OBSERVATIONS FROM SCOTLAND 28 May 2008 GM1SXX
The Transistor hits 60!
Hailed by some as the most important single invention of the 20th Century, the humble transistor has it's 60th anniversary this month. I can't disagree, the transistor has revolutionised my life and that of everyone I know. Thanks to this invention and others, I can sit in front of my personal computer and see and talk with people around the world, something that still amazes me even now. I can also talk to anyone in the world who has a access to a telephone, thanks to a small lump of plastic and metal I carry around in my shirt pocket.
On the 16th December 1947, William Shockley, John Bardeen and Walter Brattain succeeded in building the first practical point-contact transistor at Bell labs in the USA. They were not the first to realise that the concept was feasible, Julian Edgar Lilienfeld in Germany already held several patents on ideas for field effect transistors, but Shockley, Brattain and Bardeen did indeed construct the first transistor device whose function could be demonstrated.
It wasn't very pretty, in fact, it was a rather mess, but it did work.
The transistor ended up being developed as a commercial product but initial take-up was slow. For the first few years, it seemed to stay as a lab curiosity. The first types were of the point-contact variety but these were followed by more familiar types such as the Bipolar Junction Transistor (BJT) and epitaxial types. The first radios to hit the marketplace using transistors were not a huge success.
Remember that battery driven valve technology allowed the construction of small self-contained table sets and the first generation of transistor receivers were really no lighter, some weighing in at a hefty 4 pounds.
I owned a marconi valve portable using the DK/DL series of directly heated valves and it was an excellent little radio. Until the Japanese produced much lower cost and smaller transistor radios, I never saw much use made of transistors in the UK. I first came face to face with a genuine transistor device in a little Japanese pocket radio set labelled 'Coronet'. The high quality plastic injection mouldings impressed me as much as the use of transistors.
The rise of Japan as an industrial nation and the reduction in size made possible by modern production methods led to the transistor radio becoming an affordable item although I don't seem to remember them being any more reliable than my old valve portable.
The first radio project I undertook with transistors was a six transistor super-regenerative radio using Philco transistors in the front end and top-hat types in the later stages. Somewhat surprisingly, many transistors of that era had no part numbers and I suspect that many of the ones that were available to Joe Public at considerable expense, were factory rejects! The Philco ones I used were encapsulated in two part metal cans joined by a horizontal seam. Rather attractive to look at in their shiny gold finish. The other 'top-hat' ones were in a two part can that looked like a top hat, usually black in colour. These were colour coded by a spot of paint. I believe the colours were related to the hfe figure. The radio was built in a plastic cabinet using point-to-point wiring on tag-strips epoxied in place. The HF tuning coils were wound of thin plastic covered wire wrapped on wooden dowels while the medium and LW ones were pre-made using Litz wire. The radio worked quite well despite its simplicity.
Many of the UK radios in that era used germanium transistors of the OC44, OC45, OC71 and OC81 types. These germanium devices were not the most reliable types and the change from germanium PNP to silicon NPN types was greeted with some relief, these being far more reliable than the germanium PNP types.
At one point I came by a large bundle of BC108's, so for quite a few years, the BC108 was my transistor of choice for every project I tried!
Somewhat interestingly, I have as much valve equipment as I do transistor stuff in the shack. I don't find keeping it working much of a bother either. Apart from a some hard to find valves, such as the 6JS6C and 7360, most valves are still easy to find. Still, transistors have crept in to my shack in my Racal RA1772 receiver and IC-730 HF Transceiver.
One thing is for sure, the humble transistor changed the world in a big way.
A few transistor links..
http://homepages.nildram.co.uk/~wylie/Mullard/Mullard.htm
http://en.wikipedia.org/wiki/Transistor#Bipolar_junction_transistor
http://www.pbs.org/transistor/background1/events/miraclemo.html
http://en.wikipedia.org/wiki/Point-contact_transistor
http://en.wikipedia.org/wiki/Julius_Edgar_Lilienfeld
Here's to the Transistor... and Shockley, Brattain and Bardeen!
I do suspect that the mobile phone might look a wee bit different, if it used valves. My FT817ND might also not be quite as dinky.
73 AL.
GM1SXX