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Vacuum Tube Tesla Coil with low plate voltage...

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Inducktion

Mon Dec 19 2011, 03:48PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

I don't understand what he's saying, but I do understand the schematic.

How's the coil work with only 24 volts plate voltage? Wouldn't it work a lot better with a higher plate?

And does it necessarily have to be THAT vacuum tube? I have a really small tesla coil secondary I was trying to use with silicon... Silicon doesn't like high frequencies too much.

A small vacuum tube coil sounds like it could be fun to make.

teravolt

Mon Dec 19 2011, 10:50PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

google tranlate will english the whole page

M.A.D.

Thu Dec 22 2011, 05:29AM

Registered Member #4052 Joined: Thu Aug 11 2011, 04:43AM
Location: IN ,USA
Posts: 69

Here is the entire page translated:

Tesla generator with PL504

Who wants to generate high-voltage, must ask Tesla Nikola. His resonance transformer excited technically interested people for over 100 years. I wanted to try it sometimes, but only a relatively small primary voltage used. Everything is now operated on a 24 V wall adapter. That provides the heating for the PL504 and of a voltage doubling also equal to the anode voltage of but 60 V.

The 30 cm-long Tesla coil has coils from CuL 0.3 on a PVC pipe with the diameter of 1000 15 mm. A self-resonance of 3 MHz was measured with a HF generator and an oscilloscope. Now, everything depends on vote in the primary coil at 3 MHz. This used an old Drehko with air insulation. The primary coil itself has 18 coils from two wire cord with both veins are parallel. By the way the tripod was a floor lamp, the base a voting flywheel on a radio. The tube is from an old TV set.

And then there is a further small wire loop that is connected to the control grid is. This is the adjustable coupling capacitor with about 1 pF. Drehko and coupling capacitor are matched in operation on highest resonance voltage. For example a lamp in the vicinity is used as an indicator.

< > at the top of the Tesla coil the plier stands out. Here, you can spark a small plasma flame with your finger. If you hold more than 1 cm from the end of the finger, the flame on the wire remains. It is close to, it gets hot. But you can not get an electric shock. Nikola Tesla at much higher voltages has demonstrated this effect. He wanted to demonstrate the safety of alternating current at the time. But beware, at a frequency of 50 Hertz AC is even more dangerous than DC. High frequency, however, exists primarily to a warming. For very high performance is of course also no longer to be trifled with. Here it is just yet, if you can even see from unwanted interference.

Oh by the way, if just a few defective bulbs at hand, you can set again they with the generator in motion. Usually, the filaments are broken, needed only to ignite. There is no ignition problems with the Tesla generator. The high field strength reliably ensures an ionization of the gas.

The circuit was first introduced in my book "Tube projects from 6 v to 60 V".
See also: SCORM Tesla energy by Franzis
Branko Zupan has it built and further described the power supply:

Some of it translated a bit rough but it's not to bad. It would seem that the low input voltage and small tube is for safety. I do like the feedback that he used though, I wonder if it would scale up well.

Dr. Dark Current

Thu Dec 22 2011, 10:20AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

1. The coil works with 60 volts on the plate
2. The PL504 is a line output beam tetrode, these tubes are desined with large cathodes and very low "on" voltage, which allows them to pass pretty big currents at low voltages. However as you can see, the coil runs at a very low power, it's not even able to break out.

Steve Conner

Thu Dec 22 2011, 10:55AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

It's just the plasma tweeter circuit modified for a low supply voltage. C3 is a loading capacitor, it helps to get more output by stepping the impedance down to match a low voltage, high current tube. And C1 is the "antenna".

Personally I would get bored after 5 minutes, lose the wall wart, and hook it up to a doubler running off 230V mains. (use the 320V tap for the screen and the 640 for the plate)

M.A.D.

Thu Dec 22 2011, 09:36PM

Registered Member #4052 Joined: Thu Aug 11 2011, 04:43AM
Location: IN ,USA
Posts: 69

Why is the secondary not grounded, it seems like they made some sort of hybid base feed/transformer system. I have only ever seen one or the other used.

Also, why is C1 not commonly used as a replacement for the standard antenna, it looks far more practical than a huge antenna next to the coil, plus it could probably be more accurately adjusted.

Inducktion

Thu Dec 22 2011, 11:48PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

Uhm...What's a good vacuum tube plasma tweeter circuit to use? It seems most I've seen just have one vacuum tube in them...

LuceÅ¡

Sat Dec 24 2011, 02:23PM

Registered Member #4108 Joined: Sun Sept 25 2011, 11:43PM
Location:
Posts: 149

This a plasma tweeter schematic, all of the schematics are the same basic schematic, the only difference is, if you using a pentode you have to ground g3 to the cathode, and with a tetrode or pentode you have to modulate g2 by connecting it to some kind of voltage usually rectified mains. but g1 is always connected to the antenna. oh almost forgot you have to put a capacitor In parallel with g2 and ground to keep the grid from self destructing

hope that helps

Inducktion

Sat Dec 24 2011, 05:22PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

Where does the music input go?...

LuceÅ¡

Sat Dec 24 2011, 05:58PM

Registered Member #4108 Joined: Sun Sept 25 2011, 11:43PM
Location:
Posts: 149

Either modulate the voltage on g2 or modulate between cathode and ground

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