Using a CA3030, this circuit was found in the May 1988 Radio Electronics magazine. The power supply must be symmetrical.
Despite being from a 1969 publication, the transistors used have current equivalents such as BC548 and...
This interesting radio circuit for listening on a crystal phone was found in a Japanese magazine in...
This circuit is from a specialized documentation in 1992 FETs. The L1 coil has 0.07 uH with...