Weak current College】 【anti-static knowledge (6)】.

60. q: will ESD flooring system attached to the housing lighting protection or grounding system, do you?
A: we strongly recommend to electrostatic discharge grounding system and housing lighting protection system is connected to. Typically, the lighting, grounding system has a direct and individual paths, and there are no sudden turning angle of the wire. When lighting is broken, this path will have a lot of pulses, if ESD grounding system also in this path, be sure to make the lighting circuit and grounding/earthing circuit housing isolated from the Earth. They can be connected at the same point received housing outside 8 foot long grounding rods, the path should be independent of each other. Shall be composed of professional electrical technicians inspect, at the same time managing the electrical code.

61. q: we have a level of clean tent 10000, in its interior, we intend to build a research space. This device is based on optical principles of design, particle and degassing effect is very sensitive. Tent in much email, I want to know the clean room and electrostatic loss request should use the best materials?

A: the best clean indoor use is the floor mat L models. Each roll width 0.60cm, long 122m, in clean room requirements, application to connect to the wrist set of floor mats, these materials can be ordered from the manufacturer.

62. q: we discovered the magnetic effect. At work, we are in electrostatic discharge environments, work clothes, footwear, wrist sets, chairs, ion generator, almost everything with static electricity. We would like to know what to wear these with magnetic insoles for shoes is the production of the finished product will be corrupted. We at air room installed electronic sensor component, magnetic on so many people, so we do not want to give up. Any information would greatly be appreciated. On?

A: what you say has the effect of magnetic insoles does not interfere with electrostatic discharge procedure. The only exception is if the electrode Head Office of the magnetic field is so strong that your feet are also very slowly over a low-impedance conductor, then you will generate the current, if you let the energy cannot release will cause failure, over time, cause the accumulation of discharging electricity to a very high level.

63, q: after the adoption of MIL-883 model, we found a different scenario, when the shield symbol from shielding bag removal, it will be static discharge damage. I am also looking for this book, which is the electrostatic discharge bag of components in the protection of State work, which leads to short. How to explain this phenomenon?

A: when the shield symbol from shielding bag removal, it may be damaged. Generated electrostatic charge can be an object (like a shielding bag symbol), you can move from static discharge. When ordering shielding bags you need to specify the antistatic characteristics parameters. Antistatic refers to material by frictional charge.

64. q: I'm trying to find and match company MIL-W-80 standards, this is a static loss of acrylic fiber or acrylic coating related 1966MIL standards. Please give a detailed description.

A: MIL-W-80 refers to sheet or strip of solid substances, cannot be applied to the floor coating. Floor coating with several industry-recognized standard (ANSI/ESD-S7.1 floor coating surface impedance standards AATCCTM-134-1979 is floor coating, electrostatic standards, M-4046 FTMS101C is floor coating of charge attenuation standard).

65. q: my company is a manufacturer of computer, their reliability test of electrostatic discharge. The test used by the standard is IEC-810-4L3, air: 8kV, lap voltage: 6kV. But we want to sell to a purchase of California United States. How to test for electrostatic discharge voltage when the number of kV?

A: in testing electrostatic discharge-sensitive, the test method has the following three:
1. the human body model (+ 4000V and-4000V voltage waveform, 0 and 500 load)
2. charge component model (you can reach the voltage waveform 2000V)
3. mechanical model (+ 400V and-400V voltage waveform, 0 and 500 load)
This includes the voltage limit, note under different load impedance, there will be different waveform requirements. In the United States Marlboro, Massachusetts, in Rome, New York electrostatic discharge Association, these standard for electrostatic discharge system is effective.

66. q: I have a dry powder fire extinguishers, when the powder is a spiral conveyor up squeeze, it through a metal detector into a diameter 15.2cm, long stainless steel tube 91cm. When firefighters at the touch of fire extinguishers can occur when the lid is electrostatic discharge phenomena. We strive to bring all metal parts are connected to the same single-point grounding, and placed on the floor a antistatic mat. Firefighters are 100% cotton clothing, body so that you can move and do not need to bring this wrist-set, any good suggestions?

