The Turn Of The Century Electrotherapy Museum
(C) Jeff Behary 2007

1.25" Inch Diameter Tungsten Mounted to 6" Diameter Aluminum
Quenched Spark Gap
Inspired by Thomas Stanley Curtis

Updated:  06 Sept 2007

This gap was tested with a 1920s twin pancake Tesla X-Ray coil using a 1000V 1500mA transformer and .6 mfd capacitor.
The coil performed its best to date. 

Click here for a video of this coil in operation with the quenched gap seen below.

Side view of finished gap.  Many thanks to Brian Foley for the red hexagonal insulators!
To the right can be seen some gaps "in the works".  (Tungsten rotating anode, 3/4" diameter tungsten finned gaps, contacts, etc.)

Top view.  By turning the hexagonal knob the distance of one full flat of the hex, the gap can be adjusted by 9 1/4 thousands of an inch.
(The top gap is threaded 5/16-18)

Here is a side view of the gap in preparation for the next photo...

Here is a close view of the gap itself, between parallel faces of 1.25" diameter tungsten contacts.

Side view of gap.  1 1/4" Tungsten Contacts are mounted to the top of the bottom plate and the bottom
of the round heat sink assembly.

The base is 6.5" square x 1/4" thick aluminum.  The bridge is 1/8" thick copper 2" wide.

Two tensioning supports are made from elevator bolts and springs...

A closeup view of the contacts.

Quick snap of gap in operation.

When quenched gaps are used normally the discharge length of the coil shortens but the temperature of the discharge increases.

Click here for a movie!

They are well suited to handle the full current of a microwave oven transformer with only one single spark gap.