Navigation:

--Overview Write-Up

--Completed Designs and Variants

The Power Supply and Wiring -

A neon-sign transformer. Any size will do, but the size affects the maximum gapping of the rods, and the characteristics of the arc. The most common voltages are 12,000 and 15,000, to which higher voltages allow longer arcs. The most common output currents are 30mA and 60mA, to which higher currents make for fatter, brighter arcs with more heat, so the higher currents may climb faster, but is as of yet untested if it makes for a noticeable difference.

The wiring is commonly sold with the neon-sign transformer, or can be acquired from the local custom neon-sign company, which is also the most recommended source for good used neon-sign transformers. The wire is usually silicon based, and we commonly use 25KV rated wire, whereas the most we ever run through it was 15KV.

Note that we never actually interact the wire during operation, becuase 1/4 of silicon can easily be flawed enough to not be trustworthy enough for our comfort. This can be related to our designs where wire was used without adequate insulation - this is by no means a recommended approach, and we strongly discourage it, but only done because we are skilled enough with high voltages to be able to work with it in that manner.

The Parallel Rods (well, mostly parallel) -

The rods must, of course, be conductive... but they must also be smooth and able to handle the voltage and current load. Many possibilites are out there, but they must be sturdy so that they do not tip over during operation, as they can make nearby surfaces or entities electrified, making for a dangerous, even lethal situation... not good. The rods used in our projects are solid metal (usually brass) rods, commonly found in the threaded rod section of the local Home Depot or Lowes.

The rods must have the shortest gap be at the start of where the arc is desired to climb, so the arc jumps across there, and climbs to the top, where the top should be spread apart enough to "pull apart" the arc, encouraging it to repeat at the bottom. This can take some tuning, noting that the rods are spaced too far apart if the arc does not consistently make it to the top of the rods.

*Also note that if the rods are too far apart when powered up, that there will be no indication the rods are electricited.

Gabriel Electrode -

By using a Gabriel electrode, the gap at the base can be farther apart, as well as the entire run. Resistors only resist when there is electricity flowing through them, so before the arc forms, the Gabriel Electrode is effectively identical to the other two rods. Since it is closer to the active rod, the arc will form to the Gabriel. Since current is now flowing through the resistors, the second rod is much more favorable for the flow. This causes the arc to make the jump away from the Gabriel and onto the second rod.

Basically, once the arc is drawn to the Gabriel electrode, the arc 'sees' it fit to make the rest of the jump, where it reliably skips from there to the other rod, climbs to the top of the ladder, and repeats when it would rather take the jump to the Gabriel Electrode again as it is pulled apart at the top of the rods. Therefore, it only takes minimal tuning to get it to jump consistently, rather than having to bend the rigid rods into position, making for a smoother experience and operation.

So what is a Gabriel electrode exactly? Two high-grade resistors. Our designs use two 1M-ohm 2W *METAL FILM* resistors, which have been tested to be reliable for the 12KV neon sign transformer used, but that is just the experience with this particular ladder, and by no means a recommended value; the resistors must be fit for the driving power. The metal film build of the resistors is key, as ceramics will not enjoy the high voltage, and will simply burn-up angrily... They are run in series, and are tied from one rod's feed with a small length of HV rated wire. The electrode end CANNOT just be the bare resistor wire, which will be vaporized by the high voltage. The end is soldered to a nice piece of solid copper wire, and is bent to be at the base of the start of the "V" in the rods.

This Jacob's Ladder was designed with the knowledge learned from the previous units. The previous designs had an issue of not being consistent and relied on tuning for a complete run of the arc.

This design incorporates what is known as a "Gabriel Electrode" (see above), which is essentially an electrode at the base of the rods providing a semi-feasible path of least resistance between them.

The base for it all? a Tupperware box. Now hear me out... it is polyethylene, so it will cope with the HV nicely, and it has a locking lid, so it will not simply pop-off for any reason while operating. The other key is that it can be filled with sand, so it is a nice heavy tower that is easily broken down for easy storage purposes... The plastic also has the advantage of an easy clean-up of anything burned with the arc path, as long as it is not too hot and decides to melt/scar the plastic as it settles... has not happened... yet.

All the screws, nuts, and washers are nylon, and the rods are attached to the unit with aluminum lug terminals, so this turned out to be a very nice, reliable Jacob's Ladder...

Perhaps more video?