>From =3D=3D> http://en.wikipedia.org/wiki/Electrical_impedance Electrical impedance is the measure of the opposition that a circuit presen= ts to the passage of a current when a voltage is applied. In quantitative t= erms, it is the complex ratio of the voltage to the current in an alternati= ng current (AC) circuit. Impedance extends the concept of resistance to AC = circuits, and possesses both magnitude and phase, unlike resistance, which = has only magnitude. When a circuit is driven with direct current (DC), ther= e is no distinction between impedance and resistance; the latter can be tho= ught of as impedance with zero phase angle. Gus > On Mar 22, 2013, at 10:42 PM, Sean Breheny wrote: >=20 > OK, as far as I know, it is just copper coil resistance. If you wanted > DC resistance, you really shouldn't use the term impedance, then, > because impedance really means the AC phasor quantity whose real part > is the AC resistance at the frequency of interest and whose imaginary > part is the reactance at the same frequency. >=20 > Sean >=20 >=20 > On Fri, Mar 22, 2013 at 7:46 PM, YES NOPE9 wrote: >> How is headphone impedance ( DC ) created ? That is... is it due to the= copper coil resistance or is additional resistance added via more resistiv= e materials or discrete resistors ? I am not asking about AC impedance. >> Gus >=20 --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .