Project Thumper is one of the Group's most well known demonstrations. Thumper is a massive impulse generator that shakes the building to its foundations and creates a brilliant explosion when it goes off. It's one of the two most requested demos we have and a surefire crowd pleaser every time we use it in a class.

Thumper is a High Energy DC Impulse Generator that is capable of producing a 1,800 Volt discharge of approximately 80,000 Amps for a duration of about 0.003 seconds. For a brief instant Thumper can output roughly 144,000,000 Watts, or more energy than most fair sized cities use at any given moment.

Imagine that for a second. Take all of the electricity in every home, business, school, hospital, everything in your entire town....and run it through a pop can for just an instant.

The capacitor storage banks are configurable for different voltage ratings, current ratings, and discharge times when needed. This is the standard 1,800VDC configuration that it was designed for and how it is usually operated as it's a pain to change all the bank and cell jumpers. We operate Thumper at the 1,800 volt setting, but only charge it to 1,600 volts to be as nice to the caps as we can be as this is a particularly harsh use for them (usually directly into a crowbar type load with the risk of serious reversal).

Thumper was designed by Chris Boden and Mark Broker and built by over 20 different Geek Group members over its long development cycle. Thumper has been through 8 major prototypical stages and is constantly being improved upon and upgraded. Despite the fact that it has been a perfectly functioning demonstration and research piece for several years, we don't anticipate calling it "finished" until about 2010 or so.

The original idea for Thumper was conceived in late 2000 while the Group was working at the Sigma-6 Labs. We had a long working relationship with Cornell Dubilier because of the MMC caps for our Tesla Coil projects and while talking to the engineers at CDE the idea of building a massive array of DC Electrolytic caps was kicked around. They thought it would be interesting to see and we were always looking for another project to tinker with so they agreed to send us a few caps to play with.

A couple weeks later a pallet of brand new Inverter Grade 2000uF 450VDC caps arrived packed neatly into boxes of 20.

Here's one up close.

We of course could not just leave them to sit in the storage room while we sourced the other parts for the array. If you have a ton of shiny new caps, you simply *have* to do something cool with them.

So we stacked them to the ceiling in the hallway.

Hey, some guys stack beer cans in the hallway of their dorm room, we're Geeks, we stack capacitors.

In late May of 2001 Mark Broker and his assistant (a high school student named Chris) worked well into the night to hand assemble what would become the massive Project Thumper. The following pages will take you through each stage of it's evolution and design all the way to the beautiful machine it is today.