How To: Give Your Jacob's Ladder More Spark with High-Voltage Capacitors

Give Your Jacob's Ladder More Spark with High-Voltage Capacitors

Here's a simple and easy addition to your own Jacob's Ladder. If you don't have one, here's how to make a Jacob's ladder.

All you need is a couple high-voltage 15KV capacitors connected in series to each of the ladder's prongs. Basically, rather than arcing right away, the high voltage transformer charges up the capacitors. Then, once they reach the "arc threshold", the capacitors discharge across the Jacob's ladder arc-guides, creating a loud, violent spark. This process happens several times a second, creating bright flashes of light.

Here's a video of it in action (the two gray "blobs" at the bottom of the ladder are the capacitors attached in series with the transformer output and ladder prongs):


  • High voltage is dangerous! Be careful.
  • Always make sure to discharge capacitors after use! They can hold a charge and shock you.
  • I am not responsible for any damage or harm you cause. 

It’s Black Friday week on WonderHowTo! Don’t miss out on all of the big sales in the Gadget Hacks and Null Byte shops. And if you’ve been wanting to take some classes without going into debt, check out our best deals on online courses for a variety of skill sets. Don’t miss out on these huge discounts:

See Gadget Hacks’s top 10 BF sales on online courses (up to 99% off) >

See Null Byte’s top 13 BF sales on online courses (up to 99% off) >

Photo by Wikipedia 

Our Best Phone Hacks

Gadget Hacks' tips — delivered daily.


Super cool! I just got an old tv off the side of the road. Mad Science will definitely be doing some high voltage stuff! Thanks Christopher!

Have you tried putting the capacitors in parallel i.e. in parallel with each other, and then that pair in series with the HT? Two identical capacitors in series have half the capacitance, in parallel they have double the capacitance. So putting them in parallel should deliver 4 times more power (but will take 4 times as long to charge).

I considered that, but those capacitors were only rated at 7kv, and my transformer output is around 13kv. so by putting them in series, I was able to handle the output power of my transformer.

Share Your Thoughts

  • Hot
  • Latest