Dave said:
Could anybody with a copy of towers etc. give me an equivalent for a 2N3904
That part can probably be accurately described as a "jellybean" - it's
an NPN switching transistor, Ft 300 MHz, good up to an absolute limit
of 40 volts and 200 mA.
They're quite common and easy to come by, I believe. If you can't
find one, then unless there's something exotic about your application
you can probably substitute a PN2222A. 2N4401 might also work (Ft is
a bit lower), and I have no doubt that there are a zillion other
substitutes which would work OK in many circuit applications.