This 100 Hz filter was found in the August 1993 issue of Electronics Now. The components can be modified to operate at other frequencies.
This circuit uses separate sources for the power supply and the operational stage. The output...
This is a MOSFET version of a grid dip meter for frequencies between 1.8 MHz and 150 MHz,...
Found in the March 1974 Radio Electronics magazine, this circuit is designed to measure the level...