Another small pile of crap.

Some bricks.

Infineon FS150R12KE3 (2 each)
Siemens BSM100GD120DN2 93 each)
MBM100GS12AW (2each)

Snubbers

KEMET C4BSNBX4200ZBLJ 1000V 2uF  (2 each)
Nichicon PMB21541100KSP 1500VDC 1.0uF (4 each)

Free. The "buyer" pays postage.

Cheers.

I am playing around with making another small DRSSTC. I have two reasons for this. First, I enjoy the mechanical
challenges of making a coil. I don't have a fancy machine shop or 3D printer and I like figuring out how to make
parts with a table saw, belt sander and drill press.

Second, like many coil makers, I would love to have a two inch high coil that shoots out twenty foot sparks.
My last coil is about three feet high (including electronics) and has about two foot sparks. Not my dream coil.

A while back I ran across Arc Attacks commercial "Thundermouse". It's about 18 inches high and puts out 24 inch sparks.
That's more like it.

The most interesting aspect of the coil to me is the curved primary.



I have  few questions about this design. First I assume the curved primary allows higher coupling while keeping
the chances of a secondary flash-over under control. Is this true?

The second question is the coupling of this design. According to the web-page it's 0.308 which I understand
is very high for a DRSSTC. I tried modeling the coil in JAVATC using a helical winding (ie bottom radius smaller
than the upper radius) and got 0.311 coupling. I also tried modeling the primary as a cylindrical coil
with the radius the average of the curved primary and again got a similar coupling factor.

So I guess the question is, is a DRRSTC with such high coupling realistic?

Cheers.

I have wanted to do a recreation of the classic quantum mechanics demo that show single photons
going through a dual slit can create a classic interference pattern.

Making the set-up did take some time but was reasonably straightforward. The source was a low power HeNe laser.
It goes through a rotatable variable attenuator and two fixed attentuators and then hits the dual slit. At the output
of the slit is a dielectric bandpass filter at 633nm (improves signal to noise ratio) and then into the detector, an old
Hamamatsu image intensifier. The output of this goes into a low light CMOS video camera.

It was easy to see that the set-up worked buy using a camera to integrate the output of the video camera. But I
wanted to see the photon hits add up in real time. I tried a few astrophotography stacking programs but they did
not show real time stacking. After asking about real time stacking on an astro website I was pointed to SharpCap.

It turned out to do the job. After some help from Robin, the programmer of SharpCap I was able to get a good enough
output which I videoed using a Nikon DSLR. Stacking is not integrating but it does work.

As I kind of expected getting software to do the job was more time consuming and frustrating than the mechanical set-up.
Here is a link to my Flickr site showing the video along with my best attempt to narrate what is happening.

https://www.flickr.com/photos/8763834@N02/53334653284

It's kind of fun to do these experiments even though I am finding nothing new. This one was especially neat because
after all is said and done, I have no idea (nor does anyone else) how this can possibly happen. One photon at a time
and you get an interference pattern. Real magic...

Cheers.

I build up a little ramped DRSSTC coil using labcoats circuit board. It made things super easy and the resulting coil is very fun. ~300kHz operating.
I was measuring the length of the sparks using a piece of glass tubing and got the silly idea of putting the glass tubing over the breakout.

Instant perfect sword sparks. And a funny hollow blowing down a glass tube noise.

I hadn't seen any other idiot try this so here you go. I'm the idiot in this case...

https://www.flickr.com/photos/8763834@N02/52958940125/in/dateposted/

The sparks are about 15 inches. No real tuning yet except for calculations. Running at ~5mS and 200 volts.

Cheers.

I talking with a friend of mine during a hike and a question he posed was kind of interesting. I had no answers
so I decided to post in hopes that someone might know. It's actually two questions.

Are there any advantages to operating a flyback transformer at resonance? Using a standard half bridge circuit
as a driver for the primary. To adjust voltage output you would change the operating (bus) voltage to the devices.

Second, is there any reason (using a standard half bridge driver with variable frequency and fixed voltage) to prefer
operating the power supply above resonance or below resonance? The supplies I have built are all below resonance
and I increase frequency to raise the voltage. But when I test the circuits on the bench I can get a variable output
by starting at high frequency and lowering towards the resonance to increase the output.

