This high voltage source, found in 90’s Popular Electronics, can reach tens of thousands of volts. The Q2 transistor must have an excellent heat sink and the 9 V source is high current.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...