This filter is from a 1977 publication. The circuit employs three 741 or other operational amplifiers. The supply must be symmetrical and the components with (*) are low tolerance.
The circuit we present was found in an English magazine from 1973. The complementary pair of power...
This circuit that equipped many transistor radios from the 50's was found in an American...
The circuit shown can be used on an infrared audio link. This circuit is from a Popular...