Your Humidifier's AC adapter contains a circuit that converts AC power to DC power or voltage. When this circuit works, it vibrates, causing the adapter to make a noise.
In normal use, this noise will not be noticed, but in quieter environments, such as late at night, it may be noticeable and unpleasant.
Please be assured that strict quality control has been carried out to ensure that this noise does not interfere with your use of the product.
We are currently working to improve the design and production of our AC adapters to reduce the noise.
We will do our best to provide you with better products and services in the future.
Thank you very much for your cooperation and understanding.