Project list

Tesla Coil

1. Init
2. Usage
3. Jacobs ladders
4. Schematic

Init

Time:

18.12.2005 10:14:58PM

Description:

How to make Tesla coil...

Pictures:

Cleaned packing of some sort of pills

Detailed view

Topload

Standing

Temporary look

Beta look (before presentation in school)

Note that cover is a bit melted by resistor... It's temperature was above 300 deg C and that's why it melted contacts also...

Usage

Time:

18.12.2005 10:29:44PM

Description:

What can you do with Tesla coil...

Pictures:

4 cronas is very hard to get!

I've found one lamp in garbage...And it works! :)

First radioamateurs played somehow like that. With resonant circuit (on the left, coil and variable capacitor) I'm receiving voltage, which can be seen on the oscilloscope.Lately, I rectified that signal, and directed it to LED.

Signal

Resonant circuit

Jacobs ladders

Time:

18.12.2005 11:00:59PM

Description:

Jacobs ladders are actually 2 wires in form like letter 'V', but NOT crossing.
If one wire is grouned and other connected to HF HV (high frequency, high voltage), than spark should go up, disappear, and start allover again (like in "Back to the future I").
As I have weak Tesla coil, I can't get some big sparks, and I can't that preceise put wires so that spark works like it should, so I've got something similar...
Sometimes I succeded to get right effect, but spark never wanted to go back...

Animation... one nice day I'll put it...

Pictures:

Schematic

Time:

27.3.2006 6:21:08PM

Description:

I remembered to put the schematic...

I "redrawed" schematic from site which can be now found maybe only in Google's cache.

If id doesn't run at first time, than you have to swap wires of the feedback coil. Than it should work.

It would be nice if the resonant frequency of the secondary is around 2 MHz (4MHz is some sort of limit...) or less because otherwise is very hard, or maybe expensive to get the required transistor for higher voltages and higher frequencyes. For now, BU508 (without D - builtin diode) showed like the best choice.

Diode on the feedback coil isn't necessary, but it makes transistor's life easier. (With it, transistor will be less hot).

I had problem with some coil that has 700 turns - circuit won't allways oscillate as it was supposed to. Only when I touched it, it gave me maximum power - but when I touched it again, it reduced it's power. I solved it with 750pF capacitor in parallel with feedback coil. So, if you have problem of that kind, you need to put that capacitor and play with it's value until you find the right one.

It's also good to play with number of the turns of primary coil and feedback coil. On that coil with 700 turns I have primary of 5 turns, and feedback of 9 turns.

Power supply can be from 12V to 24V, and maybe more, but transistor and resistor will then need some very good cooling system...

Schematics:

Schematic

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