EARLY TRANSISTOR HISTORY AT RCA

Gerald B. Herzog – First Transistor Television

Oral History – (Continued)

 

 

As I was saying in the previous section,  finding transistors that would drive half an amp  of current into the yoke and withstand the several hundred volts flyback voltage was very difficult.  Some transistors were being made in those days that were in cans filled with toluene.  I selected many of these, put them on the curve tracer and ran the collector voltage out to where they broke down. As the toluene boiled, the collector breakdown voltage would seem to walk out, and if they didn’t blow up before I found a high enough voltage unit, I had one that I could use in my transistor set.   I would run back to my own lab and plug it into the circuit, and I would be able to drive the yoke.  Eventually we found enough units that I had two superior units that worked in the TV set for the rest of the time and were still good during the entire demonstration.

 

There was still a major problem however, even though I had units that would drive the full deflection for a five inch kinescope. There was so much storage time in the power transistors, that just by using the TV sync signal to drive the circuitry caused the sync period to end up in the middle of the picture – we had a black bar down the middle of the screen.  The planned demonstration of the TV set and all the other devices being built at the laboratory with transistors was just a few days away, and we had no decent picture to show. 

 

 

 

 

Go To Herzog Oral History, Page 11

 

 

 

 

 

 

       

Photo Courtesy Bob McGarrah

This is a macro photograph of the TA165/166 style germanium point contact transistor mentioned by Jerry on the previous page of this Oral History.  RCA began manufacture of these developmental (pre-production) transistors at the Harrison NJ Tube facility in a group led by Bob Slade in 1951.  For several years after the invention of the transistor (late 1947 at Bell Labs), the point contact technology was all that was available, and even when junction units began to appear in 1951, the point contact units were still needed for any application above audio. Jerry used these point contact units in the RF/IF sections of the TV.   It must have been a challenge to find a sufficient number of working and stable TA165/166 units for the TV, since the point contact technology was notoriously erratic and sensitive to physical shock.  Note the two small metal point contacts pressed against the germanium block in the center of the photo.    The entire unit is encased in epoxy and is approximately 3/8 inch in height.  

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