Re: Some interesting Nuvistor information


greenboxmaven
 

I read a history of them several months ago, but can not recall where I found it. The internal structure and envelope were manufactured in the atmosphere. The rim of the ceramic base was metalized so it would adhere to brazing. The components were then heated to outgas, then brazed closed, in a very high vacuum chamber. A getter was not used because the outgassing process cleaned the components very well. My experience has been that they are very long lived. The circuitry in consumer equipment may have also been designed so an aging Nuvistor would still give good performance, I have never seen any change in results from replacing a well aged one in a TV or FM receiver, even if they tested marginally. The low voltage version used in a Tek scope, however does get weak with time and can have catastropic effect on the operation of the scope.

Bruce Gentry, KA2IVY

On 6/17/20 10:00 AM, snapdiode via groups.io wrote:
I just think Nuvistors are cool. Any information on how they were made is interesting to me.
I've heard they were made in a high vacuum chamber with the assembly machinery in the vacuum chamber.
There is no exhaust port on a Nuvistor.
I also wonder if there is a getter in there, or if the metal case itself somehow acts as a getter.


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