When designing the safety of electronic product, the following principles should be taken into consideration to prevent such hazards from happening:

Electrical shock- the hazard coming from the shock of electrical equipment is a direct threat to the users, therefore being electrical shockproof has become the least requirements, as a result it is necessary for a electronic product to have sufficient measures for prevention of electric shock from happening.

Hazards of energy- the short circuit of the output terminal with high current or short circuit of terminal with high-capacity capacitor (e.g. high-capacity electrolysis capacitor) may give rise to high current, even spark, leakage of melted metals, even inflammation; nevertheless the hazards of low voltage can not be ignored; therefore the corresponding measures is necessary to be taken for the purpose of protection.

Hazard of inflammation-inflammation poses not only direct threats to the users’ personal safety, but also as a threat to surroundings, furthermore to more personal safety and public environment. The influences of secondary product in the process of inflammation, the influence of smog concentration on the survival of personnel on the inflammation site, the toxicity of secondary product threat the lives of on-site personnel; the corrosivity of secondary product threats the on-site personnel and equipment, therefore the inflammation has long been seen as the key item to be prevented in designing the electronic product.

Hazard of over-temperature-the over-temperature of external parts or materials may result in inflammation. In addition, scald is possible to be caused by the over-temperature of external parts, especially which of the external parts with excellent thermal conduction.

Hazard of mechanical hazards-inadvertent touch on moving parts may result in personal injury. For instance, a touch on a high power fan with vanes rigidity in exceedance of the specified values at high RPM may cause severe consequences. For static parts or the whole equipment, the corresponding measures for preventing mechanical and physical injury from happening can not be ignored as well. For example, a high center of gravity of the equipment may cause it turnover, which will result in personal injury, while poor design or machining may produce sharp edges or angles that are possible to injure the users; the accidental explosion of high vacuum element is likely to be risky to the personnel and so forth.

Hazard of radiation-the radiations that may cause personal injury include audio radiation, ray radiation (including infrared and ultraviolet ray), electrolytic radiation and so on. With the wide-spreading of electronic techniques, the electronic and electric products with the radiations above mentioned have entered each building and every family. The users of such products, especially the household women and children are not familiar with the radiations while having little awareness of self-protection, which should be the focus of designers’ attentions.

Chemical hazard-a touch on hazardous chemical liquid (e.g. acid, alkali, mercury) or their vapors, chemical gas or smog (e.g. hydrogen chloride gas, chlorine gas) may cause personal injury。When such substances are contained in product, it is necessary to take sufficient measures to prevent the people from touching them.