Converter In-Rush Thermistors etc, UPDATE -4
UPDATE on 17 Nov, Update 2 on 22 Nov, Update 3 on 16 Jan 14, Update 4 on 19 Oct 14. --------------- In a recent thread there was mention of how you can wreck your gizmo (in my case a converter) ...
Forum Discussion
Salvo wrote:
Size doesn't matter that much. The 2 ohm device can take almost twice as much energy (to destruction) as the 5 ohm device. Go for the 2 ohm. It's a slam dunk.
Sal
Hardly a slam dunk. First the two ohm device also has to absorb way more energy, and second allows way more inrush current across the power switch contacts.
It seems like folks are ignoring the effects on other parts of the circuit. Do NOT ignore the effects of high inrush current on the power switch. It occurs as the switch contacts are bouncing on contact and can result is premature failure of the power switch as well.
And then there is diode current etc.
The idea it to provide a safe controlled startup current not to slap in a thermistor and think it is doing what is expected when it may not be.
BTW just prior to Ken Whites post on energy absorption, (see previous page) I did an analysis and my caculations resulted in essentially the same conclusion.
But Ken did a much better job of explaining than I would have, so there was nothing I could add to the concise explaination and result summary.
