Found in American documentation from the 1990s, this circuit uses coils with multiple outlets to get the best reception, the diode is a general-purpose crystal diode.
This circuit was found in a Popular Electronics from the 90s. The components admit equivalents and the...
The integrated circuit used in this amplifier is not common today. The circuit is from a...
The output of this circuit can be a crystal phone or a piezoelectric capsule. The circuit tests the...