This circuit was found in an Electronic Experimenter Handbook from the 90's. The coil can be formed by 4 turns of wire 28 with 0.5 cm diameter without core for the FM band.
This circuit was found in a Philips documentation from 1970. The components are of the time,...
This circuit divides the frequency of a 2 kHz signal by 2. The circuit was found in Philips...
This circuit was found in an English publication. The components are current, and the transformer must be...