We found this circuit in a 1964 Electronic Design. It divides the frequency of a 20 MHz signal by 2. The circuit uses a transistor from that time. Details of the coils were not given.
This circuit, from ancient French documentation, produces a rectangular pulse from input pulses...
This circuit uses only two general purpose transistors and can be powered by the circuit under...
This circuit, from a 1988 documentation, consists of an automatic temperature control using an NTC...