In-circuit measurement of saturation flux density Bsat, coercivity Hc, and permiability of magnetic components using a digital storage oscilloscope

摘要

An oscilloscope performs an in-circuit measurement of voltage across, and current through, a core winding of an inductor, and derives the actual B and H values with n number of turns, receives data indicative of the magnetic length of the circuit, and plots the B_H curve. The oscilloscope then derives the value of Saturation flux density (Bsat), Remnant flux density (Br), Permeability (μ), and Coercivity (Hc) from this B-H plot. Characterizing the operating region of the magnetic component while it operates in a Switch Mode Power Supply (SMPS) under test, provides information concerning the stability of the power supply that was heretofore unavailable.