The Basic Principles of Shielding

1403 F4 coverToday’s electrical and electronic devices are subject to mandatory EMC requirements throughout the world. Many devices operate at high frequencies and are very small. They are placed in nonconductive plastic cases providing no shielding. Essentially, all these devices cannot meet these mandatory requirements or they may cause interference to other devices or receive interference causing susceptibility problems without a proper program of EMI control. This program consists of identifying the “suspect” components and circuits that may cause or be susceptible to EMI. This is completed early on in the program to allow for an efficient design in keeping the cost of dealing with EMI as low as possible. A complete EMC program consists of proper filtering, grounding and shielding. This article will discuss the latter, but the other factors cannot and will not be ignored or given insufficient priority.

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A 1kV Discharge Directly onto a Staple Leads to Increased Energy Penetration Inside Metallized Static Shielding Bags

1311 F2 coverEditor’s Note: Due to the overwhelming amount of positive feedback from the September 2013 issue of In Compliance (pp. 42-48), a follow-up article with additional lab testing by the author was necessary to respond to an aerospace prime.

Thank you for your informative article on “Pin Holes & Staples Lead to Diminished Performance in Metallized Static Shielding Bags.” Have you considered what happens if there is an ESD discharge to the staple in a bag?

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Pin Holes & Staples Lead to Diminished Performance in Metallized Static Shielding Bags

1309 F4 coverAs early as 1985, the author recalls re-occurring discussions of the effects of puncture holes from component leads and stapling of static shielding bags.

In July 2013, the ESD Experts page on LinkedIn® started a discussion by a USA computer manufacturing company that generated participation from end users, suppliers and consultants both here and abroad. In years past, some held opinions that pin holes do not greatly affect static shielding of metallized bags. There is, however, minimal published data to fall back upon regarding this subject matter.


New Test Methods to Determine the Shielding Effectiveness of Small Enclosures Defined in IEEE P299.1

Today’s end-use electronic equipment has a number of characteristics that require protection from the electromagnetic environment. These characteristics include the growing use of digital electronics (still with a layer of analog electronics); multiple inputs and outputs for power, data, controls and indicators; ventilation for air flow and thermal management; and small openings for accessories. Few pieces of equipment use only one microprocessor. Multiple digital packages (i.e., integrated circuits) are used for small and large amounts of memory, signal processing, and input/output control just to name a few. The days of having just one power cord and a few knobs for control have long since past.


Travels with Frosty: Days in Turkiye

Frosty and I went to Turkey to do a little shielding work. “Travels with Frosty,” coming at you. We rendez-vous’d at the United Counter, Frosty sporting his signature cowboy boots and white T-shirt, a ponyta... Read More...

Assessing the EMC Performance of PCB Shields by Electromagnetic Modeling

In the past EMC Engineers have relied on metallic enclosures to contain electromagnetic fields and meet radiated emissions limits in military and consumer products. Modern commercial electronics products typically use molded plastic enclosures since they are considered to be aesthetically more pleasing than a metal enclosure, but also to save weight and cost.