This circuit was obtained in a 1970 EEE and applies to almost any operational amplifier. The supply voltage depends on the operational amplifiers used.
This circuit for PC and which can also be used with microcontrollers was found in an English...
This two-tone decoder has a bandwidth of 24%. The circuit is from a 1994 Electronics Now. The...
The LMV321 is a low voltage operational amplifier from ON Semiconductor. The following diagram,...