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.
September 2016 - can already be purchased at Mouser Electronics the Robot Scribbler S3 from...
This circuit is suggested by General Electric in 1966 documentation. The Triac must match the...
This circuit was found in Radio Electronics from the 90s. The circuit employs a transconductance device and...