This circuit can be used in measurement bridges. We found it in the September 1995 Electronics Now magazine. The meter can be from 50 uA to 1 mA and the power supply is simple.
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...