This oscillator uses a small IF transformer taken from an old transistor radio. FET admits equivalents. The circuit can be used to calibrate radios.
In the figure we have the adapter circuit for connecting a headphone to the output of a stereo...
Found in the June 1972 issue of Radio Electronics magazine, this circuit generates signals that...
The output of this circuit must be connected to the input of an audio amplifier. The microphone is a small...