In the figure we have the way to obtain 500 gain from a FET. FETs can be BF245 or MPF102. The circuit is from the 1977 National Semiconductor FET Data Book. Power supply depends on the application.
This configuration has already been given in several articles and circuits on this website and...
This circuit is from a Harris Semiconductor datasheet from the 80s. However the circuit can be...
We found this logic level tester in a 1976 documentation. The circuit is powered by the voltage of the...