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.
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