We found this circuit in a 1976 documentation. The FET can be BF245 or MPF102 and the power supply need not be symmetrical. The FET in the feedback acts as an automatic gain control.
We found this circuit in a 2002 documentation. It still uses old type plugs, but it can be adapted to...
This circuit was proposed by a 1965 Electronic Design. Its purpose is to widen the line transients...
The circuit shown can measure currents less than 1 uA and is powered by two 1.5 V batteries in a...