Why is there a current noise when the Mijia Smart Air Purifier 6 is powered off?

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div:last-child { margin-right: 0 }If there is a current noise when the Mijia Smart Air Purifier 6 is powered off, please refer to the following information:
This noise is caused by the inductors in the DC-DC circuit of the air purifier. Since the circuit board and various functional modules require different working voltages, the circuit converts a constant voltage into different voltage levels to supply the load circuits;During this voltage conversion, the inductors switch at high frequency, continuously converting electrical energy into magnetic energy and back. This energy conversion causes a slight current noise from the inductors, which is a normal phenomenon;If you notice unusually loud or irregular noises, check that the device is placed on a flat, stable surface and contact after-sales service if necessary.