We found this circuit in the July 1969 Radio Electronics magazine. The circuit uses a coupler made with a lamp and an LDR. The power of the lamp determines the types of diodes.
This oscillator takes advantage of the 2000 ohms headphone inductance as the oscillator circuit coil....
This circuit, in addition to providing an output that corresponds to the absolute value of the...
This circuit works with the previous two by demodulating the signals received modulated in FM. The...