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.
This circuit is from 1989 documentation. It uses the TDA2002 as a modulator and the unusual power...
This configuration is suggested by Mullard (Philips) in an old manual of 555 integrated circuits....
The figure shows how to use a CMOS amplifier as a crystal-controlled oscillator. The circuit is...