This circuit uses an unusual operational amplifier nowadays and has a very low consumption. The number in parentheses corresponds to the second channel, for a stereo version.
This old circuit, from a 1992 documentation, was used with tape recorders acting as playback. The...
This band rejector filter, which uses the 741 again, prevents signals of a certain frequency, in...
This circuit was obtained in an old publication. The FET can also be the BF245. The potentiometers can be...