TRANSISTOR MUSEUM™ Historic Transistor Photo Gallery
Transistor Size (3/8”L X 5/32”W X 7/32”H) No Date Codes. No Packaging. Use this link for a detailed M1752 Photo Essay: PhotoGallery M1752 Page2 Note: These photos are high resolution and may require extended download time.	BELL LABS TYPE M1752 TYPE Germanium NPN Grown Junction USAGE First Developmental Junction Transistor DATE INTRODUCED 1951 CASE STYLES Black Epoxy AVAILABILITY Very Rare (Prototype)
HISTORIC NOTES William Shockley filed the original patent for the junction transistor on June 26, 1948, and it was issued, in part, as patent 2,569,347 on Sept 25, 1951. (See Proceedings of the IEEE, January 1996, p191-217). Work was done during this timeframe at Bell Labs to develop and refine junction transistor technology, with the result that a limited number of developmental junction units were produced. The initial model number for the developmental version of this transistor was M1752 – actual units were labeled with the handwritten text “M1752” or with the color-coded equivalent (violet, green, red). Units were also identified with a handwritten serial number. The two units shown in the photo above illustrate both identification techniques, with the serial number “DN335” shown on the reverse side of the unit marked “M1752”, and the serial number “EA926” on the reverse side of the color-coded unit. These units are very rare and represent the earliest efforts to manufacture functional germanium junction transistors. (The book, “Crystal Fire” by Riordan and Hoddeson, provides excellent coverage of this historic work at Bell Labs).
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