Browse Prior Art Database

Insuring an EMI Depletion Path

IP.com Disclosure Number: IPCOM000035917D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Albrechta, J: AUTHOR [+4]

Abstract

Disclosed is a method of transferring collected electro-magnetic interface (EMI) emissions from covered printed circuit cards to the machine ground. This insures that printed circuit cards in an electronic package fall within certain specified emission levels. (Image Omitted)

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Insuring an EMI Depletion Path

Disclosed is a method of transferring collected electro-magnetic interface (EMI) emissions from covered printed circuit cards to the machine ground. This insures that printed circuit cards in an electronic package fall within certain specified emission levels.

(Image Omitted)

The printed circuit card is sandwiched between steel (1) and nickel-coated plastic (2) covers. Even though the covers touch each other, they act as individual parts. EMI charges build up on the plastic cover and need to be transferred to the metal cover, which provides the drain path to the machine ground.

The drainage path between the two covers is provided by an EMI spring (3). This spring clamps (4) over a support feature (5) in the steel cover. The spring arms (6), which are folded over to provide strength, apply a continuous pressure against the nickeled surface of the plastic card cover.

This low cost spring, which may be installed by hand, provides an EMI depletion path capability over the full range of system-operating temperatures and has a negligible airflow impact.

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