[AMRadio] Extra Class isn't dumbed down? (was Viking 1)


Jim Liles hallicrafterssr2000 at k9axn.com
Tue Dec 22 21:50:21 EST 2015


Hi Rob,

I wasn't suggesting memorizing everything.  I suggested that we all memorize
formulas and concepts not just newbies.  Now, because they may memorize more
than others doesn't qualify them for target practice.

Rob, your comment "Current lags in an inductor because the field is induced
first but the bulk of the current doesn't flow until the field collapses" is
not what I was looking for.

The question that I ask is "How does the current get to the point that it
lags the voltage by 90 degrees in an inductor?".

That's a universally asked question by new comers to the hobby including
myself 62 years ago as a Novice.

Explain it using a single sine wave applied to an inductor; don't cloud the
explanation with resistance, just inductance.  Don't worry about the values,
explain how and at what time during that first cycle there is a 90 degree
relationship: or any cycle after the first.

Articulate the phase relationship at the end of each 1/4 cycle.

I asked this because rote learned concepts do not necessarily mean there is
understanding; but they are a good starting point.

If this is of no interest to anyone simply erase it and I will simply
evaporate.  Some may find it interesting.

Kindest regards Jim K9AXN






-----Original Message----- 
From: Rob Atkinson
Sent: Tuesday, December 22, 2015 5:22 AM
To: Jim Liles
Cc: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Extra Class isn't dumbed down? (was Viking 1)

Current lags in an inductor because the field is induced first but the
bulk of the current doesn't flow until the field collapses.

you can't justify memorizing _everything_ because many have memorized
math formulas.  Sorry, but that's a false analogy.  Try something
else; good luck.

73 Merry Christmas

Rob
K5UJ 



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