SilverStone SX500-G PSU Review

EMC Pre-Compliance Testing

EMC, EMI & EMS Acronyms

Electromagnetic Compatibility (EMC): The ability of a device to operate properly in its environment without disrupting the operation of other close-by devices.

Electromagnetic Interference (EMI): This represents the electromagnetic energy a device emits, which can cause problems in other close-by devices if it is too high.

Electromagnetic Immunity (EMS): Tolerance to electromagnetic emissions.

Equipment & Standards

To properly measure the EMI that a device emits, you need special equipment defined by the CISPR 16-1-1 specification. To learn more about our EMI testing equipment, please check out How We Test Power Supply Units.

In order to minimize EMI noise, some standards have been established. The corresponding standards for Information Technology products are CISPR 22 and its derivative EN 55022. In the EU, every product featuring the "CE" marking has to comply with EN 55022. Both CISPR 22 and EN 55022 divide devices into two classes, A and B. B-class equipment is for domestic environments, so its allowed EMI emissions are significantly lower than for A-class devices.

CISPR / EN55022 Limits
CISRP 22/ EN 55022 Class A Conducted EMI Limit
Frequency of Emission (MHz)Conducted Limit (dBuV)
Quasi-peak

Average

0.15 - 0.5079

66

0.50 - 30.073

60

CISPR 22/ EN 55022 Class B Conducted EMI Limit
Frequency of Emission (MHz)Conducted Limit (dBuV)
Quasi-peak

Average

0.15 - 0.5066 - 56

56 - 46

0.50 - 5.0056

46

5.00 - 30.0060

50

Conducted EMI Results

We measure two major EMI spikes at <1 MHz frequencies. Usually, the region up to 2 MHz is where most of the noise spurs occur.

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3 comments
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  • love4earthwk
    I'm afraid I can't find ETA-B and LAMBDA B- ratings in cybenetics sites.

    https://www.cybenetics.com/index.php
  • Aris_Mp
    there has been a change/refresh on the ratings. There is no more B, C, D ratings in the new ratings. The thresholds/ranges are exactly the same, just the naming scheme has been changed in some of the ratings. If you go to the ETA and LAMBDA pages you will find the new ratings.
  • Lutfij
    Good write up Aris! Should I revive my SFF system build, I'll know what to shoot for amongst a plethora of STX PUS's.