wrote:
On Jan 31, 6:53 pm, john smith wrote:

In article .com,

wrote:

Coils (inductors) are current storage devices.
Capacitors are voltage storage devices.


As if current and voltage were independent of each other?
The coil will produce a surge of current, which has a specific
pressure that we call voltage. You can't have current flow without
voltage; any flow (amperage) requires pressure (voltage) to drive it.
Just like water in a hose.

It seems that you need some basic physics repeat training.

The quote above about storage is correct for capacitances
and inductances.

An inductance converts current changes into voltage changes
in such a way that it opposes the original current changes,
that is, an inductance smoothes current flow at the expense
of voltage changes.

A capacitance converts voltage changes into current changes
in such a way that it opposes the original voltage change,
that is, a capacitance smoothes a voltage at the expense
of current changes.

The magneto produces a pressure upward of 20,000 volts. It
does this using a pair of coils and a switch (points). Your
automobile's ignition system probably produces 40,000 volts, again
using paired coils. Both of those systems have a primary coil that
produces the current surge (which has a voltage spike) when its
current flow is interrupted, and the collapsing magnetic field
produces the huge spike in the secondary coil for use at the spark
plug.

The voltage from a magneto (or a simple spark coil) comes from
two sources:

- the abrupt break of the current in the primary winding of
the coil. It creates a voltage spike to (in vain) keep the
current smooth.

- the transformation ratio of the primary to the secondary
winding in the coil.

A magneto works in the same way as a spark coil, but the initial
current is created by a generator action of the moving magnet.


The argument re current vs. voltage is a little like
Bernoulli's vs. Newton's theories of lift. They're both right, but
they address different aspects of the phenomenon.

Right, but they are independent as long as the circuit
impedance is not specified. It is the thing that ties
current and voltage together.

--

Tauno Voipio (MSEE, avionics engineer)
tauno voipio (at) iki fi
'