Trilogy of Magnetics by Wurth Elektronik EMC / EMI Proactive Engineering


Understanding the subtleties involved with proper EMI / EMC design can be challenging. It involves competent knowledge of all the Design Disciplines; Digital Design, Board Layout, Signal Integrity, System Architecture, Power, and Mechanical. The parasitic circuits that are unintentionally created via RF signal coupling and induction are unseen and can be very confusing to the inexperienced engineer. Proper resources on hand can make the difference between success and product release failure.

One of the differences between HCT America and other test laboratories is our extensive experience in the area of Compliance Design, Proactive Engineering, and EMI / EMC Debug. Our staff has a history of expedited debugging for some of the most complex compliance issues in the industry. Solving problems that have taken whole design teams 4 to 6 months before realizing the problem was beyond their capability have been resolved using manufacture friendly solutions within three weeks to 3 days.

A design resource we use is a book distributed and published by Wurth Elektronik. Trilogy of Magnetics has been authored by Bernhard Rall, Heinz Zenkner, Alexander Gerfer, and Dr. Thomas Brander. The book highlights EMI / EMC design beginning with the basic principles of Inductive Components, RF Currents, and Magnetics, to real-world Applications, Circuit Design, and Component options for EMI design. HCT America maintains a direct affiliation with Wurth Elektronik via Joe Aguilera (area sales manager for the Western US region). He can be contacted at or 800-643-2661.


The Design Guide “Trilogy of Magnetics“ in its 4th edition The design guide for EMI Filter Design and SMPS & RF Design Circuit is completely revised, newly structured, and covers a multitude of new components and applications. The design guide is divided into the following chapters: Basic Principles, Components, and Applications. A keyword index, as well as a formulary, complete the book. The objective of the design guide, “Trilogy of Magnetics”, is to practically familiarize customers and users with the characteristics and applications of inductive components. The design guide was published 8 years ago for the first time and is now a standard work for lots of development departments and universities. Over 15,000 copies of the book have been sold in the last eight years. In the 4th edition, the explanation of old techniques and components has been set aside to have more room for new components and applications. Notably, a multitude of external authors from our customer base and our well-known manufacturers passed on their experiences and solutions in the Basic Principles and Applications section.

The following articles are exemplary highlights:

  • Calculation, dimensioning, and construction of customer-specific transformers (Do-it-yourself transformer design)
  • A transformer’s effect on return loss
  • Class-D amplifier
  • An introduction to frequency compensation
  • Basic principles of Ethernet & Power-over-Ethernet  Furthermore, the Trilogy includes over 200 practical examples of the following topics:
    • Filter circuits
    • Audio circuits
    • Video circuits
    • Interfaces
    • Motor control units
    • SMPS
    • Line filter
    • Power supply

Interested? Order the Trilogy for 49 €.

Chapter extracts

Article: WE / HCT USA
Editor: M. Danmole’
Image: HCT USA / WE