Principles of operation and a brief technical history
Are the basic principles as simple as those needed to understand the telegraph Not quite. To understand the telegraph all one needs to know is that electrical circuits may be switched ON and OFF and, in addition, one must be able to distinguish the symbols 1 and o from each other. In order to understand the basic principles underlying the operation of the telephone somewhat more is needed. One should, to start with, have some idea of the physical properties of sound. What are they By the middle...
Early attempts
The chances of sending a picture by telegraph very much improved with the invention of the electrical telegraph. It would have been, for Fig. 15.2 A possible solution for sending a fax by semaphore. Fig. 15.3 Schematic representation of the fax machine invented by Alexander Bain. Mechanism to lower or raise message block 1 There is an entry under Bain, Alexander in most encyclopaedias. He was a Scotsman who lived in the nineteenth century. Alas, the Alexander Bain of the encyclopaedias was a...
The transistor goes west
The first transistors were made of a semiconductor called germanium. It had the disadvantage that it could not work at high temperatures. Silicon, another semiconductor, was much more suitable for higher temperatures which inevitably occur in many devices but its technology was more demanding. Bell Laboratories were of course involved in trying to make silicon technology work. By this time Shockley was not there. He had a desk job at the Pentagon as an eminent civilian scientist but he was not...