What circuits do you need to have electrostatic protection circuits? What are the principles?

Electrostatic protection circuits mainly study electrostatic application technologies, such as electrostatic precipitation, electrostatic copying, electrostatic biological effects, etc. In recent years, with the rapid development of science and technology, the wide application of microelectronics technology and the increasingly complex electromagnetic environment, the electromagnetic field effect of electrostatic discharge, such as electromagnetic interference (EMI) and electromagnetic compatibility (EMC), has become an urgent problem to be solved. On the one hand, the wide application of some polymer materials with high resistivity such as plastics, rubber and other products and the high-speed of modern production processes have made the accumulation of electrostatic energy to a very high degree, on the other hand, the production and use of electrostatic sensitive materials, such as light oil, gunpowder, solid-state electronic devices, etc., the industrial and mining enterprise sector is also more and more prominent by the harm of static electricity, and the electrostatic hazard has caused quite serious consequences and losses.

It can inadvertently break down expensive electronic components, costing the electronics industry tens of billions of dollars a year. In Xinghang Industry, electrostatic discharge caused rocket and satellite launch failures, interfering with the operation of Xinghang aircraft. On July 29, 1967, a serious accident occurred on board the American aircraft carrier Forrestal, a missile on an A4 aircraft suddenly ignited, causing $72 million in damage and injuring 134 people.

At the end of 1969, in less than a month, the static electricity generated by the washing of three 200,000-ton supertankers in the Netherlands, Norway and the United Kingdom occurred one after another**.

Small signal UV and input, CPU, DSP, chips operating at low voltage, insulated gate FET, and high-frequency tubes above 1G all need to be protected against electrostatic electricity. The natural world, including the human body's own activities, carries different electrostatic voltages. When people come into contact with these arrogant components, they often cause unintentional damage.

Therefore, in production, the hand is covered with an anti-static metal discharge ring.

There is no essential difference between "static electricity" and kinetic electricity (electricity in daily life), but in places with high dielectric strength and capacitance, charges are formed by accumulation, which can be generated by friction and induction. The damage to the circuit is very serious.

In the circuit, the general measures are taken to prevent external static interference.

1 welding: take production line grounding, personnel grounding, humidification, and other methods to reduce static energy aggregation 2 circuit: line entry point to take filtering, add discharge tubes, TVS tubes, varistors, voltage stabilizer tubes, inductors, etc., to reduce the high-voltage pulse interference introduced by the line.

3 components: use tested components (integrated circuits) that can pass high-voltage tests 4 power supply: take the primary capacitance, resistance method, grounding, etc. to remove the accumulated static electricity.

That's right. <>

Static electricity can cause fire and fire, especially in petroleum, chemical, rubber, paper printing, powder processing and other industries. Electrostatic shocks can occur when a human body is in close proximity to a live object, or when a electrostatic human body is near a grounded conductor or other conductor. If the static electricity is not removed from the lead in the production process, it will often hinder the production or reduce the quality of the products, such as:

The sieve holes are blocked, the textile yarns are tangled, and the handwriting of the printed matter is uneven; Semiconductor and electronic components are damaged or malfunctioned due to the discharge current, resulting in the scrapping of photographic films.

There are many protective measures against static electricity, and the more common ones are grounding through bracelets, clothing, anti-static shoes and other measures; It is mainly to use static dissipative materials to replace the good materials of ordinary cave cars; Use closed conductors to shield static power sources or products that need to be protected; Antistatic agents are used to increase electrical conductivity, so that static electricity is easy to leak; Spraying, sprinkling and other methods are used to increase the relative humidity of the environment to 60 to 70% to suppress the generation of static electricity.

Answers]: c, d, e

Reduced oxidant content.

Fill with nitrogen, carbon dioxide or other inactive gases to reduce the oxygen content in ** gases, vapors or ** dusts to eliminate combustion conditions. When the oxygen content of the mixture does not exceed 8, it will not cause combustion. a Wrong wheel section;

Limit the speed of movement of the material.

In order to limit the generation of dangerous static electricity, the crane tube should be 200 mm deep into the bottom of the tank when the top oil is used for car tankers. When the oil tank is filled with oil, the initial flow rate should not be greater than 1m s, when the injection port is immersed in 200mm, the flow rate can be gradually increased, but the maximum flow rate should not exceed 7m error;

Electrostatic grounding. Automobile tankers and railway tankers should be connected and grounded with oil storage equipment before loading oil; After loading and unloading, the tubing is dismantled first, and then the jumper line and grounding trap line are removed.

c Correct; The relative humidity of the local environment should be increased to more than 50. The function of humidification is mainly to enhance the leakage of static electricity along the surface of the insulator. d Correct;

Electrostatic neutralizer.

Also known as a static eliminator. Use the wax ruler Yu electrostatic neutralizer to neutralize the static electricity on the charged object by allowing the ions with opposite polarity of the electrostatic charge on the charged object to reduce the charged charge on the object. e correct.

The three basic bases of anti-static are bai

There are three ways to prevent the accumulation of electrostatic charges: First.

DAO grounding, that is, directing the version of static electricity to the earth; The second is the right electrostatic shielding, which is to use the method of electrostatic shielding to weaken the influence of external static electricity on the components; The third is ion neutralization, that is, the electrostatic charge is neutralized with ions of opposite polarity. These three methods are used to continuously introduce electrostatic charges into the earth, shield or neutralize electrostatic electricity, and control the electrostatic potential within a safe range. It's a way to prevent.

1 All A In order to prevent the static electricity phenomenon of the human body, it can keep the ** moist, so a is wrong; b Racing tires are made of conductive rubber in order to send electrostatic current to the earth, so B is wrong; The function of the lightning rod is to guide the charged cloud to discharge through the metal wire, so C error D is correct; Therefore, choose D