Ken said:
Thanks for your answer. can you confirm the following then?
I always thought a b-field was magnetism and an a-field was the
electro-field which traveled with the b-field (when applicable) but at
right angles to it.
There is no field I've seen commonly referred to as the "a" field. The
"magnetic" fields are commonly referred to as the "B" and "H"
fields (again, related by the permeability of the material in which
the fields are established), while the "electric" fields are the "E"
and "D" (which are similarly related by the permittivity of the
material). The classic "electric" and "magnetic" fields are the
E and B, respectively, while the D and H are related to these
but you don't really need to worry about them right now. If
you get into a course on electromagnetic waves, etc., then you're
going to get into the differences, but not until then.
so then inductance is the storage of a b-field (magnetic "work") only,
where capacitance is the storage of an a-field (electrical "work")
only, correct?
More correctly, "inductance" is that property of a component
or conductor whereby *energy* is stored in the form of a magnetic
field, and "capacitance" is that property whereby energy is stored
in an electric field.
and so a coil when charged/induced at its max is only storing a
"magnetic potential", no electrical potential will exist at this time.
when the magnetic field collapses back through the coil then a larger
a-field will then be realized. right?
I'm not sure what you're trying to say here, exactly, but let me
take a whack at what I THINK it might be.
If you're running a direct current through an ideal coil (no
resistance), then a magnetic field is created by the coil and
there is a certain amount of energy in that field. There is no
voltage drop ("electric potential") across the coil in this case,
just a current through it. If, however, you attempt to change
the current (including trying to shut it off), then energy comes
back out of the field and creates a potential (voltage) across
the coil in such a way as to oppose the change. (If, for instance,
you try to open a switch which is carrying a sizable current through
a large inductor, you can get a HUGE voltage and the switch
will "arc over" as the inductor "tries" to maintain the current
through it.)
also, what is an h-field in common sense terms?
This is where things get a bit complex. To a physicist, the
B-field is the "magnetic field," while the H-field is the
*magnetizing* field; from an engineer, you'd commonly
hear these called the "magnetic flux density" and the
"magnetic field strength," respectively. About the best way
I can show a "common sense" difference is to go back to
an example I used in the last post - if you have an air-core
coil you're trying to use as an electromagnet, you will find that
that putting an iron core in increases the magnetic strength
significantly. The B-field is the same in both cases, but the H-field
has gone up with the iron core (due to the increased permeability).
Bob M.