The FETs of this circuit can be the BF245. The circuit is from an old documentation and can be used in the amplification of infrasonic waves, of a sonic attack, for example.
This circuit was found in the November 1993 issue of Electronics Now magazine. The two-stage...
This circuit acts on a relay disconnecting the load when the input voltage exceeds the set limit....
This circuit is from a Radio Electronics from March 1970. The integrated circuit used is one of...