02.08.2014, 11:59 AM
Zitat:Original geschrieben von kahlo
Eine Erhöhung der Kapazität im Primärkreis ist solange super, wie der Oszillator oszilliert.
That's correct. Oscillation is started by the diac when DC is high enough and enough current is drawn across the transistors.
Increasing the capacity over the bridge leads to an increase in DC RMS due to ripple being filtered. If the DC is high enough, oscillation continues without the help of the diac, which stays disconnected.
This basically means that you can add a regulator to regulate DC and therefore get regulated (always the same) AC at the output. By doing so, you will drastically filter any 100Hz ripple and the resulting ouput will be virtually pure HF AC at the oscillation frequency (usually between 40 and 60kHz.
The only case when oscillation is not going to happen is a no-load condition. This is what the diodes in parallel with the transistors are for: no-load protection circuitry.