This old 1967 audio preamp uses germanium transistors. It was found in Japanese documentation at the time and has a gain of 70 dB, being powered by p V. The input sensitivity is only 12 mV.
Found in a November 1977 Radio Electronics magazine, this digital circuit was described in an...
This powerful transmitter for the 27 MHz band was found in a Japanese publication from 1961. The...
This circuit was found in Radio Electronics magazine from April 1961. The device has a slot for...