6 Replies Latest reply on Dec 25, 2019 10:27 PM by colporteur

    what causes coil whine in inductors

    max2198

      on my desktop computer when i play demanding games i get whining from the inductors that are on the motherboard and graphics card. and it can get quite loud some times

      what causes the inductors to whine?

        • Re: what causes coil whine in inductors
          shabaz

          Hi Harry,

           

          The circuit is being used towards its upper limits, and enough energy is being dissipated that anything that can vibrate, is vibrating to the point that it can be heard (it can occur when there is some resonance to increase the amplitude of the audible vibrations).

          There's nothing much that can be done about it, short of trying different boards with different inductors and different designs. It's usually normal unfortunately. My PC does it too at certain loads. The manufacturer says it is normal.

          2 of 2 people found this helpful
            • Re: what causes coil whine in inductors
              colporteur

              I have a method that has proven successful in the past for high voltage transformers used in televisions with pictures tubes. The plates that make up the core of the fly-back transformers would oscillate. The plates were laminated in manufacturing to prevent this from happening but as the television aged things happen. The fix, use a hot glue gun to paste the core.

               

              This is solution is less than ideal but it did eliminate the sounds from the oscillations.

               

              Another paste is varnish but that can get nasty if the components get warm.

              • Re: what causes coil whine in inductors
                dougw

                The sound is probably due to magnetostriction. Magnetic fields in coils and transformers apply force to ferro magnetic materials and conductors (due to eddy-current magnetic fields). These forces cause metals to move or change shape slightly - which will move air which ends up as sound.

                The solutions are:

                • to immobilize the materials so they cannot move as much
                • add mass so the vibrations are reduced (and especially not resonant) at the frequency of oscillation
                • to absorb the air fluctuations (acoustic damping)
                • create a vacuum so there is little air to couple to
                • during design the frequencies can sometimes be designed to be at inaudible frequencies
                2 of 2 people found this helpful