This circuit for the very low frequency range was found in the Radio Electronics magazine of February 1983. The components are according to the frequency range to be amplified.
This simple circuit with SCR and unijunction transistor appeared in Radio Electronics magazine in July...
Found in a 70s RCA manual, this circuit uses a transistor of the time for an UHF L band...
Found in American documentation, this circuit from the 90s uses components from that time. The...