Static electricity on equipment or human body can reach tens of thousands or even hundreds of thousands of volts, and it often reaches hundreds to thousands of volts under normal working conditions. The human body can carry thousands of volts or even tens of thousands of volts of static electricity due to its own actions and contact-separation, friction or induction with other objects. Static electricity is the result of unbalanced positive and negative charges in a local range. It is a kind of electric energy, which remains in the performance of objects and has the characteristics of high potential, low power, low current and short action time.
The main measures of electrostatic control are: leakage and dissipation of electrostatic, electrostatic neutralization, electrostatic shielding and grounding, humidification and so on.
The breakdown damage of components caused by electrostatic discharge is the most common and serious electrostatic hazard in electronic industry, which can be divided into hard breakdown and soft breakdown. Hard breakdown is one-time dielectric breakdown, burning or permanent failure of components; Soft fault is the deterioration of device performance or the decline of parameters.
Electrostatic sensitive components and printed circuit boards must be transferred and stored between processes in the production process, and anti-static feed boxes, component boxes, turnover boxes, turnover trays, etc. Must use. So as to prevent the harm caused by electrostatic accumulation.
Electrostatic sensitive components and printed circuit boards must be packaged into finished products with antistatic shielding bags, packaging bags, packaging boxes, strips, baskets, etc. To avoid electrostatic damage during transportation.
In the production process of electronic products, components and assemblies of finished products often contact, separate and rub with equipment and tools, resulting in static electricity. Anti-static pads, turnover vehicles, maintenance kits, tools, working chairs (stools) and so on must be used, and static electricity can be quickly discharged through proper grounding.
Triboelectrification and human static electricity are two major hazards in electronics and microelectronics industries, but static electricity is not a hazard, and the hazard lies in static electricity accumulation and electrostatic discharge, which must be controlled.
When an electrostatic field is formed around an electrostatic object, it will produce mechanical effect, discharge effect and electrostatic induction effect.
Due to the mechanical action of static electricity, dust particles floating in the air will be adsorbed on electronic components such as silicon wafers, which will seriously affect the quality of electronic products. Therefore, anti-static measures must be taken to clean the work area.
The walls, ceiling and floor of the clean room should be made of antistatic and dust-free materials, and a series of electrostatic protection measures should be taken for operators, workpieces and appliances.
In order to understand the electrostatic electrification in the production process, judge the influence degree of static electricity in the production process and test the quality of anti-static products and equipment, it is necessary to measure static electricity and related parameters.
The measurement of static electricity is mainly the measurement of static voltage, material resistance, grounding resistance, static attenuation period, static amount, static elimination performance of static eliminator, charge distribution surface density and so on.
Electrostatic protection is a systematic project, and any omission or mistake in any link will lead to the failure of electrostatic protection, so we must always guard against it.
How to prevent static electricity in spring
In the dry spring, we often encounter various static phenomena in our daily life. Static electricity makes people uncomfortable, but also causes headaches, insomnia, irritability and other symptoms, and even leads to rash and arrhythmia, which is more harmful to neurasthenia and mental patients.
1. When the weather is dry, you can also not sprinkle some water at home, or put one or two pots of water in places where it is not convenient to wet the floor to increase the indoor air humidity.
2. Electrostatic particles will be generated around the TV screen, which will absorb a lot of floating dust in the air and have adverse effects on human body and skin. So, don't put the TV in the bedroom. People should open the window when watching TV, keep a distance of 2-3 meters from the TV, and wash their hands and faces after watching it.
3. For the elderly, children, electrostatic sensitive person, patients with unexplained heart disease, neurasthenia and mental patients, it is suggested to wear pure cotton underwear in winter to reduce the adverse effects of static electricity on human body.
4. Bathing and changing clothes frequently can effectively eliminate the static charge accumulated on the surface of human body.
5. Barefoot is good for releasing static electricity accumulated on the body surface. Don't miss the chance to go barefoot in your spare time.
The temperature changes little, the air is dry and cold, and patients with cardiovascular diseases need anti-static.
Dry cold air is easy to generate static electricity, and people with heart disease or cardiovascular disease had better wear pure cotton underwear. There is static electricity in clothes, which is not a big problem for ordinary people, but patients with heart disease should be careful to get an electric shock. Static electricity sometimes affects ECG conduction, leading to arrhythmia. Therefore, people suffering from heart disease or cardiovascular disease should wear pure cotton underwear, which is both warm and antistatic.
Drinking more water in dry season can prevent static electricity.
"oh! Power is on again. " Xiao Wang was electrocuted when he closed the taxi door. This is his fourth electric shock in one day. According to medical experts, in the current dry season, it is easy to have such a situation, which is the result of the external "discharge" of human static electricity, and frequent "electric shock" indicates that the body is short of water.
According to experts, when the human body is active, the friction between skin and clothes, and the friction between clothes and clothes will generate static electricity. With the increase of household appliances and the increase of people wearing chemical fiber clothes in winter, the electrostatic charges generated by household appliances will be absorbed and accumulated by the human body. In addition, the walls and floors of the room are mostly insulators, and the air is dry, which is more susceptible to electrostatic interference. According to the calculation of professional organizations, reading plastic instructions will produce about 7000 volts of electrostatic interference.
Never think that static electricity has nothing to do with it. Dr. Li from the emergency department of China-Japan Friendship Hospital of Jilin University said that people who have been exposed to computers for a long time will accumulate a lot of static electricity in their bodies, which will lead to pigmentation for a long time; However, because the skin of the elderly is relatively dry than that of the young people, and the cardiovascular system is aging and the anti-interference ability is weakened, the elderly are more susceptible to static electricity and cause cardiovascular diseases.
In order to prevent static electricity, indoor humidity should be maintained, such as sprinkling water or using a humidifier; Take a bath and change clothes frequently to eliminate the static charge accumulated on the surface of human body. When combing your hair, first immerse the comb in water to eliminate static electricity; Touch the wall with your hands after undressing, and touch the wall with your hands before touching the door handle or faucet to discharge static electricity from your body.
Experts pointed out that it is particularly important to generate static electricity, which means that the body is short of water, so you should drink more water at ordinary times to reduce the harm of static electricity to the body.