Test and measurement

SchedaWith more complex electronic devices and system the tendency towards lower signal levels, particulary those involving microprocessors, has increased their susceptibility to interference, as the radio between wanted and unwanted signals becomes increasingly unfavourable. When electronic circuits are subjected to interference, their performance may be degraded causing malfunction or even catastrophic failure. The most common factors influencing electronic devices may be described as follows:

  • Compared with tube-equipped instruments having machanical switches, modern measuring and control technology incorporating microprocessors have had their signal and measuring levels decreased by one order of magnitude, while frequencies increased by a factor of 10. In addition, present process automation requirements dictate the use of commercially available microprocessor, which have to work impeccably often on-line under these hostile environmental conditions. The end is not yet in sight: newer devices will soon be appearing with still shrinking geometry and escalating sensitivity.
  • Levels of interference are growing due to new technological dvelopments.
  • More and more plastic material is being used for case designs, increasing the tendency to expose vulnerable electronics to interference rich environments.

Further developments in microelectronics circuits will bring about a marked reduction in tha interference thresholds. That is the reason why greater attention must be drawn towards the EMC behaviour of individual components and electronic systems.

IEC 61000-4-2


IEC 61000-4-4


IEC 61000-4-5


IEC 61000-4-8

50/60Hz Magnetic Fields

IEC 61000-4-9

Pulsed Magnetic Fields

IEC 61000-4-11

Voltage dips
Voltage interruptions
Voltage variations
in AC-power supply mains

IEC 1000-3-2

Harmonic current emission

IEC 61000-3-3

Low frequency supply voltage fluctuation

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Last Update
:12 Apr, 2008

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