Mystery Tube at The Radio Technology Museum
Last Update - 1 MAY 2017

	This arrived in a donation of random vacuum tubes from an estate. 4-pin base is engraved 201A
	A heavy spiral filament sits insice a shield. Neither touch the triangular metal prism. My small bench supply gave up at 1 volt at 1 amp without causing any glow.
Only two wires come through the press. They connect the filament to pins 1 and 4.
	Shows gas when activated by a Lepel high-frequency coil (baby Tesla).
Operational Tests 1 MAY 2017

	Filament draws 2.5 A at 6.3 V (Not much anode current at 5 V.)	Filament is on the right in all pictures.	Anode draws 3.3 mA at 400 VDC
	Pictures were taken in auto-exposure mode, and were post processed with Faststone Image Viewer.  The above have the "highlights" adjusted all the way down.
	In an attempt to accentuate the image of the discharge, I further reduced the highlights, so the stratification of the blue is an artificact of the image processing.
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