lagasse@biomed.UUCP (Robert C. Lagasse) (05/31/85)
I have tried building a Jacob's Ladder using a 2-transistor oscillator
feeding a T.V. flyback transformer but I have had problems with it:
1) The transistor oscillator wants about 10 amps @ 12VDC. An AC
line powered circuit would be more elegant.
2) The H.V. arc produced wants to stay small in length. That is, it
does not want to climb up the rods and lengthen and finally break away
unless I blow on the arc with an airstream (really!). What am I doing
wrong?? Any help is much appreciated. Thanks.
Bob Lagasse @ MGH Bostonben@moncol.UUCP (Bennett Broder) (05/31/85)
I have always been facinated by the Jacob's Ladder, and wanted to build one. I was under then impression, though, that it required an expensive neon sign power supply and was pretty dangerous. If anybody out there has plans for an inexpensive and relatively safe model, I'd be curious to see them. Ben Broder ..vax135!petsd!moncol!ben ..ihnp4!princeton!moncol!ben
edward@ukma.UUCP (Edward C. Bennett) (06/01/85)
I once built one in high school. It was physics class and we got
the day off. Heh Heh.
Anyway, I used a little ~20,000 volt transformer that we normally
used to run some gas discharge tubes. (Is that the right name? You know,
glass tubes filled with various gasses. Different gasses make different
colours.) My 'ladder' wires had to start about 1/4" apart and the arc
rarely got more than an inch long. Nothing like these 3 inch muthers
you see in evil scientist's labs.
--
edward
{ucbvax,unmvax,boulder,research}!anlams! -|
() {mcvax!qtlon,vax135,mddc}!qusavx! -|--> ukma!edward
| |
|-- {decvax,ihnp4,mhuxt,seismo}! -+-> cbosgd! -|
/|--- {clyde,osu-eddie,ulysses}! ---|
| \ _
\___/ \= Support barrier free design
"Well, what's on the television then?"
"Looks like a penguin."igor@vortex.UUCP (Igor) (06/03/85)
What do you need it for? In my own experiments, I've found that inducing life into non-living materials doesn't require such "flashy" instrumentation. I did use a Jacob's Ladder in one of my early matter transmission experiments, but later found that the ringer from an old telephone worked just as well, and also allowed direct distance dialing. [Igor]
jans@mako.UUCP (Jan Steinman) (06/03/85)
In article <344@moncol.UUCP> ben@moncol.UUCP (Bennett Broder) writes: >I have always been facinated by the Jacob's Ladder, and wanted to >build one. I was under then impression, though, that it required >an expensive neon sign power supply and was pretty dangerous. The ignition transformer from an oil-fired furnace is a neat thing to have in your junk box. Besides the Ladder: rectify it to make an ion generator or a plant growth stimulator, hook it to two closely-spaced pieces of chicken wire or harware cloth (coat with sugar water for best effect) to make a bug zapper, etc. Look in the Yellow Pages for HVAC shops that specialize in oil-to-gas conversions -- they might part with one of the useless (to them) things for a reasonable price. As to safety, these things put out about 10 mills, which is enough to start fibrillation if passed through the heart, but I am living testimony that the jolt from one of these, while highly unpleasant, is not likely to be fatal! -- :::::: Jan Steinman Box 1000, MS 61-161 (w)503/685-2843 :::::: :::::: tektronix!tekecs!jans Wilsonville, OR 97070 (h)503/657-7703 ::::::
zben@umd5.UUCP (06/03/85)
