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.
We found this complementary simetry configuration in a1980s documentation. Transistors, which are...
This circuit was obtained from the May 1971 issue of Radio Electronics magazine and is intended for...
This circuit acts as a VU-meter when connected at the output of any audio amplifier, triggering a...