April 2011 Archives - In Compliance Magazine

The Future of Battery Technologies

In order to ensure that a battery-driven product functions properly, there are different methods of testing and evaluating the battery’s functioning and safety. There are four different categories of tests that can be used in order to qualify a battery.

EMC Archaeology: Uncovering a Lost Audio Frequency Injection Technique

Injection of audio frequency ripple on equipment input power conductors has a long history, going back to 1953 (MIL‑I‑6181B) in the United States military, and at least as far back as 1961 in commercial aviation (RTCA/DO‑108). Audio frequency injection has been accomplished by inserting the secondary windings of a coupling (isolation) transformer in series with the power conductor to the test sample. While various transformers had been used prior to the 1960s, one has become standard since 1963. That Model is the Solar Electronics Model 6220, designed in 1962 and accepted by the United States Air Force in 1963 as being superior to previously used injection transformers. [1]

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.

No Sleeping in Seattle: A Recap of CISPR Projects from the 74th IEC General Meeting – Part 2

In this second installment of a two part article, we continue our review of the recent meeting of IEC-CISPR held in October 2010 in Seattle. In the first part of this article, we have described the current changes affecting the basic standard CISPR 16 and the activities of its experts within CISPR sub-committee (SC) A. We now take a look at the activities of the other CISPR sub-committees responsible for preparing the CISPR product standards. We also describe some of the projects shared by CISPR and IEC TC 77B (High Frequency Phenomena).