In article <72@biomed.UUCP> lagasse@biomed.UUCP (Robert C. Lagasse) writes: > I have tried building a Jacob's Ladder using a 2-transistor oscillator >feeding a T.V. flyback transformer but I have had problems with it: >... > 2) The H.V. arc produced wants to stay small in length. That is, it >does not want to climb up the rods and lengthen and finally break away >unless I blow on the arc with an airstream (really!). Mine is a 12 KV neon sign transformer with coat-hanger-wire electrodes. The bottom gap is about 1/2 inch and the top gap about 5 inches. The major causes of "hanging up" I have seen in almost 20 years of experimentation: 1. Too much "slope" - the electrodes separate too quickly. The effect of a Jacob's ladder is caused when the hot air generated by the spark rises. As hot air is easier ionized than cold, the arc will rise with the hot air but if the slope is too much the effect of the electrodes separating will swamp the hot air effect and the arc will stay at the bottom. 2. Electrodes not straight. If the electrodes have little bends or knees in them the arc will tend to hang up at that point. The finest ladder I have seen was at the Ben Franklin Institute in Philadelphia, PA. Their electrodes were perfectly straight and nearly four feet long with a very gentle slope - the arc took literally 6 or 7 seconds to go the distance. My advice to you is to rework your electrodes. Make sure that they are as straight as possible, with a gentle slope (15 degrees or less) and find out exactly where the arc is hanging up. Examine that point. If there is a bump of metal or anything there, FILE IT DOWN! Sharp points give off arcs much more easily than flat areas. (Yes I know why, but it's too involved to try to explain it here). Good luck, and remember, this kind of electricity can kill! -- Ben Cranston ...{seismo!umcp-cs,ihnp4!rlgvax}!cvl!umd5!zben zben@umd2.ARPA
keithd@cadovax.UUCP (Keith Doyle) (06/03/85)
[.............]
No, an expensive neon sign power supply is not required, an inexpensive
neon sign transformer is (unless you think $10.00-$30.00 expensive).
I would suggest you look in the phone book under 'signs' for someone who
does neon sign repair. You can usually obtain a used 15kv transformer
relatively cheap from such an outfit. I have a 15kv 60ma transformer I
use for a Tesla coil. I only paid a couple of bucks for it (this was in
1971). 15kv 30ma transformers are common, and for a jacobs ladder you probably
can't tell the difference. And basically, that's it. 115v in, and 15kv out.
All you have to do is come up with a couple of metal rods and some sort of
insulative base, (I've used plexiglas). You want to position
the rods such that at the bottom, they are about 1/4 to 1/2 inch from
each other, and at the top, about 2-1/2 to 3 inches. Some time ago, I made
one using a curtain rod (the cheap kind with the 2 pieces that slide in and
out of each other). I took each piece, and flattened about 1-1/2 inches on one
end of each one, drilled mounting holes in the flattened end, and bent
the end and used this angled flange to mount it to my insulative base.
With this setup, I could get the arc to rise 2 to 2-1/2 feet. The closer
the rods are to being perfectly parallel, the farther the arc will climb,
but if they are completely paralell, the arc will probably stay at the
bottom. If you have trouble making it climb, try making the distance between
the rods at the bottom a little larger, and/or spreading the rods at the top
a little more.
* *
* *
* *
* *
* *
* *
* *
__ * * __
****** ******
[] []
[] []
[][][][][][][][][][][][][]
key: * = metal rods
[] = insulative base
-- = screw heads (for mounting rods to base)
Attach the two output terminals of the transformer to the two rods, and
away you go.
Again, the usual warnings: 15kv is DEADLY! And, many times the
center tap of these transformers is connected to the metal case. If you
mess with this with the transformer sitting on the concrete floor of your
garage or something, you will have 7.5kv between either insulated output
of the transformer and ground. I used a jacobs ladder like this for a
Halloween's haunted house once, and encased the whole thing in clear plexiglass
so that no one could get near it. ( with slight ventilation at the top)
Use in well ventilated area, as OZONE is a major by-product.
Keith Doyle
# {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithdkeithd@cadovax.UUCP (Keith Doyle) (06/03/85)
[............]
