[Alex Kitic]

Zitat:Original geschrieben von kahlo
Dann entlädt sich die vergrösserte Primärkapazität über einen Transistor. Der Transistor brennt durch.

Two conditions for burning a transistor:
1) over-voltage: the peak voltage remains the same and the transistors are chosen with the peak voltage in mind.
2) over-current: a short circuit, or too high load - both taken care by the short circuit protection if one is fitted in the unit.

In reality, the only way to burn the output transistors is too high load (overheating, which is why I mentioned the DC current issue on the voltage doubler B+ circuitry), or maybe using a highly inductive or capacitative load that would destabilize the transistors (which I did not consider in detail since my primary aim is direct heated cathode tubes, where the filament is a purely resistive load similar to a light bulb).

In a way, the filamentary cathode of the 813 is a 50W (10V 5A) light bulb.