At 02:03 PM 8/18/98 -0700, Simon Matthews wrote:
>I believe that I have the definitive analysis of why the current through
the spark plugs is NOT supplied by the capacitor.
>
>I humbly believe that Barney has made another mistake in his anaylsis: he
refers to a 'wad' of electrons being built up on the capacitor when the
points open, but in fact, it is the reverse, the plate (terminal) of the
capacitor that is connected to the points is depleted of electrons -- as
the points open, the current flow is into the capacitor, but as we all
know, electrons are negatively charged, so for current to flow into the
capacitor, electrons must flow out of it.
>.... [snip] ....
I love the wording here, and I hope it was meant to be slightly humorous.
Yes, the electrons do flow in the opposite direction of our traditonal view
of current flow. I have been attempting to phrase the discussion in terms
of current whenever possible, because it's a bit more intuitive, and speak
of electrons only when it is significantly different than current. And I
try to keep wording "current neutral" (pardon the pun), so that the
polarity of the battery doesn't affect the discussion. I hope that's
making it through in the translation.
Further, the direction of the current flow and which side of the capacitor
is charging or discharging is dependent on battery polarity, for which our
beloved MGs may be wired either way (correctly or otherwise). I don't care
whether you think of the charge on the capacitor as electrons or as "holes"
(deficiency of electrons). The point was that there is a charge on the
capacitor that is passed through the secondary winding to (or from) the
spark plug to provide the spark at the plug.
And I'm still trying to find out where Dan thinks that secondary current is
coming from (or going to) if it's not from (or "through") the capacitor.
That's all. But when you try to simplify the answer, someone is bound to
jump in with a complicated explanation of why that simplification is
incorrect.
Barney Gaylord
1958 MGA with an attitude
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