This astable multivibrator was obtained from a Mullard documentation from 1960. The components depend on the used transistor and on the frequency, as shown in the table next to the diagram.
This low power circuit for the FM band was found in a spy book from the 90s. The tunnel diode is...
Obtained in a 1968 Electronics World, this circuit uses transistors from the time and the sensor...
The basis of this circuit is a CA3130 operational amplifier. The transistor can be BC548, and the...