small valves

Tore> On Mon, 2005-04-25 at 13:39 -0400, Allison wrote: Tore> Are these cores suitable for use in making data memories? Tore> Ie. could one hypothetically make a core store today, using Tore> those cores? Has anyone done this? Do the current-day cores Tore> have better properties for use as memory than the ones used in Tore> past-day cores? Tore> Forgive me if this is a stupid question. Not a stupid question at all. No, those cores are not suitable for core memories. The issue is the "hysteresis curve" -- which shows the magnetization of the core as a function of the applied field, or something along those lines. Cores used for transformers have hysteresis curves that are very nearly a straight line. Cores for memory have a curve that looks more like a rectangle. The difference tells you whether the material remains magnetized after the applied field goes away. For transformers you want that NOT to be the case. For memory cores, you do. So the material is more like something you'd use to make permanent magnets. paul