Digital Measurement of Ferrite Hysteresis Loops

The input data needed for engineering computations on ferrite for cavity tuning prove to be almost nonexistent in industry or private research. It would appear that the accelerator designer´s choice is either a) accept crude input data and play safe by overdesign, or b) take time out to assemble a measuring system to permit a close design. We chose the latter alternative; this paper describes our digital measuring set for major and minor hysteresis loops in ferrite. The B integrator operates under a hardwire program with digital drift and zero correction. A small control computer formats the output data for typewriter, cards, paper tape, or magnetic tape. A code run on a separate computer fits the measured data points to any one of several compact series expressions for the B-H loop, presents analogue plots and derives numbers for permeability, stored energy and Q.