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 an American 1980s documentation. The circuit can be digitally programmed...
This circuit was suggested by Texas Instruments in a 1980s documentation. The transistor must be...
This circuit was obtained in a manual of the used old operational amplifier. However, the same...