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.
R1 may be 10k and R2 100k. The transistor can be the BC548 and instead of the small lamp we can...
We find in a Radio Electronics of the 90s this low noise amplifier that makes use of an uncommon...
This circuit show the performance of a GraetzBridge or Diode Bridge usedin full-wave rectifers....