The Turn Of The Century Electrotherapy Museum

Partially Rectifying Tesla Coil Outputs:
Point - Plane Collector Tests - 01. Sept. 2008

Polishing Plane Electrode - An Aluminum arc lamp knob from Brian Foley ...
Click here to see a movie!  

Sanding the 6" diameter copper collector sphere...

...followed by a bit of Brasso!

Before And After

A bit of spar urethane to keep them shiny.

The final collectors

Negative "Plane" Collector

Positive "Point" Collector

Test setup.  3.5kV 30mA Neon Sign Transformer, open core, unmodified.
2 Sangamo 2kV .1 mfd caps - in series - for 4kV .05mfd
Spark Gap - two series, 3/4" tungsten static gap - disk above shields light from gap

2 Pancake Coils in series, one with plane electrode and one with point electrode for discharge terminals

Collectors in place - Insulated with 3.5" OD PVC pipe - electrodes on pancake coils and collectors are just under 2" apart for this test.
Not sure what the ideal length will be!  These pipes were floating around the shop and seemed like a good start...

Left Pancake (with plane discharger) has pointed collector (for positive discharges)
Right Pancake (with point discharger) has plane collector (for negative discharges)

A simple crackle

Strange sparks when adjusting the spark gap length...

This is how they look up close.
A bit strange!

Note how sometimes the sparks appear jagged, or almost broken.

This is no trick - the sparks really look like that!

Just strange!

Click here for a movie

Correct:  Positive (with wire) to Negative - Note the color is consistent - blue/violet on left (positive), white on the right (negative)
Not exactly like a static machine, not exactly like a Tesla Coil!

Incorrect:  Negative (wth wire) to Positive - Note the difference in the spark appearance & color, and lack of intensity of the discharges

This was a lot of fun.  I can't wait to try some other experiments with this setup!