D.D. McBride


Oral History – D. D. McBride



2) The strips were then cut into pieces about 1/8” wide.  The next task was to actually make the shape of the points at the end of the strips, but first I would drill holes in each end of the fiber where the strips attached to the fiber so that the header leads could be inserted and soldered to the points. 

3) We would then do cutting and shaping of the points in the same operation. I’d use a microscope and cut, by hand, each point to the correct shape and also make sure that the ends of the strips where attached to the fiber were separated.

4) I’d clean the headers and then bend and form to fit the points.  I’d cut the header leads and shape the base lead into a small circle to fit the heat sink base that the germanium wafer was mounted on.   Next, I’d etch and clean all the material to get ready for final assembly.

5) Finally, I’d mount (solder) the base and point contacts in place. Under a microscope, I’d adjust the points on top of the germanium wafer to about 5 mils apart. We’d use LePage cement to hold the points in place. Once dried, we canned the transistors in oil for heat sink purposes.


Personal Recollections About The TI Point Contact Transistor Program


After serving for almost four years during WWII in the South Pacific, I returned home to Matador, Texas in September, 1945.  I got advice to get training as a certified watchmaker, which I did.  In Dallas,  I


    McBride Oral History, Page 3



Oral History – D. D. McBride




This photo shows the two types of point contact transistors that were manufactured by Texas Instruments.  The transistor on the left is the earlier type.  It uses a cartridge style case and is similar to the units made by Bell Labs and Western Electric in the early 1950s.  The plastic band encircling the cylindrical case actually covers a circular hole in the case that allowed the two point contacts to be physically adjusted for best performance during manufacture.  This type was sold by TI as model numbers 100 and 101, but was discontinued in April 1953 because of the manufacturing difficulties inherent with this design.   The unit on the right is the style described and built at TI by “Mac” McBride.  It was sold by TI as model numbers 102 and 103, starting in September 1953, and was advertised as “hermetically sealed”.   This unit is 5/16” wide by 7/16” high.  Inside this metal case is a horizontally mounted fiber strip that anchors the two point contacts, as described in the text.  “Mac” recollects that the cartridge style had been discontinued by the time he started to work at TI, and he began his job by building the type shown on the right in the above photo.   





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