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 circuit can work with almost any JFET. The circuit is from an Electronics Now from April...
This physical line servo control uses components that are not currently common. The circuit is from...
This circuit was found in a British documentation from 1969. It can be implemented with modern...