Sorry about that Jacobs ladder diagram, I haven't mastered vi's auto-indent
here's the correct diagram:
* *
* *
* *
* *
* *
* *
* *
__ * * __
****** ******
[] []
[] []
[][][][][][][][][][][][][]
key: * = metal rods
[] = insulative base
-- = screw heads (for mounting rods to base)
Keith Doyle
# {ucbvax,ihnp4,decvax}!trwrb!cadovax!keithdfaunt@hplabs.UUCP (Doug Faunt) (06/04/85)
> an expensive neon sign power supply and was pretty dangerous.
I used to (20 years ago!!) dig neon-sign transformers out of the trash
at local companies (back east), that were bad on ONE SIDE only. The
other half produced plenty of voltage for a Jacob's ladder. As far as
danger goes, we would draw arcs to our skins with only very minor effects
to show for it, and run high voltage through our entire bodies, and none
of us dropped dead. The winding resistance was high enough to limit the
current to acceptable levels.
--
....!hplabs!faunt faunt%hplabs@csnet-relay.ARPA
HP is not responsible for anything I say here. In fact, what I say here
may have been generated by a noisy telephone line.gnome@olivee.UUCP (Gary Traveis) (06/04/85)
> > I have tried building a Jacob's Ladder using a 2-transistor oscillator > feeding a T.V. flyback transformer but I have had problems with it: > > 1) The transistor oscillator wants about 10 amps @ 12VDC. An AC > line powered circuit would be more elegant. > 2) The H.V. arc produced wants to stay small in length. That is, it > does not want to climb up the rods and lengthen and finally break away > unless I blow on the arc with an airstream (really!). What am I doing > wrong?? Any help is much appreciated. Thanks. > > > > > Bob Lagasse @ MGH Boston Ok, the mod I would make to this circuit is to put it in drawer and forget it. Next, go to a junk yard and try to dig up an oil-burner HV ignition transformer or neon sign transformer. The oil burner transformer is the better choice of the two because of the higher current handling capabilities. Next, just get a couple of steel/stainless rods and bend them into a gentle V shape. Mount them to a good non-conductor (the posts of the transformer is best). AND AWAY YOU GO. The reason why the arc won't move with the other method is because there isn't enought heat created by the arc to draw it upward. Also, flyback transformers are highly resonant and a pain to use. Gary
jeff@abnji.UUCP (jeff) (06/04/85)
[spritzensparken!]
I have made a Jacob's ladder using neon sign transformers and
tv rabbit-ears. It made nice thick white arcs that zidded up the ladder.
7.5kv was nice, 15kv was better, making arcs >1 inch.
I tried using an igniter cell and a step-up transformer
with a relay in series with itself to commutate the primary but the sparks
produced were scrawney - weak thin sparks. I guess that a constant
current of a few milliamps is needed to really ionize the air and give a
spark with some plasma to it. I guess that safety and impressive results
are mutually exclusive.
I notice that the Jacob's Ladders in the movies are in glass tubes.
This is not only for safety but also confines the ionized air to
aide the sparking process, and eliminates the problem of drafts blowing
the spark out. Plastic tubes won't provide any insulation.
It's glass or nothing. Even the standoffs used for neon signs are glass,
so take care with that insulation!
For safety, I stayed 3 feet away from the thing when in operation
and it was mounted on a wood base, held up by a wood chest on a wood floor.
The neighbors probably weren't too happy with the EMI interference.
Jeff 'neon red' Skot
at the barely illuminated ATT IS
Somerset, NJ
{ihnp4 | mcnc | cbosgb} abnji ! jeffron@brl-tgr.ARPA (Ron Natalie <ron>) (06/04/85)
Well I've got a surplus 0-60KV power supply in my living room, I'll have to give it a try. -Ron
punia@uvm-gen.UUCP (David T. Punia) (06/05/85)
While it is true that many of us have lived through being zapped by
HV transformers, AC power lines, automotive ignition coils, etc.,
don't be fooled into thinking, and PLEASE, PLEASE don't promote the
idea that it is a safe practice. It is a very dangerous game. The
human heart can be made to fibrillate (quit working right) with a
current of as little as 5 MICROAMPS. There are many variables, such
as skin resistance, source impedance, current path, and timing in
relation to your heart's rhythm that enter into it. Nonetheless, it
can, and does happen that the right tickle at the right time will do
you in. PLEASE have the respect for high voltages that safety dictates!
