Core-to-Core Noise Consistency of Ungapped Ferrite Cores in Resonant Capacitance Bridges
An empirical characterization of how interchangeable ungapped MnZn ferrite cores (SIFERRIT N41) are in low-noise AC resonant capacitance bridges. Each bridge's noise minimum is found by parabolic fitting of its resonance and summarized by a weighted mean and variance at 293 K and 140 K. Same-batch cores scaled to a common frequency agree to under 0.3% (293 K) and 0.6% (140 K), with sub-attofarad-per-root-hertz noise floors, establishing that cores can be swapped across an ensemble of precision bridges without degrading performance.
Performance Variance of Low Noise Resonant Capacitance Bridges While Replacing their Ungapped MnZn
Precision AC resonant capacitance bridges, built around a planar printed-circuit-board transformer wound on an ungapped MnZn ferrite core, achieve extremely low noise (sub-attofarad per root-hertz). …