This circuit with the PA7601 was found in a 1967 Philco-Ford documentation. The circuit has a pass band from 45 to 120 MHz.
This sensor circuit for currents of the order of nanoamperes was found in an American...
This circuit is from a manual of FETs of 1977. The FET can be the BF245 or MPF102 and the relay is of...
This configuration similar to many of this site was found in 1965 General Electric documentation. Modern...