An Interview with Carl David Todd

 Recollections from the First Days of Transistor Technology


Oral History – Carl David Todd (Continued)


More on the 2N107:

One of the customers, who had gone out and bought some (2N107s), was an engineer for a toy company, called Mattel, out on the West Coast.  And guess what he got - he got the “hot transistors” (those that were much higher hFE than the normal limit), and so he designed a circuit for a doll, using transistors to give it a voice.  They had designed and went into production – they sent in an order for 10,000 parts from GE, and of course, we sold them.  At the hobbyist level these weren’t much more than $1.00 apiece, and so I don’t know what he got for his 10,000 rate, but he got a pretty good price.


They started building these things, and, guess what, none of them worked.  They went to a zero yield, in producing these things.  I was in Applications at the time, as well as in Evaluation, so I got to talk to the guy. I said, “Send me your design, and I will see what I think may be the problem, and see if we can get your yield up”.  Well, he sent the design and according to my calculations, the transistors had to have a minimum hFE of 150 to 180, to even work.  And, it certainly wasn’t a designed circuit using the specifications of the part. I explained this to him and he said that he had gone down (to the distributor) and bought 10 of them and they all worked. I said, “You’re lucky!”  



Oral History – Carl David Todd (Continued)


I’m not sure what Marketing did about those 2N107s, but probably they accepted them back as credit against as order for some screened parts that didn’t quite meet normal voltage breakdown specs, but had a more uniform hFE.  I supplied the engineer with a more carefully designed circuit, and the yield increased substantially.            


As an electronics hobbyist, you wrote a number of transistor construction project articles for hobbyist magazines while you were working at GE.  Do you remember any of your very early transistor construction project articles?



“The Injecto-Cal”, Radio & Television News, August, 1956.



“Special Project – All Transistor Ham Rig”, Electronics Illustrated, Oct 1958.



“Designing a Telephone Amplifier”, Radio & Television News, July 1958.



“Metal Detector Finds Ducts and Pipes”, Electronics, August 1, 1957.





Go To Todd Oral History, Page 8




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