A Table Top DRSSTC Tesla Coil

Hi everyone,

Introducing my first DRSSTC. It’s a small tesla coil made to be portable and to make lightning at home. This coil is based of the amazing oneTesla pcb. I’m still in the process of doing a detailed write up at http://www.loneoceans.com/labs/drsstc1/!

As a learning experience, I wanted to go for something simple and nothing too fancy. I’ve had the fortune of being in the good company of other brilliant coilers (like Bayley, Tyler, Kramnik), and managed to get an older version of the oneTesla driver PCB, which runs this coil! I faced a couple of problems over the past few weeks but I’ve modified some parts and managed to get the coil working very well! See the video of it in action here:

Important specifications including calcs from JavaTC:

  • Max spark length – I don’t know yet, does >22″ sparks to free air and ground with ~100us on-time. More testing to come soon. Right now it’s limited by hitting the floor.
  • 222kHz resonant frequency (within 1%)
  • 2.4″ Diameter PVC Secondary, ~2000 turns of AWG36 for a 10.25″ length
  • 3.5″ Diameter Acrylic Primary, 6 turns of AWG 14 for about 0.8″ length
  • Single 0.101uF 2kVDC 942C CDE Primary Capacitor
  • 340VDC (120VAC rectified and doubled)
  • Roughly 100us on-time (in the photos here)
  • 2.2″ x 8″ AmazingOne spun toroid
  • Half Bridge of 60N65 IGBTs (seems to be similar to the 60N60 TO247 IGBTs)
  • Coupling = 0.22
  • Energy Transfer time = 9.87us

Performance has been pretty good. Originally, the coil used a 0.068uF 940C capacitor but that made my primary frequency about 19% too high and I lost a 60N60 half bridge. Increasing the primary to 8 turns of 14AWG (k=0.26) turned out to be a bad idea and I had a lot of racing sparks. After a few more coats of Polyurethane on the secondary, a return to 6 turns of AWG14 and a larger tank cap, the coil is in tune with a performance I’m very happy with.

This coil currently has a tiny built-in 19VDC laptop power supply for the electronics which uses the famed UCCs from TI as gate drivers to a GDT driving the gates of the IGBTs. Here’s a pretty photo of the ground ‘lighting’ strikes of the tesla coil:

Best Wishes!

 –  Guangyan
    23 Feb 2013

Direct-to-PCB Laser Printing

This is a cross-post from  muffin’s blog!

Over the weekend, Dan disassembled a laser printer that he found in the trash. He was able to tear it down to the point where he could fit a board in the (quite linear) print path and gave it a go. To his dismay, the board jammed and nicked the heating drum. I came over and we decided that by removing a metal guide and chamfering the edge of the circuit board, we’d have better luck – and we did! The print quality turned out pretty good, but the toner wasn’t fusing to the board. We figured that it was either a heat/pressure issue or a charge issue and called it a night.

The next day, Dan and I went to [miters](http://miters.mit.edu) to improve the process. We tried a whole slew of ideas include charge compensation, increasing roller pressure, and pre-heating the boards to get the toner to fuse. The last one did the trick. Although print quality isn’t 100% there yet, we’re certain that we can hammer out those last pixels and get this process rolling. We etched my first lab in 6.331 – a 4MHz 50-ohm line driver with 2 watts of output power.

More to come next weekend!