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.
This is the traditional configuration of a differentiator with an operational amplifier. This was...
This amplifier circuit with a low power MOSFET was found in Popular Electronics from the 90s. The...
We found this circuit in Motorola's Circuit Applications for the Triac 1971 manual. The circuit is for ½...