From ANDREW WYLIE
Jim Lesurf’s article, ‘The rise and fall of negative resistance’ (31
March) was most interesting. However, your readers should be aware that
it is not necessary to use an esoteric gallium arsenide Gunn-effect device
to observe this phenomenon. The first transistor ever made, Bardeen and
Brattain’s point-contact transistor, exhibited negative resistance. This
characteristic was exploited by the makers of early transistorised computers
because it was possible to make a bistable circuit (‘flip-flop’) using only
one transistor. Junction transistors do not possess this advantage.
Andrew Wylie London NW6
