TRANSISTOR MUSEUM™ Historic Transistor Photo Gallery
Transistor Size (7/16”OD X 1/2”H) Cardboard Package with Serial Number and Device Characteristics. Use this link for a detailed Type A Photo Essay: PhotoGallery Type A Page 2	BELL LABS TYPE A TYPE Germanium Point Contact USAGE First Developmental Transistor DATE INTRODUCED 1948 CASE STYLES Metal Cartridge AVAILABILITY Very Rare (Prototype)
HISTORIC NOTES According to Riordan and Hoddeson [1], a metal cartridge version of the original point contact transistor was developed at Bell Labs in the early months of 1948, only a few months after the invention of the transistor. This first cartridge version of the transistor was designated “Type A’, and represents the earliest developmental transistor which was robust enough to be manufactured in quantity (3700 by mid-1949) - many were made available (for experimentation and circuit development) to other companies, universities and the military. As shown in the photos above, each unit was serialized and the measured performance characteristics of the device were written on the cardboard packaging. Note the patent number (#2,432,116) printed on the package. This is not the original point contact transistor patent by Bardeen and Brattain, which is #2,524,035. The Bardeen/Brattain patent wasn’t filed until 6-17-49, so it seems that Bell Labs was forced to use an earlier, existing patent in an attempt to protect the newly discovered transistor. (#2,432,116 had been filed in 1943 and defined a method for making point contact diodes in a screw type base).
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