Würth Elektronik is launching the 4th edition of the "Trilogy of Inductive Components" application manual. The application manual for EMC filters, switched-mode power supplies and RF circuits has been completely revised, restructured and contains a large number of new components and applications. The technical book is divided into three main chapters: Fundamentals, Components and Applications. A technical and keyword dictionary as well as a collection of formulas round off the book. To bring inductive components closer to customers and users with their properties and applications in a practical way and without ballast - that is and remains the claim of the technical book "Trilogy of Inductive Components". The book, which was first published 8 years ago, has become a standard work in many development departments and universities and has been sold more than 15,000 times. In the new 4th edition, older techniques and components have deliberately not been explained in order to give more space to new components and applications. Remarkable is the large number of external authors from the customer base as well as from well-known manufacturers, whose experiences and solutions in basic principles and circuit technology can be found in this book. In the following, a number of new articles are mentioned, which are exemplary for many other innovations: - Calculation, dimensioning and construction of customised transformers (do-it-yourself transformer design) - Effects of the characteristics of a transformer on the reflection attenuation - Class-D audio amplifiers - Principles of frequency response correction for switching regulators - Basics of Ethernet & Power-over-Ethernet - In addition, over 200 practical examples on the following applications: o Filter circuits o Audio circuits o Video circuits o Interfaces o RF circuits o Motor control o Switching regulators o Mains filters o Power supplies.