Working point, Load Line or Operating line: when the magnet is working under open circuit condition, since the effect of demagnetization field, the induction strength of the magnet in working condition is not the Br under closed circuit condition, actually, it’s some point in
the B-H curve which is lower than Br. This point is defined as working point, D, as shown in the following picture. The straight line drawn
between the working point and the origin is called Load line, which is also known as operating line.
The slope of this line is defined as Pc, Pc=Bd/Hd=*(1-1/N). N is called the average demagnetization factor.