With that said, I once built a nifty Jacob's Ladder using a discarded
neon sign transformer. A friend of mine was tinkering with it while
hot and inadvertently touched one of the high voltage leads. He dropped
to the ground and woke up half a minute later wondering what happened!
We used the same transformer another time to build a truly marvelous
Tesla Coil that would light a flourescent tube at ten feet. I'll probably
have cataracts in another 20 years or so, but at those frequencies
the current is harmess to the heart.
--
"Thunder is good, thunder is impressive;
but it is lightning that does the work."
Mark Twain
-----------------------------------------
David T. Punia, Dept. of Computer Science & Electrical Engineering,
The University of Vermont, Burlington, VT 05405
802-656-3330
USENET --> ....!decvax!dartvax!uvm-gen!punia
CSNET ---> punia@uvmtonjon@fluke.UUCP (Tony Johnson) (06/06/85)
> > an expensive neon sign power supply and was pretty dangerous. > > I used to (20 years ago!!) dig neon-sign transformers out of the trash > at local companies (back east), that were bad on ONE SIDE only. The Speaking of high voltage fun...anybody build a tesla coil in recent memory? We had one in high school and the arcs one could draw were quite phenomenal. It also messed up TV and radio reception over a large area...REAL high voltage excitement!!! Tony Johnson John Fluke Mfg. Co., Inc. Everett, WA The above is from my head and not from my companies. So don't blame them if you don't like what I said. They just hired me...
brad@kontron.UUCP (Brad Yearwood) (06/10/85)
For a truly impressive Jacob's Ladder, go see the electrical demonstrations at the Deutsches Museum in Munich. The transformer is about the size of two 3-drawer filing cabinets side-by-side. I think the voltage was around 120Kv, but with a fairly high current capacity. It seems reasonable that a high current would heat a larger amount of air around the arc, making the arc travel up the electrodes. The luminescence seemed to persist in a little ball after the arc had come off the top of the electrodes. The noise was an impressively menacing combination of hum and hiss. Additional demonstrations included a noisy 300Kv arc between two electrodes separated by a piece of thick plate glass at least a meter square - the arc forms a pattern of radial lines across both faces of the glass plate, a man in a Faraday cage attached to the same 300Kv source, and a 1+Mv capacitor bank for small scale (small scale, large noise) lightning simulations. Fun!
gnome@olivee.UUCP (06/11/85)
> Well I've got a surplus 0-60KV power supply in my living room, I'll > have to give it a try. > > -Ron WARNING!! DANGER WILL ROBINSON !!! I would like to add this little tidbit to the Jacob's ladder discussion -- STAY CLEAR OF HIGH VOLTAGE DC SUPPLIES ! ! ! ! All of the discussions about neat arc generating devices has been fine - but it should be made clear that HVDC supplies are very different animals. Unlike 60Hz AC arcs produced by neon sign transformers, HVDC arcs from surplus laser/xray power supplies are loud, unpredictable, and sometimes fatal. Most (big) HVDC supplies arc over in the following manner - 1) Upon power-up, nothing happens for a few seconds (uh-oh) 2) as the supply charges its internal capacitors, a slight crackling sound might be heard around the outputs of the supply. 3) The arc (to be) usually looks for the least-plausible path to ground and jumps with an incredibly load BANG! 4) The power supply starts charging again and looking for a new place to arc to (the old spot isn't there anymore). At BTL, we had a display terminal that ran with a 10KV DC tube (CRT) supply. One time, the HVDC jumped to a deflection board and literally vaporized a TO-220 transistor; the plastic case and one of the three leads became a little black crater. Low frequency HVAC can be fun and (reasonably) safe. HVDC can easily blow you away and stop your heart. As they say on the Hitchhiker's Guide - "Whole lots of No-Fun!". Gary