[Noisebridge-discuss] High-Voltage

John Butterfield johnb003 at gmail.com
Mon Mar 11 21:08:27 UTC 2013

Honestly I haven't done much with vacuum tubes yet, so I'm not that
familiar with their operating voltages.  I guess if you make your own you
can tune them for whatever voltages you want.

I've built a couple of my own hv power supplies.
Since LCDs have completely displaced the use of CRTs, people are always
junking their old CRT TVs and Monitors.
I had an endless supply of these, and I figured I'd learn how to build a
high voltage power supply from one.
I didn't have much experience going into it, but I succeeded on my first
one and it still works >< So now I just have an excess of crt monitor
flyback transformers and mainboards waiting to be gutted for their 2kv
capacitors and power mosfets.

The only though I purchased was a few 555 timers.  Which I did need a few
of because it took me a while to learn how NOT to fry them with kickback
voltage from the transformers.

Anyway, as for how high, I guess it depends on the application.
With a flyback transformer you can go from around 20-60kv depending on the
flyback and the age of the crt it came from.
These power supplies are quite low current.

I also built a power supply using 2 MOTS (microwave oven transformers),
which spits out around 4kv at at a very high current.

They behave quite differently, and it's interesting to work with both. One
of my favorite papers from Tesla is his article On Light and Other High
Frequency Phenomena. In it he talks quite a lot about the characteristics
of the high voltage power supply he used as the source for many of his
experiments. One of the characteristics, he described was that often it was
hard to draw an arc, and so his spark gap had a handle with a spring that
he could use to temporarily reduce the spark gap distance to get things
started, and then he finds that once the arc is formed it wants to stay
formed which is why he started creating all kinds of new ways to blow the
arc out once it formed.  One of which being just using a magnetic field.

This puzzled me at first as I was using my flyback transformer and there
characteristics were very sharp sudden discharges and they had no problem
forming at all. It wasn't until trying the MOTs that I saw a different side
of the story. Using the MOTs, the voltage was much lower like around 2kv
when I started, and I too found that it was difficult to form the arc, it
required a very small spark gap distance. And also, once formed due to
there being much more current, the arc stayed formed and grew like a flame
even as I widened the gap.

Here's one of my first tests with the flyback transformer:

Here's the same thing but now with a capacitor (With more current per
discharge, the magnet is more effective at disrupting each burst from the

Here's some videos using the MOTs

There are free energy advocates who have made claims about phenomena
associated with certain types of HV discharges.  My personal stance on the
subject is, I think people who advocate ideas without any kind of evidence
or scientific approach are a burden to the scientific community. However,
I'm also disappointed in a large part of the scientific community who
outcast any and all work related to the claims of such extremists. Both
viewpoints are equally dogmatic and have no place in science.  That said,
the side of having a large body of evidence suggesting something works a
certain way, and then hearing claims made that it may behave differently is
understandably dismissible as IMPROBABLE, but I would not go as far as to
condone the claim as false right out. I think it's important for people to
revisit largely accepted ideas and attempt to poke holes. I wouldn't spend
MY time trying to make a mechanical perpetual motion device, and I'd
probably think it fruitless for whoever tries, but if someone is adamant
about doing it, I wouldn't try to convince them otherwise. So, all that to
say, I'm not opposed to exploring some claims even if they come from not so
reputable sources.


On Sun, Mar 10, 2013 at 11:02 PM, John Ellis <neurofog at gmail.com> wrote:

> CRTs go up to around ~24KV at the Extra High Tension supply.
> Transformers, more specifically, the Line-Output Transformer can be good
> for high voltage experiments.
> -John
> On Sun, Mar 10, 2013 at 11:37 AM, jim <jim at well.com> wrote:
>>     I'm interested and willing to help.
>>     What do you mean by "High voltage"? I'm thinking
>> anything over 240 VAC (about 360V peak to peak).
>>     Vacuum tubes work with anything from about 60VDC to
>> 500VDC (or so).
>>     440VAC circuits have of close to 700V. Mircrowave
>> ovens I've seen have transformers that present internal
>> voltages to something like 800V. Cathode ray tubes use
>> from 1500VDC to 5000VDC.
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