03.08.2014, 01:10 PM
Zitat:Original geschrieben von Rumgucker
Erstmal wäre es nett, wenn Du etwas weniger schreiben würdest. Ich stoppe das lesen meist, sobald mir ein Fehler auffällt. So auch hier:
Zitat:Original geschrieben von Alex KiticEin heißer Glühfaden ist in reiner Wirkwiderstand und keine Stromsenke
Of course, set a fixed current sink, not a resistor which will change the current in the circuit changing the resulting ripple.
;deal2
How might I explain this to you in just a few words?
Imagine you need 10V 5A: does this mean 2 ohms?
Yes it does... but now imagine that 2 ohms are getting 11V instead: is it still 5A? No, it is not.
Most tube filaments are meant to be "defined" by the voltage across them (in this case, 10V) while the current across the filament may vary (as you can find out in datasheets). Thus although a filament is a resistive load, this has nothing really to do with the ripple we are discussing.
You need to put a constant current sink instead of the resistor because what you want to do is know what is the ripple for a given CURRENT because the current is what matters in the electronic transformer circuitry: you will be able to adjust the voltage later, but you need to know the current you are setting it for (for instance, 100mA). Knowing the load you want to power will relatively easily translate into current on the initial part of the half-wave circuit...
Hopeless, really.