Electromagnetic Interference (EMI)

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Electromagnetic Interference (EMI)
Electromagnetic Compatibility (EMC)
Presented by Devraj Sabat EC200117322
Under the Guidance of Mr. N. Srinivasu
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AGENDA

• EMI
• SOURCES OF EMI
• REDUCING EMI
• EMC
• EMC DESIGN CONSIDERATIONS
• EMC EMI TESTING

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INTRODUCTION

• EMI-
• It consists of any
  unwanted conducted or radiated signals of
  electric origin that can cause degradation in
  system or equipment performance.
• EMC-
• It is the ability of the system to
  function as designed without any degradation in
  performance due to EMI with in the operational
  environment

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Classification of EMI

• INTRASYSTEM EMI-
• EMI problems with in the system one is
  dealing with.
• INTERSYSTEM EMI-
• EMI problems, that occur between two
  or more systems.

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EMI arises due to three basic factors

• Sources
• Transmission Path
• Response

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Sources of EMI

• Natural EMI sources
• Man made EMI sources
• Broadband EMI sources
• Narrowband EMI sources
• Conducted EMI sources
• Radiated EMI sources

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Reduction of EMI

• Both Filtering Shielding techniques are
  used to reduce electromagnetic disturbances.
• To reduce noise due to EMI at sources by
  EMC oscillators.

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Electromagnetic compatibility (EMC)

• First, EMC implies that the equipment will not
  generate unacceptable interference emission
  levels which could cause interference .
• Second, EMC implies that the equipment can
  tolerate ambient levels of interference
• without degradation of performance

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EMC Design considerations

• Connectors
• Grounding
• Shielding
• Components
• Electrostatic discharge

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Testing

• Low level testing-
• Component, Equipment, Subsystem testing
• Intermediate level testing-
• System testing
• High level testing-
• Electromagnetic environment with the test
  
• item

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Testing

• Compliance tests-
• Performed at the end of design.
• Engineering tests-
• Deals with potential problems in the
• designing process .
• Audit tests-
• It is associated with manufacturing
  quality

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Conclusion

• EMI is a major problem in the development of
  systems.
• EMC must be taken in to consideration during the
  design stage.
• Environmental reliability testing is used to
  eliminate potential problems
• There are many EMC standards used in the
  regulation of products that may cause EMI.

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References

• Electromagnetic Compatibility Design Guide for
  Avoinics and Related Ground Support Equipment by
  AD NAVAIR.
• Electromagnetic Compatibility, design handbook
  series 1.0.
• A.A. Smith Jr., Coupling of External
  electromagnetic fields to Transmission lines,
  John Willey Sons.
• www.google. Com
• Military specification, Electric Cable, Aerospace
  vehicle, General specification for, MIL-C-7078,
  August 9, 1971.

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Thank you
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