This Schmitt trigger in current mode for frequencies up to 50 MHz was found in a 1969 Motorola manual. Appropriate switching transistors can be used.
This circuit is from 2001 documentation, serving to multiplex stereo signals for FM transmitters. The...
This circuit reverses the signal if both positive and negative. We found it in an American...
Found in a publication by Gernsback from 1960, this circuit makes use of germanium transistors of the time....