Introduction to Interference Suppression.
Written by Almag., based on a paper originally presented at an IEE colloquium, this article explains the difference between common-mode and series-mode interference, and gives examples of the two very different types of circuit required for suppression.
As both types of interference are present in many types of equipment, combined suppression circuits are shown, including a cost-effective way of using common-mode choke leakage inductance to provide a measure of series-mode suppression simply by adding two capacitors.
Included is an explanation of the differences between common-mode and series-mode choke construction, with a review of the constraints on the types of magnetic core that can be used.

Introduction to Powder Cores for Power Chokes.
Written by Almag. The background to ferromagnetic and ferrimagnetic cores are described from first magnetic principles, leading on to the properties and advantages of the various families of iron powder cores and nickel-iron powder cores.
Comparisons of core losses, ripple frequency range and the inductance characteristics of the various types of core for dc power choke applications are given, with a summary of relative costs for the wound chokes.

Power Conversion Choke Standard Ranges.
Written by Almag. A summary of typical frequency ranges, relative inductance values, inductance swing under load and cost comparisons for Almag’s five distinct standard ranges of power conversion chokes with over a thousand chokes rated from 0.3A to 95A.