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HOME : TECHNOLOGY CENTER : REFERENCE MATERIALS : GLOSSARIES : H Select a letter: A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z H H - Magnetic Field Strength (magnetizing or demagnetizing force) The measure of the vector magnetic quantity that determines the ability of an electric current, or a magnetic body, to induce a magnetic field at a given point; measured in oersteds (or kA/m). Hc - Coercive Force Equal to the demagnetizing force required to reduce residual induction, Br, to zero; measured in oersteds (or kA/m). The material characteristic of coercivity is taken as the maximum coercivity -- that value of H required to reduce the residual induction to zero after the material has been saturated (fully magnetized). Hci - Intrinsic Coercive Force Indicates a material's resistance to demagnetization. It is equal to the demagnetizing force which reduces the intrinsic induction, Bi, in the material to zero; measured in oersteds (or kA/m). As for coercivity, the maximum value of intrinsic coercivity is obtained after the material has been saturated (fully magnetized). Hard 1/4 HARD - A specific mechanical strength requirement; tensile strength is approximately 1/4*(tFH - tA), where tFH=tensile strength of full hard condition, and tA=tensile strength of annealed condition. 1/2 HARD - A specific mechanical strength requirement; tensile strength is approximately 1/2*(tFH - tA), where tFH=tensile strength of full hard condition, and tA=tensile strength of annealed condition. 3/4 HARD - A specific mechanical strength requirement; tensile strength is approximately 3/4*(tFH - tA), where tFH=tensile strength of full hard condition, and tA=tensile strength of annealed condition. FULL HARD - A specific mechanical strength requirement; tensile strength is approaching the maximum for most applications. Little ductility is left within the material. The material is usually cold worked 40 to 50%. Hardness A measure of the resistance of a material to surface indentation or abrasion. Hd The value of H corresponding to the remanent induction, Bd; measured in oersteds (or kA/m). See also BdHd. Hs - Net Effective Magnetizing Force The magnetizing force required in the material, to magnetize to saturation; measured in oersteds (or kA/m). Hall Effect Transducer A device which produces a voltage output dependent upon an applied DC voltage and an incident magnetic field. The magnitude of the output is a function of the field strength and the angle of incidence with the Hall device. Hard Magnetic Material A "permanent" magnet material that has an intrinsic coercivity greater than or equal to about 300 oersteds (24 kA/m). Henry The inductance of a circuit in which an emf on one volt is produced when the current in the circuit changes uniformly at the rate of one ampere per second. High Q Filters A unit of inductance. Hm Common symbol for maximum applied magnetizing force. Hysteresis and Hysteresis Loss Hysteresis is the tendency of a magnetic material to retain its magnetization. Hysteresis causes the graph of magnetic flux density versus magnetizing force to form a loop rather than a line. The area of the loop represents the difference between energy stored and energy released per unit volume of material per cycle. This difference is called hysteresis loss. It is one of two major loss mechanisms in inductor cores; the other is eddy current loss. Hysteresis loss is measured at low frequency to distinguish it from eddy current loss. Hysteresis Loop A closed curve obtained for a material by plotting (usually to rectangular coordinates) corresponding values of magnetic induction, B, for ordinate and magnetizing force, H, for abscissa when the material is passing through a complete cycle between definite limits of either magnetizing force, H or magnetic induction, B. If the material is not "driven" to saturation, it is said to be on a minor loop. Hysteresis, Magnetic The property of a magnetic material by virtue of which the magnetic induction for a given magnetizing force depends upon the previous conditions of magnetization. Hysteresisgraph An instrument that draws hysteresis loops. Also called permeameter. Copyright © Arnold Magnetic Technologies Corporation. All Rights Reserved. Please send all web related questions/comments to the Webmaster. TOP | BACK | HOME | HELP | MAP | CONTACT