This 1960s Japanese 5-transistor radio is powered by 9 V and has good sensitivity for the medium wave range. The configuration is of the superheterodyne type with FI of 455 kHz.
Using an operational amplifier, the figure shows how to convert the waveform to low frequency...
This high quality circuit with complementary symmetry was found in an Electronics World of 1966....
This circuit was obtained in an old 1983 magazine, but it can still be easily assembled. The...