This circuit is suitable for use in radio receivers to improve the quality of weak signal stations. The circuit was suggested by the May 1994 issue of Electronics Now magazine.
This circuit was found in a 1980s documentation. Modern general purpose transistors can be used....
Found in a 90’s Popular Electronics, this circuit uses a component that can be difficult to obtain...
Suggested by Fairchild in a 1980s publication, this multiplier uses operational amplifiers from that...