This circuit of the 70's uses transistors of the time. The circuit can amplify signals from 10 Hz to 100 kHz and modern equivalent components can be used. The circuit is from Ferranti.
This sophisticated power supply for the laboratory of the maker or professional repaired was found...
The A3906 integrated circuit from Allegro MicroSystems (www.allegro.com) consists of a single-step motor...
This circuit for high power xenon lamps was found in the November 1974 issue of Radio Electronics...