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.
Recommended by 90s a Radio Electronics, this unit uses a transformer with a 70 V x 5 A secondary,...
This high voltage regulator uses only two passive components. The output is 100 V, but replacing...
This circuit detects magnetic fields by approximation, using a Hall sensor. The components are...