Sorry Charlie:
I've written all of this before and given the technical aspects elsewhere.
Suffice it to say that as the magnetic field inside the coil collapses the
magnetic lines of flux in the primary windings cut through the wires of the
secondary windings. This induces a current in the secondary windings. As this
current in the secondary windings increases in itensity, it also has associated
with it an increasing magnetic field. The magnetic lines of flux of this new
magnectic field creates a current in the primary windings opposite to that
created by the initial field: right hand rule. As a result this new emf has a
current which now flows in the opposite direction in the primary circuit. (This
same phenominum also occurs in the secondary windings.) Although this new
current, or emf, has been called a "back emf" or other layman's terms, it is a
misnomer simliar to having used Russia to designate the U.S.S.R.
However, you still have provided no information to disprove my statement "You
can open the points with a finger nail ... it won't "fry you." and "Did you
actually try it be (before) expounding?"
I bet you still haven't gone out to the MG taken off the distributor cap and
rotor, turned on the power, and opened the points with your finger to feel the
initial voltage, and the voltage created by that "back emf". Try it, I dare
you. If you feel anything, which you won't most of the time, you will find it no
worse than the licking test used to determine the condition of a 9 volt
transistor radio battery. I tripple dog dare you!
Blake
Degrees in math, physics, computer science, elementary education and a few other
areas.
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