Using the 555 and 4020, this timer was found in the July 1994 Radio Electronics magazine. The relay is voltage-dependent, and the transistor is general purpose.
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...