We found this circuit in a 1968 Electronics World. The circuit uses a transistor of the time providing a 16 dB signal gain with a 4 V output.
This sophisticated circuit with a low, medium, and high treble filter is from 1990 documentation. The...
This power supply was found in a RCA publication from the 1970s. The circuit uses transistors from that...
Placed near a telegraphic transmitter (CW) and with a small antenna or pickup, it reproduces the...