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 with two operating modes was found in the September 1989 issue of Radio Electronics...
This circuit was suggested by old French documentation, but it can be used as a shield, in which...
This well-crafted speed game setup for two competitors was found in a 1998 Poptronics. The circuit...