This is the circuit of a commercial radio sold in Japan in the 1960s. The IF is 455 kHz, and the supply is made with a voltage of 9 V. The radio receives stations in the medium wave range.
This very simple circuit uses a phototransistor and a very sensitive relay (reed type) being used...
We found this circuit in Radio Electronics magazine from January 1958. It uses a neon lamp as the...
The integrated circuits in this application are not very common today. One consists of an A / D...