On Jan 29, 2007, at 7:28 AM, Lindy Mayfield wrote:

> L1, the choke or coil, will smooth out DC current.

Huh.  That *IS* a traditional way of thinking about an inductor.
But it's become a bit dated.  In this case, the inductor is an
energy storage element, and the combination of Q3, D1, and L1 is
one of those "standard subroutines"; in this case a boost-mode
voltage regulator.  In a modern circuit, an inductor is probably
more likely to be used in a switching regulator than in a filter.

I suppose the for L and C, you have to consider whether the part
is in a spot where it "sees" mostly DC, mostly AC, or mostly STEPs.
The physics is all the same, but the simplifications that lead you
easily to an understanding of the circuit are quite different.

BillW
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