We found this circuit in a Poptronics from the 90's. Equivalent operational amplifiers can be used. The circuit must be supplied by a symmetrical source.
This is another of the Star Trek red alert circuit that you can find on this site. We took this...
Found in American documentation from the 1980s, this circuit is a basic signal rejection filter...
This circuit can be used in physics experiments, in ionization and in several other applications. The...