This crystal or galena radio is one of the many versions available on this website. This is from a documentation from the 70s. The coil is formed by 50 + 50 turns of wire 28 in a ferrite rod.
The original frequency of the Pierce Oscillator with bipolar transistor is given by the crystal, which...
Of course, the design indicates a specific application for a touch switch. Thus, analyzing the...
This circuit converts signals from the 350 to 500 kHz band to the 4.36 to 4.5 MHz band, enabling...