peterson@milano.UUCP (09/16/86)
In article <1249@utastro.UUCP>, butch@utastro.UUCP (Allan Butcher) writes: > > Does anybody know how to make a Jacob's Ladder ??? I made one as a kid in high school. I went to a Neon Sign place (look in the Yellow Pages under "Signs"). They always seem to have lots of old neon signs laying around in the back. I bought a used transformer from them. It was about the size of an anvil and weighed as much, cost me around $10 I guess. Took in 110 volts and put out 12,000 volts. Then a couple of wires from the output in the shape of a V (I think I stripped some 10 or 12 gauge wire) and I was in business. After watching it for a while and burning little holes in paper held between the two wires, I couldn't figure out what else to do with it and was pretty scared of getting electrocuted, so I put it off in my parent's garage and I suspect it is still there (20 years later). -- James Peterson peterson@mcc.com or ...sally!im4u!milano!peterson
jans@stalker.gwd.tek.com (Jan Steinman) (09/17/86)
In article <1249@utastro.UUCP> butch@utastro.UUCP (Allan Butcher) writes: > Does anybody know how to make a Jacob's Ladder ??? You know, the big >upright "V" shaped apparatus in the mad scientist's laBORatory that threw >an arc of lightning up its sides. I know that it takes a lot of voltage, >but what else, and how ??? Call up local heat&air installers -- especially those who specialize in gas conversions. Ask them if they have any old oil furnace ignition transformers as scrap that they'd be willing to part with real cheap. The transformer will have two ceramic-insulated screw connections about 1 1/2" apart, and other connections (usually behind a small panel) for 117 VAC. Get 2-3 feet of bare 12-18 gauge (it must be self-supporting) copper wire. Cut the wire in half and attach each half to the HV connections. Make a sharp bend in the wires at the connections so that they come within 1/2 to 3/4 of an inch of each other, and widen gradually until they are 3 to 4 inches apart at the top. Plug it in and watch the show! It may take some diddling to get the spacing right -- remember to unplug it before adjusting! :::::: Artificial Intelligence Machines --- Smalltalk Project :::::: :::::: Jan Steinman Box 1000, MS 60-405 (w)503/685-2956 :::::: :::::: tektronix!tekecs!jans Wilsonville, OR 97070 (h)503/657-7703 ::::::
kim@amdahl.UUCP (09/18/86)
In article <1249@utastro.UUCP>, butch@utastro.UUCP (Allan Butcher) writes: > Does anybody know how to make a Jacob's Ladder ??? You know, the big >upright "V" shaped apparatus in the mad scientist's laBORatory that threw >an arc of lightning up its sides. I know that it takes a lot of voltage, >but what else, and how ??? > >Allan Butcher and Dave Doss I made one many years ago when we converted the furnace in our house was converted from an oil-burner to natural gas. I just took the "starter transformer" (sorry, I don't know the correct buzz-word for it :-) ) and connected the primary to 110 volts (just like it was it the furnace application). Then a couple of un-bent garden variety wire clothes-hangers ... one to each of the secondary terminals, and that's it! The gap at the bottom was 3/4" inch or so, and on a dry day with no air motion, the top ends could be seperated by 4 and sometimes 5 inches. Putting a large diameter clear plastic tube around the wireshelped alot to curb air motion. Be VERY SURE to io and TV users for several blocks around. Sure looked impressive tho ... /kim P.S. The air needs to be pretty still so the heat generated by the arc will cause the air around it to heat up and rise. -- UUCP: {sun,decwrl,hplabs,ihnp4}!amdahl!kim DDD: 408-746-8462 USPS: Amdahl Corp. M/S 249, 1250 E. Arques Av, Sunnyvale, CA 94086 CIS: 76535,25 [ Any thoughts or opinions which may or may not have been expressed ] [ herein are my own. They are not necessarily those of my employer. ]
darth@fluke.UUCP (Rod Vaders) (09/18/86)
> > Does anybody know how to make a Jacob's Ladder ??? You know, the big > upright "V" shaped apparatus in the mad scientist's laBORatory that threw > an arc of lightning up its sides. I know that it takes a lot of voltage, > but what else, and how ??? > > thanks, > > Allan Butcher and Dave Doss > Univ. of Texas McDonald Observatory > Near Fort Davis, Western Territories, Republic of TEXAS > > > > > No bucks...no Buck Rogers...support your local observatory. *ACE THIS LINE WITH YOUR MESSAGE ***
will@nscpdc.UUCP (William Hobbs) (09/19/86)
I built a Jacob's ladder a couple of years ago. The source of voltage was
a neon sign transformer rated at 15,000 Volts at 30 milliamps.
The primary of the transformer was connected to the AC line, with a
power switch and a 2.5 amp fuse.
The secondary has ceramic standoffs that insulate it from the metal
casing of the transformer. The contacts of the secondary are small bolts,
which I attached to a couple of 1/4" steel rods. The rods were then bent
around the transformer (the ceramic standoffs are at opposite ends of the
transformer), keeping them at least two inches away from the transformer
casing. The rods were bent until they reached the middle of the top of the
transformer, and then given a shrp upward bend into the characteristic
"V" shape. At their closest point, the rods are about 3/8" apart, and
they diverge to about 2" at the top of the V.
To hold everything in place, I took an old speaker cabinet (approx.
18" X 10" X 6", placed it on its side, cut a hole in the box above
where the middle of the transformer would be, and mounted the transformer
inside. Covering the hole (which measures about 3" X 3") I put a nylon
block that had small holes drilled in it for the steel rods. The steel
rods then pass through the nylon block, bend toward their closest point
at the bottom of the "V" and go up about 18" from there. I enclosed the
rods in a glass tube that is slightly longer than the rods.
The arc produced by the Jacob's Ladder is quite strong, and could easily
cover a much wider gap at the top, but I was limited by the glass tube
I had.
When you turn on the Jacob's Ladder, the voltage is high enough to bridge
the short gap at the bottom of the two rods. Current passing through the
air at the gap ionizes the air, making it a low resistance path for the
current to flow through. It also heats the air, causing it to rise. Since
the ionized air conducts the current better than un-ionized air, the arc
follows the air up the ladder until the gap is too great for the arc to
bridge. At this point, the arc breaks, and starts again at the bottom.
Quite a conversation piece.
Incidentally, I got the transformer at a garage sale for $5.00, but
any neon sign company should be able to steer you to one.
Good Luck, Will
Will Hobbs, KE7OC nsc!nscpdc!will
National Semiconductor tektronix!reed!nscpdc!will