This circuit by Ferranti, in a 1967 publication, is intended for reading perforated tapes. The circuit uses transistors from the era that can be replaced by modern equivalents.
This beat frequency oscillator for receivers was found in a documentation for radio amateurs from...
This 6V regulator with FET was found in an old Electronic Design. FET and transistor admit modern...
This amplifier for hearing aid was found in a 1968 documentation using an integrated of the time....