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 low drift or offset circuit is from an 80's documentation. The configuration can be made with...
This is a commercial circuit from a Japanese publication from 1972. The circuit uses a FET that...
This instrumentation amplifier was obtained from Popular Electronics in 1993. The operational...