This filter is current driven and has the formulas given by the two diagram options. The circuit is from an American documentation from the 90s applying to any operational amplifier.
We found this 4-channel mixer in the August 1999 issue of Electronics Now magazine. The circuit can...
The configuration shown makes use of a simple source and the gain is given by the relationship between R3...
This circuit was found in a 1995 documentation and is very simple to assemble, as the components are...