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.
Obviously, it is a much more didactic setup than the one with great practical effect, but the idea...
We found this circuit in a 1983 English magazine, but it can be easily assembled with the BC548 or...
Maxim MAX25612 High Voltage LED Controller In stock from Mouser Electronics, this high voltage...