This circuit was found in the December 1992 issue of Radio Electronics magazine. The current is a few mA and the maximum input voltage is around 12 V.
We have here a very interesting project found in a 1982 publication. By the operation of the...
We found this circuit in an old American manual. The formulas allow the gain to be calculated as a...
This circuit is from the time when cars used contact breakers. This 80's version measures the dwell...