Re: [ATM] Aging atm's (1950's)

[Chris Rowland <chris_group_mail@dsl.pipex.com>]

Bob May wrote:
 > Never heard of a glass transistor either.

I think he means a valve :-)

 >  Early transistors were made from
 > geranium (not the plant!) and were encased in metal tubes although 
the bases
 > of those tubes were a glass seal..

Its Germanium.  The OC71 transistor was in a glass tube with the wires 
all coming out of one end. The black paint could be scraped off to give 
a photo transistor.  I remember making a light beam telephone with the 
transmitter a light bulb with the current modulated by voice signal. 
This was long before the LED was invented, so don't suggest that I 
should have used one :-)

 >  Diodes of the time tho were encased
 > often in little glass tubes that were sealed to the leads on the ends.
 > I'll note that the first integrated circuits were done on flat panels of
 > metal with pins stickin gup through the metal and sealed with glass. 
  A hat
 > shaped cap was then placed on top of the metal and brazed together.

I hear the inventor of the IC has recently died.

Chris


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