The purpose of this circuit is to cut off the high voltage when the bias voltage fails. The circuit is from a 1975 documentation and can be adapted for other purposes.
This 3V-only circuit was found in old American documentation, but can be implemented with...
The output voltage of this circuit, which can regulate the current in a load between 0 and 1 A,...
This circuit was found in a Popular Electronics from the 90s. The circuit has temperature...