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Re: Hydrogen diodes!!!??


From: 	Richard Wayne Wall[SMTP:rwall-at-ix-dot-netcom-dot-com]
Sent: 	Saturday, September 06, 1997 3:28 PM
To: 	Tesla List
Subject: 	Re: Hydrogen diodes!!!??

RH wrote: 

>Well during the long trip to NY, Kim, Dave and I mulled over the issue 
>of back to back timed H2 thyratrons.  I advanced that a simple mercury 
>vapor diode (866) in reverse would at least allow for one reversal in 
>the primary circuit.  All of us thought that a capital idea.
>
>On returning and consulting the data sheets, I was dismayed to find 
>that the standard Hg vapor diode needs a horrendous 8-10usec to fully 
>ionize!!! (~1000usec to click off)  Unfortunately, it's all over but 
>th' shoutin' by the time the darned merc gets goin'.

Richard it's simple enough to give it a quick go.  Don't be put off by 
just a few specs.  Sometimes new discoveries are made when they're 
least expected.  The delay will probably change the harmonic content of 
the waveform.  It could be beneficial.  Who knows until it's tried?  
Since 866As have a max PIV of ~10 kV, you will probably need a couple 
in series.

>Hydrogen diodes (100nsec click on time) are available, but are about 
>1000 times rarer (surplus) than the average H2 thyratron!  

But, they are out there, if you look for them.  I just picked up two 
1B45s very cheap at SkyCraft.  They are Argon-Hydrogen spark gap 
diodes.  They conduct at 2.7 kV and 450 A.  All these vacuum tube 
diodes begin with 1B.  (See "Tube Lore") 

snip

> Lots more to this than meets the first blush conceptualization.  
>Still, I will endeavor to vary the effective primary circuit on time 
>electronically.

I concur.  Currently, I am trying to directly base drive a resonator.  
I am trying to totally eliminate the primary and secondary of the 
driver.  The driver is a direct current vacuum tube driver.  The trick 
is to switch the base to ground circuit off, fire the driving pulse, 
then immediately switch the base ground circuit back on.  As you can 
imagine, timing is critical, as well as, rise time, frequency and 
harmonic content of the driving pulse.

RWW