"klem kedidelhopper"

This is a very well written article Phil however I have a question. In
"voice coil facts" you state:

"When a current is passed through a voice coil, heat is generated. The
amount of heat in watts is given by the very simple formula:

P = I² * R - where I is the RMS current and R is the actual
resistance of the wire, at any temperature"

Admittedly my AC theory is a bit rusty, as am I but since a voice coil
has an inductive component to it shouldn't the formula incorporate
the J factor, (R+JX)? Or is this just a theoretical example of perhaps
a DC current being passed through the voice coil? Lenny


** Sometimes the facts are SOOOO simple folk refuse to believe them.

In any complex, reactive circuit ONLY the resistive components dissipate
actual heat.

Inductive or capacitive components in series with resistive ones only act to
REDUCE the current flow.

So, with a speaker voice coil, one only has to know the RMS current flow and
the actual R value to calculate the HEAT in watts.

R varies with temp, so watch out.


.... Phil