[Milsurplus] EN91 / 2D21 / CV797 xenon filled shield-grid thyratron.

[J Forster]

A pair of 2050s, slightly bigger than the 2D21, was used in the ADF
add-on unit for the MN-26 Radio Compass  (the MN-31). They were used as
phase controlled rectifiers to drive the "football" loop the proper
direction to null.

They were also used in small, separately excited,  DC motor speed
controls in the 50s and early 60s, until they were replaced by SCRs and
later TRIACs.

In the IBM 709 computer, a 50s vintage tube monster, there were banks of
them. I think they were relay or solenoid drivers. I do know about once
a week there were baskets full put in the trash by the IBM CE. That was
when computer time was $600 an hour.....  and remember $500 would
roughly buy you a VW Beetle.

Best,
-John

======================

WA5CAB at cs.com wrote:

> The 2D21 is normally or sometimes (weasel word) used as a grid
> controlled rectifier.  I can't recall what they are right now but I'm
> sure I've run into a couple of sets that used them in the power
> supply.
>
> In a message dated 11/11/2008 4:34:16 PM Central Standard Time,
> Military1944 at aol.com writes:
>
>> While sorting out some valves with a view to reducing the stock here
>> I found a box marked CV797, which turns out to be an EN91 / 2D21 /
>> CV797 xenon filled shield-grid thyratron.
>>
>> Now, what on earth can I use it for ?  Any ideas.
>>
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
>
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