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
BFL13 wrote:
I am wondering if it was operator error in starting/ stopping sequence that did for both thermistors.
From time to time I mention in posts that I'm much amused (And occasionally scared) by some of the advice given in these forums.
YES, the thermistor is designed to pass different amounts of current depending on how long it's been doing it (It heats up when current flows and since it is a Negative Coefficient device the resistance thus goes down.) If you "Hot switch" (turn off and quickly back on) too much current can flow, this can both cause the thermistor to overheat (it never gets to zero) and damage down-line stuff as well.
The 3 minute rule (used for air conditioners) is a good one here too, though it may be a bit longer than needed.
As I stated in another thread.. I have designed and built power supplies (These are basically what we call single stage converters) for use with some of my radio gear in the past. So I've done the hot switch thing, Though since I over build all it cost me was a fuse or two.
