Abstract :
I am sure quite a few of us remember the first time we clamped an old speaker in a vise and tore out the magnet; in days past it probably involved a large hammer, vise grips and a lot of sweat, but eventually it gave in and freed itself, although I was never quite successful in freeing it from the surrounding flux concentrators as hard as I tried, this was always a frustrating setback. As a child you probably didn´t realize it, but you were actually disassembling a linear motor; I sure didn´t. Magnets seemed sort of magical at that age, and besides providing more than one pinched finger, they were treasured toys until they ended up stuck to the refrigerator door, and your mom got mad when she discovered that they were scratching the paint of her prized appliance; they seemed to magically disappear after that.
