Hello all, as time goes by I find myself doing more and more dc/dc work, 
including things like switcher battery chargers and high power LED 
drivers, mostly successfully but sometimes not.

In doing the design of such things, the inductor is often the biggest 
question.  Datasheets for whatever IC is running the show of course give 
guidance, but sometimes this is less than complete, and sometimes 
they'll give typical but not corner-case information, and sometimes 
they'll give info needed to run whatever it is at max power, and I'm 
designing for 1/5 of that, and don't want to use a way overkill inductor.

Ok, all this leads up to the question: how do I measure current through 
an inductor as it is operating under normal loads in such designs?  If I 
put a 0.1R resistor in series, I can get some kind of measurement (with 
a scope, 2 channel, in difference mode), but for some inductors adding 
0.1R to its resistance changes the overall operation considerably.

The goal of all this is twofold - firstly to check that the inductor 
isn't saturating at corner cases, and secondly to see how predicted 
operation compares with actual and maybe optimize the design to use 
smaller/cheaper inductors.

Suggestions?

Thanks everyone!
J
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