TRANSISTOR MUSEUM™  

Historic Transistor Photo Gallery   

 

Transistor Size (1/4” Diameter X 1/4”H)

Standard T0-5 Case

Packaging - None

 

 

 

 

GE GLASS TRANSISTOR PROTOTYPE

 

TYPE

Germanium NPN

 Rate Grown Junction Transistor

 

USAGE

Experimental Packaging

 

DATE INTRODUCED

Mid 1950s

 

CASE STYLES

Transparent Glass

 

AVAILABILITY

Very Rare (Prototype)

 

HISTORIC NOTES

The first junction transistors from the early 1950s were primarily encapsulated in epoxy-type plastics, but this proved unreliable due to moisture penetration through the epoxy.  General Electric was an early leader in metal-cased transistors, and developed a reputation for high quality, rugged devices (see the 2N170 and the 2N107.)  However, metal cases were relatively expensive, so there was experimentation with less expensive glass packaging.  According to Carl David Todd, GE developed a glass-cased transistor prototype production line in the mid 1950s to evaluate the suitability of this approach for commercial devices.  Shown above are samples from this GE prototype work. These transparent glass cases have remained intact for the past 50 years, and the transistors are still functional. The white powder is a substance called molecular sieve, and was used to absorb moisture in lieu of the vacuum exhaust used in the old derby tophat form of GE metal can with the exhaust tube at the top.   Although thousands of these prototypes were developed (both NPN rate grown and PNP alloy junction), GE did not pursue this line in larger quantities, and never commercialized the glass case style - only a few specimens exist today.

 

 

Copyright © 2005 by Jack Ward.  All Rights Reserved.

http://www.transistormuseum.com