I've been building a Tesla coil. I wanted to use a 3kV 30mA neon sign transformer but the problem is the length of the arc is not enough for my taste. Because of that I wanted to use a Marx generator to get higher voltage and huge amount of discharge voltage on its output.

So the question is,can I use a Marx generator for a Tesla coil. If can, do I need a spark gap to resonate the primary of my tesla coil?

BTW I need guidance I'm not a veteran on electronics.

  • \$\begingroup\$ Search this site. There are quite literally hundreds of questions and answers on Tesla coils (mainly asked by students and largely ignored by pro engineers). \$\endgroup\$
    – Andy aka
    Dec 11, 2019 at 10:29

2 Answers 2


Yes, 3kV is too low to power a Tesla coil.

A marx generator will get you the voltage, but that's only half the story of a good spark display, you need power to keep the arc channel hot and conducting, and to sound loud.

There's a more complicated but better way to use your meager 3kV transformer.

First, rectify your 3kV AC, which is about 4kV peak, through a pair of oppositely phased voltage doublers to +/- 8kV, or a total of 16kV bipolar. This is plenty to work with. You will still get good results with only a pair of halfwave rectifiers, to +/- 4kV.

Then use an inductor fed rotary spark gap to your coil, which will double the voltage yet again to your tank cap.

For details of that sort of coil, search for the specialist Tesla Coil sites like pupman for 'DC-fed rotary spark gap'. SO is a more general site and will not have the dedicated TC experts.

  • \$\begingroup\$ Thank you very much sir \$\endgroup\$ Dec 12, 2019 at 6:16
  • \$\begingroup\$ If I use a 10kv nst what is the peak dc voltage when rectified? \$\endgroup\$ Dec 13, 2019 at 3:56
  • \$\begingroup\$ Like all AC measurements, the nominal peak is 1.414 (sqrt(2)) times the nominal RMS, so 14kV. With NSTs, with their high inductive output impedance, you have to be careful into what load the nominal is specified. However, 10kV will give you a much better stab at a simple spark gap coil than 3kV. \$\endgroup\$
    – Neil_UK
    Dec 13, 2019 at 4:44

Danger Will Rogers.... This is a higher power grid powered arc. kW~

enter image description here

A Marx generator has higher impedance than the Tesla Generator, so it multiples by Cap chains, rather than transformer turns ratio and flyback inductance and extremely long ceramic bushings of low capacitance.

  • \$\begingroup\$ Thank you sir I appreciate it \$\endgroup\$ Dec 12, 2019 at 6:18

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