This circuit from a 1967 documentation generates 2.5 Hz signals depending on the capacitors used, in this case 160 uF. For 4 6700 pF the signal will be 20 kHz.
This flip-flop or bistable was found in a publication about transistors from the 60's. The circuit...
This preamplifier circuit for magnetic cartridges was found in the March 1986 Radio Electronics magazine....
This oscillator was found in a book on transistors from 1954. The transistor is from the time, and...