For operating at resonance he was curious if the circuit would be less lossy. I thought that it might be hard
to keep the driver at resonance since a high Q would make it difficult to stay on resonance as the buss voltage was
increased. In addition heating of the secondary might also change the resonance frequency. All just speculation,
I have no data...it just seems keeping the circuit tuned to that peak might be difficult.

Cheers.

I'm building another HV AC power supply for powering up homemade plasma tubes and a question has come up. It's not important,
more curiosity.

The plasma tubes are powered by AC because there is no internal electrode. I wrap a piece of adhesive copper tape around the base of the tube (area of about 60 cm^2) and use spring fingers to contact this electrode. As I understand it the foil acts as a series capacitance to the output of the flyback, conducting the current into the tube to create the plasma.

Recently I did a few simple experiments to see if this electrode could be smaller and still function well. The answer is yes, with a 12 cm^2 electrode things work quite well. Even smaller still works.

The question is what would be an optimal electrode? I'm not even sure what I mean by optimal. Best match to the flyback transformer?
I have seen some papers from Information Unlimited where the writer talks about matching different capacitive loads to a flyback but I never understood what he was talking about.

The circuit I am using to power the flyback is an old PVM400 from Information Unlimited. I got a bunch of these supplies from a plasma tube artist because they were broken. In most cases the output flyback was fried and I use 70's vintage color TV flybacks as a new output transformer. Another issue that I've never explored is optimizing the new flyback to the PVM400 circuit. The existing primary has always worked fine so I have not bothered to go any deeper.

I have some nice videos showing the xenon plasma toroid effect that has been mentioned on these forums. They are AVCHD format.
I also have them in mp4 but with watermarks from a trial video editing program.

I don't know how to attach videos so it would be nice to get some advice.

I recently bought an old Hamamatsu C2400-30 Single Photon camera along with it's controller. Unfortunately
the camera came without the cable connecting the controller to the camera. I have so far been unable to find a wiring
diagram for this cable.

The controller has a 12 pin connector and the camera has a six pin connector. Only 4 of the six pins are used. When I DC or scope probe the 12 pin s on the controller only four pins appears to do anything. The four active pins are ground(2) and 12 volts(2).

On the camera side I believe (from the wire colors) that two pins are ground and one is 12 volts. I can't figure out the fourth.

The wires inside the camera all go to a silver high voltage supply that supplies six voltages to the camera.

I was wondering if any of the knowledgeable people here can help me figure out how to power up this camera. I have several leads out but after two weeks none have helped.

I've got a measurement requirement that I want to solve as simply as possible. I have an old Geissler (?)
tube that I want to power up. The tube is supposed to run at ~1mA. I just bought a small neon tube
power supply 5kV @ 30mA. The tube is supposed to start at 5kV and run at ~1kV. I hooked it up and
it lights up nicely but I want to make sure I don't burn it out.

The tube is small and it seems reasonable that it is rated at about a watt.

The power supply is running at 30KHz. My first thought was to use a cheap DVM but I'm pretty
sure that they don't give good results at higher frequencies. I have a diff probe but it's rated to
about 1kV, so no go. A series resistor current monitor seems like a good direction but I don't have
much real experience in probing stuff that is sitting at high voltage relative to ground. I also don't like
killing equipment figuring out what works.

Any advice?

There was a thread a while back that had a cool looking little coil,

https://highvoltageforum.net/index.php?topic=1519.0

It looked fun so I went out to build it. The circuit is the same as the original post with one difference, the gate drive chip is a UCC37321 (the chip used in the original post is hard to find and I had some other gate drivers).



The circuit does not want to start up. I changed the polarity of the primary which made no difference. I attached a signal generator to the
cap/diode clipper going to the gate drive chip and can get action that way. The coil works but no self start.

How coils get started has always been a mystery to me. But I never had to understand the mystery until now. I once saw a Steve Ward design (Micro SSTC) that used a starting switch. And I seem to rember another small coil that used a free running 555 timer coupled to the feedback antenna as a starting signal.

Any enlightenment?

Cheers.