by Joe A. Knight




IBM began experimenting with transistors soon after the Bell Labs announcement in 1948 as they had recognized early on the potential for this new technology in their computer/calculator product line.  By 1950 they had begun fabrication of experimental point contact types for circuit design work. The real potential of junction transistors as circuit devices became evident to them by 1952. IBM's early transistor implementations were done using outside semiconductor sources, such as Texas Instruments.  By 1956 IBM was fabricating their own alloy junction transistors, as shown below.  The new "all-transistor"  IBM Model 608 computer released in late 1957 used all IBM manufactured transistors.




ABOVE, L-to-R:  The IBM blue Type 58 transistor was a junction type made in the 21st week of 1956.  The next black Type 58 was made in the 35th week of 1956.  The middle Type 51 was made in the 12th week of 1957, using the newer two piece soldered metal shell seen in the more common IBM types. The next Type 'H' is likely serial # 315.  The last device is an IBM Type 013 made in the 20th week of 1958. This tall enclosure is typical of all the IBM types made in 1958. The rubber band seen on many of this type was used to isolate the metal body from the circuit board, as they were usually positioned flat on the board plugged into their socket.










Go To IBM Early Power Transistors, Page 2


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Joe A. Knight Early Power Transistor History – IBM