This circuit was taken from an old American documentation. It can be built with modern op amps. The power supply does not have to be symmetrical.
This circuit separates the bass from the treble in an audio signal. The circuit is from a Hands On...
This circuit was obtained in a 1986 documentation consisting of an active frequency divider for...
We found this circuit in a Popular Electronics from 1992. It consists of a voice scrambler used in...