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.
April 2017 - The new Maxim Integrated MAX20733 and 20745 switched regulators are available from...
The indicator for this circuit is a mini buzzer with a 1.5 V oscillator. The circuit can also be...
This 80's documentation circuit includes an amplifier of the era. Used integrated circuits are...