EARLY TRANSISTOR HISTORY AT BELL LABS

An Interview with Homer Coonce

 Early Transistor Digital Logic - Flyable TRADIC to Nike Zeus

 

Oral History – Homer Coonce

(Continued)

 

When did you begin working with transistors?

 

My first experience with transistors was on one of my rotational assignments during my first year at BTL.  Jim Ebers was my supervisor.  One of my jobs was to measure charge storage time of various diodes and transistors and plot the data for different current levels. This work was directed by Dr. John Moll.  The main effort of Eber's group was to develop junction transistors.  When experimental devices were removed from the ovens the entire group would gather around a curve tracer to view the junction sharpness, breakdown voltage, etc.  It was very exciting.  Everyone was looking for a major breakthrough at any moment.  I was given some germanium chips and various types of wire so I could try making my own transistor.  I positioned wires on opposite sides of the chip and passed a controlled current through the wires to fuse junctions at the wire contact points.  I still have a crude transistor I made using that procedure ---not a very good one I must admit. (Curator’s Note: See page 1 of this Oral History for a picture of the transistor that Homer crafted.  Note that the first junction transistors had been fabricated at Bell Labs in 1951, based on Shockley’s pn junction theory developed in 1949.  Homer’s 1952 transistor is indeed a very early and historic example of junction transistor technology).

 

 

 

 

 

 

 

Oral History – Homer Coonce

(Continued)

 

What was your involvement with the Flyable TRADIC?

 

Early in the design of the TRADIC flyable model my supervisor told me that I was the "circuit pack expert"!  I didn't do the original design, but as the project progressed it was my job to make modifications as required to optimize circuit performance.  I also made several emergency overnight train trips to Greensboro, NC to solve production problems.  The packs were manufactured in the Western Electric plant in Greensboro. 

 

Another of my responsibilities was to install and tune resonant circuits in each equipment cabinet to maintain the correct phase relationship among the four phases of the one megahertz clock.

 

Point contact transistors were somewhat unpredictable, not well understood, and didn't lend themselves to detailed circuit analysis.  A jet of cold air was directed to each transistor in the system to prevent lock-up.  Transistor lockup caused the pulse transformer to overheat, explode, and blow a hole in the circuit pack.  The packs were encapsulated and could not be repaired except for transistor replacement.  Transistors were not included in the encapsulation.

 

 

 

Go To Coonce Oral History, Pg 3

 

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