This circuit for very long-time intervals was found in the March 1993 Radio Electronics magazine. Times of several days or even weeks can be achieved depending on the value of C1.
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...