Found in a 303 Circuits from the 90's this circuit can use the lowest current range of a common multimeter. The circuit can measure currents as low as 100 pA.
This circuit came out in an American magazine that no longer exists. It's the Electronic...
This circuit originally came out in a Budget Electronics from 1981. The American magazine no...
This is the traditional audio preamp configuration with the National Semiconductor LM382. The...