TRANSISTOR MUSEUM  

Historic Transistor Photo Gallery   

 

 

Transistor Size (1/2” Diameter X 1/4”H)

Date Code – None

Packaging - None

 

 

 

TRANSISTOR PRODUCTS INC. X-78

 

TYPE

Germanium Power

 

USAGE

Experimental/Developmental 

 

DATE INTRODUCED

1953/54

 

CASE STYLES

Epoxy Cylinder on Copper Heatsink

 

AVAILABILITY

Rare (Prototype – Limited Production)

 

HISTORIC NOTES

The earliest transistors were not capable of handling much power, and there was considerable effort across the newly emerging semiconductor industry to develop new types capable for higher power performance.  One of the earliest documented germanium power transistors was developed by a Harvard PhD graduate student, Neville Fletcher, who was on summer assignment at a small startup transistor company, Transistor Products Incorporated, in the summer of 1953.  His first experimental models were designated type X-78.  A sample is shown in the photo above. This model was a high performer for the time, listed as the only 1 Watt transistor in the 1956 “Transistor Handbook”, by William Bevitt (published by Prentice Hall).  The X-78 was manufactured in small quantities by Transistor Products Inc, which was acquired by Clevite in 1954.  Clevite continued to refine Fletcher’s original techniques and became a major manufacturer of germanium power transistors through the mid 1960s.  

 

 

 

 

Copyright © 2004 by Jack Ward

http://www.transistormuseum.com