This indicator or logic probe was found in the April 1979 Radio Electronics magazine. The integrated circuit is the 555 and the FET can be any general-purpose type.
We found this circuit in an old 1980s documentation. The circuit can be implemented with modern...
This circuit is from a Linear datasheet. The circuit provides a 5 m voltage with 40 mA from an AA...
The components of this filter are calculated using conventional formulas (see mathematics section of...