This receiver was found in a Japanese publication in 1967. The circuit uses germanium transistors and details of the coils are not given. Power is supplied by a 9 V battery.
This bench circuit with no active components appeared in the August 1958 Radio Electronics...
The operational amplifier of this balanced circuit is old and can, however, be implemented with...
This circuit generates 5 notes in sequence, which are programmed in the connections of the 4017...