This Linear Technology circuit can measure currents from 100 pA to 100 uA. The circuit is from the 80's, using a component of the era. Transistors are general purpose types.
This circuit was found in Electronics Now. With it the dialing signals of a telephone are...
This circuit switches the brightness of the LED. We found it in an English documentation....
This circuit already explored in several diagrams in this section was found in a 90’s Popular...