This Hall effect sensor circuit was found in the July 1998 issue of Electronics Now magazine. It is suitable for experiments with magnets in laboratories and schools.
In the figure we have a bistable multivibrator using an operational one. The circuit is from old...
This is another of the Star Trek red alert circuit that you can find on this site. We took this...
This circuit for testing zener diodes by lifting their curve on an oscilloscope was presented in...