This 100 Hz filter was found in the August 1993 issue of Electronics Now. The components can be modified to operate at other frequencies.
Based on Radio Shack 276-137, this circuit was found in the December 1995 issue of Electronics Now magazine....
This circuit provides a good audio power from a signal at least 1 V of amplitude. The MOSFET must...
Suggested by an old American documentation the circuit below keeps a battery charged and at the...