A small vacuum tube tesla coil (VTTC)

[climatex]

With a horizontal output tube, PL 500, from an old black and white TV. 10cm long secondary, 3.5-4cm free to air streamers.
Also added an interrupting circuit with a SCR/thyristor/whatever you call it. Got 6-7cm free to air streamers this way. Anode voltage comes from mains voltage multiplier, no microwave oven transformers or other trickery (the tube ain't for high power).

Whatdya think?

 

[daddles]

Nice job! And welcome to the forum. Do you put the coil to any practical use?

 

[climatex]

Other than jamming wireless transmissions and causing interference with sensitive electronics, not much. Might be useful for lighting up neon lights wirelessly.

 

[davenn]

Other than jamming wireless transmissions and causing interference with sensitive electronics, not much. Might be useful for lighting up neon lights wirelessly.

hahaha yes it will make a bit of noise on other gear

but well done, nice practical display. you should add a fluro light tube to the collection of things to bring near the discharge. it also should light up quitye well.

interesing to note the difference in the discharge between the contineous voltage and the interrupted one. a much cleaner display with the interrupted drive.

cheers
Dave

 

[climatex]

Two incandescent lightbulbs on the top load, take a look

 

[climatex]

Ah, almost nobody interested in high voltage here I see... just LEDs, microchips, blinkers and serial port circuitry. Gah

 

[davenn]

Ah, almost nobody interested in high voltage here I see... just LEDs, microchips, blinkers and serial port circuitry. Gah

hahaha
and Audio and in my case RF
I already have a nice plasma globe, it fulfills my interest.

But you didnt comment to my question earlier.... have you tried a fluro tube ?


Dave

 

[daddles]

Ah, almost nobody interested in high voltage here I see... just LEDs, microchips, blinkers and serial port circuitry. Gah

What's to like? All you can do is create sparks, make fabulous pictures of some guy protected by a Faraday cage next to huge sparks from e.g. a Cockcroft-Walton generator, or prank your friends (my youngest daughter loved to get me with a cheap ball point pen that would give you a jolt).

When I was a student, I used to do a demo for some of the elementary classes. I'd use a big old 1000 V Sorenson tube power supply to charge up this hefty bank of capacitors (I'd have to wheel all this stuff into the room on a big cart). Then I'd short the bus bar with a screwdriver and the acoustic side effects usually caused girls in the front row to scream. I still have that screwdriver with all the pits in it where the arc blasted the metal...

 

[climatex]

High voltage electronics ain't just making loud sparks or drawing arcs. For example, voltages up to 30kV were used in every single TV set with a cathode ray tube screen. That's how it worked. You can find a 700 watt 2kV supply in your microwave, too.

In fact, I was in progress of making a monster, but simple, 500 watt two-tube transmitter powered from a high voltage supply, ranging 10-100MHz /no filtering, modulation, just pure mess/. Not even this could fry you through the inside, it would be also possible to light up standard incadescent (i.e. filament, wolfram) lightbulbs wirelessly. Or it would be a great broadband jammer, ranging from shortwave frequencies all the way up to the CCIR FM broadcast bands... But I've decided to make a real x-ray machine instead, and I'm working on it at the moment.

@daddles, If you'd connect a coil to the capacitor bank and a high-current pulse thyristor in series, you would create an electric gun, a "coil-gun". Then, the stored energy isn't just shorted out to make a loud blast, but used to launch a small metal projectile. /Also done./

@davenn, yup, tried that numerous times with the fluorescent tube, but had none at hand during the camera work. I'll upload the result here just for the lulz

 

[Smithy49]

Ah - shorting capacitors with a screwdriver...

Fond memories.

 

[climatex]

Here's the fluorescent tube, lighting up wirelessly near the coil /the interrupter was switched off, ran in constant-wave mode, 3.5cm sparks/

Was lit up till moved 40-50cm away from the breakout point.

 

[Ian]

Climatex, we're basically asking for some self-moderation when posting something that could be dangerous to others. There are lots of people reading this site that may be novices with electronics and aren't aware of some of the dangers involved.

For example, if someone isn't familiar with running a laser diode, it may not be a good plan to suggest running LED/Laser's from a mains source - as there are some risks involved that require some prior knowledge!

 

[climatex]

Fair enough then.

 

[daddles]

climatex, it's great that high voltage stuff floats your boat. Many technical folks have reasonable experience with it; for example, I came across it when using e.g. photomultipliers, sputtering/etching, RHEED, Auger spectrometers, ion pumps, and a host of other things. You can do some neat things with it, but it's ultimately a tool like anything else.

As you mature and work more with people, you'll find that a gentleman (and gentlewoman) will acknowledge and encourage others' enthusiasm about the things that interest them and they will encourage discourse and warm fuzzies. The gentleman realizes that different fluids float different boats and that they all melt together in this conglomeration we call the world. The discerning gentleman also is on the lookout for new information from these interactions, as he knows how little he knows and that someone else's enthusiasm can rub off and provide new information. Thus, I encourage you to continue to proselytize your interests, but at the same time don't limit your interests to e.g. macroscopic high voltage stuff. Real advances often come from having a broad background in a variety of topics and making connections between them that others haven't seen yet.

I'm still pretty new to this board, but I'm tickled to find gentlepersons like steve, davenn, poor mystic, Resqueline, and others who are so kind as to share their knowledge, time, and experience. It's a nice resource.

 

[climatex]

Folks, high voltage circuitry and electronics in general wasn't ever really my cup of tea. My dominant hobby was always computers, programming (C, pascal/delphi, x86 assembly), cell phones and information technology in general. /And still it is! / I have stumbled upon high voltage electronics just like a blind person met a violin...

I remember that YouTube was then in its knees and first electronic hobbyists videos started to come up. One of them was a small high voltage flyback driver video, which I have seen, with a high pitched squeal and 2cm violet arcs. And then it happened: wow, that looks simple, what's the big black thing, is it safe, how can it work, I started to ask. From a brief discussion, I learned that the person built that generator from an ordinary computer monitor's parts. Me with my friend had back then a lot of CRT monitors which we sold or sent to the scrapyard, so we decided to open one up and desolder the big black thing with a suction cup on its end, that was then the high voltage flyback transformer itself. And, another questions started to come up: how can I make it work, what needs to be connected with,...

So I started reading some schematics of a basic, single-transistor flyback driver, the methods how it worked, necessary precautions, parts and all, that took me about a month. Finally, when I finished putting it all together and applied power, the suction cup started arcing, fizzling and whistling with a high-pitched squeal, indicating that it was working flawlessly for the first time. Yay.

So in spare time I used to fiddle with high voltage stuff and learned more advanced electronics through high voltage circuitry.

I'm not interested much in electronics now, though. I'm still slowly working on an x-ray machine that I had planned long before to construct, however now I'm just showcasing what I've made in the past.