor ground strike.

A spark gap coil that was built over a weekend at MITERS using some spare parts from my DRSSTC, 3 (overkill, overkill, overkill!) Maxwell pulsecaps, and a Raytheon high voltage radar magnetron transformer.

It produced 2 – 3 foot streamers and ground strikes, and was later revamped to become Demo coil.

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Dual 811A Vacuum Tube Tesla Coil

VTTC spitting out 3" sword sparks in its original configuration.

VTTC spitting out 3″ sword sparks in its original configuration.

This was my first major electronics project! After putzing around for a few months in 8th grade with a flyback transformer-powered spark gap coil, I decided that I wanted to take a step up and build something a little more interesting, so I selected one of Steve Ward’s early VTTC schematics and got to work. The performance of first version of the coil (pictured above) was somewhat underwhelming, but it worked! Later improvements more than doubled the spark length.

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