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Roger Riordan: Career

The Transistor

Part 1: Introduction

The Transistor

Part 2

The Transistor

Part 3

The Transistor

Part 4

The Transistor

Part 5

The Transistor

Part 6

The Transistor

Summary

OC139 npn transistor (envelope removed) & prototype circuit

~1958. (The objects with red & yellow tops are similar transistors)

From 1951 to 1954 I studied Electrical Engineering at Melbourne University. For the previous 40 years Electronics (which was my primary interest) had been almost exclusively about vacuum tube (valve) amplifiers. These had been invented by Lee de Forest in 1908, and were basically incandescent lamps with a couple of added electrodes. They were expensive, fragile, and inefficient.

The 1939-45 war had started a period of rapid change, particularly in the field of radar, but it hadn't reached our course.

The first computers had been built for the US Bureau of Statistics, but they had to use vacuum tubes, so were exceedingly large, expensive and unreliable. By modern standards they were also exceedingly slow. They were mentioned in our course, but no one suggested we would ever have anything to do with them.

The first major advance was the invention of the point contact transistor in 1947 by John Bardeen and Walter Brattain, followed in 1952 by the invention byWilliam Shockley of the junction transistor. The improvements in materials technology which made these inventions possible also made it possible to produce reliable junction diodes, which soon replaced the expensive and very inefficient metal oxide rectifiers formerly used for low voltage rectification.

In our final year we had just one lecture on these newfangled semiconductors, and one student had an OC71 germanium junction transistor (which I think cost several weeks wages) for his final year project. I was very interested in this whole field, so I did my own research and wrote an article describing the transistor, which was published in the Melbourne University Engineering Students Club magazine, Cranks and Nuts, in 1954.

This article is reproduced below.

 © Roger Riordan 2004-2017

The Transistor Introduction