Those who have done the development work have such experience, test switch power supply or in the experiment heard similar products playing bad high voltage leakage sound or high voltage arc sound unasked: its sound or small, or sometimes no; Its rhythm may be deep or harsh or capricious

Audio noise generally refers to the audio signal produced by the switching power supply itself in the process of working, which can be heard by human ears with a frequency of 20-20khz. Electronic and magnetic oscillation frequency components within the scope of the human ear hearing, can hear the signal is produced. This phenomenon in power transformation has been known. At the beginning of the study with 50 and 60 hz often produce hate communication work power frequency transformer noise. If the load modulation with audio component, working at a constant ultrasonic frequency switch power converter also produces audio noise.

Low power electricity at ordinary times, audio signal usually has nothing to do with the converter. However, the designer may want to lower its acoustic emission circuit. Low power AC to DC converters, the 50 or 60 hz transformer core chips welded together, can make the level of noise to allow communication. High frequency switch converter ferrite transformers also USES a similar technology in the wood.

Advanced audio engineering equipment used to study the sound radiation of switch power supply. This device can be very accurately measuring absolute sound pressure level and sound spectrum, but the human sense of sound is very subjective. It's hard to say how much of a voice is heard, what is more difficult to determine how much in the specific application of voice is considered intolerable noise.

Acoustic radiation is similar to electromagnetic radiation, but there is no common baseline for measuring auditory tolerance. Therefore, designers can follow the following guidelines to deal with problems related to audio noise and reduce the sound radiation of products.