A: when dry through stainless steel pipes and filled with dry powder fire extinguishers, fire extinguishers and are generating friction electric. Operations personnel are most likely to feel the electrostatic discharge electricity is caused as a result of this process. You can try all the metal parts with a single point of grounding (CPG) connect and use antistatic floor mat. You've taken a number of important electrostatic discharge control program, but still does not solve your problem. You need to check the following points:
The cover should be 1, fire extinguishers and conducting with the same single-point grounding connection.
2. fire extinguisher should be used in the shell, with the same single-point grounding connection.
3. If both are not be used, then you should consider using ionizing.
4, antistatic floor mats can be conductive or loss of, and should be connected to the same single-point grounding.
5. all the exercisesThe staff should wear a pair of 2 m anti-static shoes, and connected with conductive ground covers, so that they don't cover the Fire Department became the electrostatic discharge event of the excitation source.
Just follow these steps to perform correctly, it should be under control.

67. q: recently, I used two pieces with a different charge of metal plate (a small piece of a larger and rules) that charge plate Analyzer inspection ion beam, in the same region and ion beam spacing between two ways of reading sample and found a small piece of approximately 6V, and larger piece of the indication for-8V. When you try to make the same ion beam spacing, I take what a value when testing the metal plate readings appears as +/-X Volt, this is the representative of the total voltage of X% or charge with detecting? (for example, 1500V 1% or 1% of 8V?)

A: first of all, on the charge-sheet analysis instrument two block individually check to be calibrated to ensure its accuracy. Second, verify accuracy of product specifications. Third, it can be a different charge plate area. Ion beam along the axial length several emission source, make sure you are in the same distance and cover the same area. If the emission source DC and every inch of its polarity change once you are measuring is due to the location of the charge-sheet. Accuracy should charge plate measuring out the voltage reading. Check the product data to confirm that it can be applied to your cell circuit.

68. q: factory production shop floor most of all have a layer of tiles, static electricity loss but there are also some corner is not paved. The floor is a concrete structure, I'd like to know which have sufficient loss of? the floor coating with a layer of wax such as conductive coatings such as conductive will play a role?

A: separate concrete does not form a complete ESD flooring. Even on the floor, groundwater seeps through infiltration exports, making the concrete conductive, but there are always some dry and wet inconsistencies. Obviously, the conductive silicon chip wax is a useful, we'd better be conductive coating of wax as a floor, because there are no wax coated, and wax are insulated. The floor wax, you should be careful of concrete floor cover to avoid water problems caused by poor bonding, and this can increase the coverage of floor coatings (by reducing floor of porosity). Other solutions are: to give concrete floor coating with a layer of conductive lacquer; conductive ceramic tile or floor mat; divided conductive carpet or laying out a region as non-electrostatic discharge zone.

69. q: I anti-static shoes very interested, but not clear electrostatic discharge floor must have something or is manual. If you want to try flooring electrostatic discharge plasticity, what measures must be taken, please give some advice, in addition, the floor meets the demands of the specific implementation of the programme?

A: according to the standard EIA-625, ESD flooring of resistance should be greater than 105 and 109. Electrostatic discharge Association has a pilot standard ESDDSTM54.1-1997, in the measurement of resistance, flooring and footwear items merging together. This actually is a measurement method, does not provide or recommend working in resistive interval. In fact, in order to test floor, standard ANSI/ESD-S7.1-1994 there is a clear test methods, that is, with two five-point probe driving voltage 10V or 100V. Use of the instrument is the specialized model 41273 doing this kind of measurement.

70. q: CMOS integrated chip in to withstand severe leakage of electrostatic discharge, electrical shock reliability will downgrade?

Answer: If the path includes the electricity leakage CMOS device input (needle can Soldered joints) end, so when one of the strong electrostatic discharge will enable CMOS cell circuit instability phenomena. This makes the life of the associated components and can produce shorter batch failures. You can open the faulty component package, and place it in the power microscope or scanning electron micrograph, you can see the damaged area.