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Switching power supply emission the electromagnetic waves

Discussion in 'Power Electronics' started by konkot, Jun 21, 2018.

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  1. konkot


    Jun 21, 2018
    Whenever i turn on my computer, the radio is being jammed
    i known the reason is the switching power supply inside the computer
    when it work, it emission the electromagnetic waves
    My question is:
    - What is the electronic component of the power supply make the emission
    - If i use a power supply with higher capacity, is the emission decreased?

    thanks a lot
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    Nov 17, 2011
    It is not a single component, it is the combination of the switching transistor, steep edges of the switched voltage and ringing effects of transformer and capacitors.
    It is hard and expensive to minimize the creation of the noise. What is done instead is reducing the effect (the actual emission of the noise) by filtering the inputs and outputs of the power supply. In your case these filters are obviously not well designed.

    Not necessarily. Noise emission is a quality issue, not a power issue. A badly designed low power supply may emit more noise than a well designed high power supply. Or vice versa.

    Before swapping the power supply you can try a power strip with integrated line filter to reduce emitted noise.
    A ferrite over the power cord next to the input to the PC may also help.

    Otherwise get a quality power supply which has good built-in noise suppression and is rated to match your PC's power ratings (add 20 % spare power to account for ageing of the power supply or rising power demand in case you add components to the PC).
    konkot likes this.
  3. kellys_eye


    Jun 25, 2010
    I find it easier to bluetooth the radio from a different location or receive it via internet anyway..... The cost/effort of trying to reduce the RFI from a PC simply isn't worth it.
  4. dave9


    Mar 5, 2017
    If it is not a known good quality PSU design then I would replace the PSU now, before it fails and takes other components with it.
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