This interesting circuit was found in a 1968 documentation. The transistor can be a general-purpose equivalent. The circuit can act as a shield.
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,...