EARLY TRANSISTOR HISTORY AT RCA Norman H. Ditrick Oral History – Continued
This is a photo of an experimental transistor radio constructed by Norm Ditrick in the mid 1950s. It uses six various prototype transistors, none with production markings. You can see two of the three high frequency types in the center right of the photo, directly underneath the red wire – these white cylinders are 2N139/2N140 prototypes. The three AF units are located at the left center, again by the red wire. The larger silver units with yellow paint dots are 2N270 style power output devices and the black cylinder with the red dot on top is a prototype 2N109. According to Norm, the radio is still functional!	The scan shown above is a section of a memo from Apr15, 1952 that indicates quite clearly the model numbers of some very early developmental transistors (identified as TA types) which had been constructed at the RCA Harrison facility. Both point contact and junction types are shown. In the far right column are the initials of the engineers who were assigned to each of the transistor types. Note that Norm Ditrick was assigned the TA196 and TA209 junction types. The Oral Histories of Rob Kleppinger and Fred Hunter are available directly on the web at the transistor museum. ______________
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