[Milsurplus] How Much Vacuum in "Vacuum Tubes?"

[Gene Smar]

Gents:

     I recall fabbing a BJT transistor in lab in college (Lehigh U.)  IIRC, 
we used a small (1mm X 1mm X 4mm) bar of selenium and somehow fused indium 
balls onto either end.  Then we tried soldering to the three contacts and 
plugged the thing into a curve tracer.  What a disaster!  (This was the same 
lab where the 5VDC power supplies' variable output pots were locked with a 
locking nut to keep us from blowing the $5-a-copy IC logic gates that we 
also played with.)

     CU's at Timonium this weekend?

73 de
Gene Smar  AD3F


----- Original Message ----- 
From: "Jim Whartenby" <antqradio at sbcglobal.net>
To: <Milsurplus at mailman.qth.net>
Sent: Thursday, March 29, 2007 9:10 PM
Subject: Re: [Milsurplus] How Much Vacuum in "Vacuum Tubes?"


> Making a transistor should be much easier then making a vacuum tube.
> No vacuum pump or flames, just a steady hand, a microscope, a jig to
> hold everything and couple 1N34 diodes for parts should produce a point
> contact transistor.
>
> There was an article in the October, 1948 issue of "Radio and
> Television News" which gave step by step instructions.
> Point contact, anyone?
> Regards,
> Jim
>
>> Making tubes is certainly practical in a small facility. Not so for
>> transistors or ICs.
>>
>> -John
>
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