RF Inductors & Magnetics

Training Center Classroom

Welcome to this installment of EE Classroom on RF inductors and Magnetics

Even the most sophisticated electronics designs for communications, automotive, industrial, space, military and space environments incorporate the simple inductor. Selecting an inductor for a given circuit in your specific application still involves some research and basic understanding of the types of inductors available and their unique properties.

In this classroom, we’ll cover the basics of inductor properties, magnetism, EMI, and inductance, and the design of analog active filters. You’ll learn about measuring inductance, how to avoid EMI, and the distinctions between active and passive filters and their key parameters. For an RF and microwave refresher, check out the answers to the frequently asked questions around noise figures and the various bandpass filter implementations. Finally, four application notes take you through basics of inductors, conical inductors, LC filters, and ferrite beads.

And, remember, it’s a classroom – so keep the “noise” down…

Aimee Kalnoskas

Senior Editor, EE World Online

RF Inductors & Magnetics Classroom Sponsored by

Magnetics  •. Test & Measurement 

Power supply designers take a hard look at soft magnetics

Measuring inductance

Any conductive body has a certain finite inductance. This inductance is an intrinsic property of a conductive body and it is always the same.

Measuring active and passive filters

Mutual inductance & transformers: when EMF becomes EMI

The promise of high efficiency and small size brought by super-fast switching power supplies could be delayed by a lack of magnetic materials that are up to the task.

In regard to their intended purpose, electronic filters are classified according to the specific part(s) of the spectrum that they pass or reject.

There’s a lot of formulas involving integrals, derivatives, differential equations, and more that explain the precise relationships between electricity and magnetism.

Related Resources

What is an Inductor?

What is a Conical Inductor?

What is an LC Filter?

Wirewound Ferrite Beads: Outperforming Traditional Chip Ferrite Beads

RF  •  Microwave  •  Filters

RF/microwave noise, Part 1: Noise figure basics

RF/Microwave noise, Part 2: Noise temperature and applications

RF/Microwave bandpass filter implementations: Cavity and comb filters

RF/Microwave bandpass filter implementations: Distributed filters

An overview of power, impedance and matching, and two noise-related parameters: noise factor (and figure) and noise temperature.

Looks at the additional parameter of noise temperature, as well as the impact this parameter has on system performance.

Some of the specific technologies and approaches used for these filters, and their relative attributes.

Just say the word “filters,” and for many engineers, the mention of this topic stirs a mix of feelings ranging from fear to relief.

The Basics

 Properties of inductors

Designing of Analog Active Filters

 Magnetism, Electromagnetism and Inductance

When select selecting an inductor for a given circuit, it is important to understand their various specifications and non-ideal characteristics.

A look at the different types of analog filters first and examples of such types of filters.

To understand inductance, it is important first to understand magnetism and electromagnetism.

Coilcraft produces inductors for a long list of customers in telecommunications, computers, instrumentation and consumer electronics. Most are standard, off-the-shelf products, but many are still custom designed to meet customers' specific requirements. 

Coilcraft's worldwide headquarters are in Cary, Illinois, 30 miles northwest of Chicago's O'Hare Airport. In addition to corporate offices, this facility houses our engineering department plus manufacturing. European headquarters are located in Cumbernauld, Scotland, near Glasgow. There are another nine plants in the U.S. and Mexico as well as production centers in Scotland, Taiwan, Singapore, China and Malaysia. This diversity of locations offers several advantages to our customers.