A Jacob's ladder is a device that basically shows off the power of high voltage supplies. It is built with two long conductors in a 'V' shape with the bottom points close but not touching. When you apply a high voltage current it will arc across at the bottom. As the air heats up and rises the resistance is lowered and the arc travels upwards. When it reaches the top the resistance at the bottom of the 'V' is now lower than at the top where the arc is because the air is no longer being heated under it. At the point the arc disappears and the process starts over again.

 

Obviously, a higher current power supply will heat the air up more and allow the arc to be drawn out more making it longer. A higher voltage supply will allow the bottom of the 'V' to be farther apart. You can use any “high” current power supply for a Jacob's ladder. The “high” is in quotes because it is relative to the voltage. A 2v 1A power supply would not be high current but a 12kv 30ma supply would. I used a Neon Sign Transformer(NST) to make this Jacob's ladder.

 

If anybody is interested I can post detailed instructions for making a Jacob's ladder from an old TV or computer monitor. There is no need for powering it directly from mains. And the circuit is harmless because of the low current output.

 

 

This picture is from a 12kv@30ma NST. It is about 2' long and the top is about 3" apart. It is impossible to get this kind of performance from a flyback transformer in a TV though.

Plz could you send me instructions?

You got a video of it working?

 

12kv eh? Thats still smaller than the 100Kv static shock you get in woolworths....

12kv eh? Thats still smaller than the 100Kv static shock you get in woolworths....

 

No, you misunderstand. A static shock is an extremly fast discharge that lasts for a fraction (a very small one) of a second. The transformer I used could easily stop your heart and resperation.

 

Ill write some Instuctions for driving a flyback transformer later. They output 10-30kv at around 1ma which is harmless.

Video

do you get an odour of O3 from electrolysed O in there, I imagine it must be quite good for doing that.

 

Also, what exactly is it that you can see? Electrons? Electrons emitting photons?

You're seeing extremely hot air/plasma.

teach me oh great one.

 

Timed exposure so the arc traveled all the way to the top.

what sort of temps is this plasma?

Extremely hot. It would burn/melt just about anything you put in its way. When I was younger and first got a flyback working I would play with it and tell my friends to put the output on the back of his fingernail. It nearly instantly burns thought your fingernail giving you a nasty shock.

 

A flyback is actually harmless because it runs at about 30khz-60khz, what you really feel when you touch the output is the burn. A lower frequency would not travel through your fingernail but that just shows what temperature its capable of.

i must make one! my mother would love me doing this at her house, im sure.

 

please instruct. : D

I always wanted to make an arc welding device of some sort that I could use to cut funny shapes from metal sheets. Well, too bad I suck at electronics. But that stair-thingie seems quite nice (plasma is always nice ) ).

Notice: SFN does not endorse the mutilation of your playmates' fingernails.