hazardjollyroger WARNING. The equipment on this page will try to kill you!

These impressive machines are used in high voltage labs to test equipment that is exposed to lightning. While full size ones can reach up to 60 ft in height, it is possible to build a small one and get some impressive results.

impulse edited-1

The impulse generator consists of a vertical stack of high voltage capacitors that are charged in parallel by a chain of high voltage resistors. We used 10 capacitors of 4.4nF and charging resistors of 3.3 megohm.

The capacitors are separated by spark gaps which when conducting, put them all into series. A small firing electrode is inserted in the bottom gap which causes it to break down and instantly fire all the others. As each capacitor is charged to 35 KVDC the resulting output pulse is around 350 KV. This jumps a gap of around 16 inches.

The output carries a lethal charge so an earthed ‘safety stick’ is used to discharge any remaining voltage.

Capacitor stack under construction using B&Q PVC decking trim.


Gaps being built in the same way. B&Q drawer knobs are perfect for this!


Charging resistors.


Finished unit with safety earth in place.


Lightning strikes my credit card. That will probably mean the chip doesn’t work now. :)

credit card