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 obtained from an English magazine from 1977. The magazine no longer exists, but...
Found in a 90s Radio Electronics this circuit requires precision resistors in the dividing...
This circuit consists of a pre-amplifier for high impedance microphones. The circuit uses a FET...