Static electricity definition: Because the object surface's not balanced electric charge has the shift, to causes the object surface to present surplus or the insufficient static electric charge, calls it the static electricity.

ESD (Electro Static Discharge), namely static discharge's meaning, the static discharge can cause the heat effect of current, is likely the spark (for example causes catches fire with explodes, components puncture or overburning) and electromagnetism field effect (electromagnetic interference).

That what static discharge? The example：
1. Strokes in the family with the hand the cat, you will discover that the cat will bristle with anger unexpectedly.
2. When makes the human body static electricity test we may see “bristles with anger” phenomenon.

3. Severely cold winter, when you take off the warm woolen sweater, you will hear bi bi pa pa the sound (to send out electric discharge sound to be possible to produce are bigger than 5000V the voltage).
4. Dry cold season, when puts out a hand to drive the gate or the window, will feel will receive an electric shock feeling (, when finger will have slight feeling oneself will produce is bigger than 3000V the voltage).

The above these are the phenomena which static electricity instantaneous draining (ESD) leads produces.

The static electricity production way, has the following several ways:

Walk electrification

Triboelectrification

Electrostatic induction electrification

The human body static electricity is mainly by person's motion, including the human body and clothes, the shoes and socks and so on other object friction, the contact, separates, the electrostatic induction or the immediate contact static electricity body produces.

Actually the static electricity will not be by artificial only will then only produce, for example: In the airborne convection's cloud layer, the desert hikes up with the wind granulated substance.

Static electricity harm

The static electricity electric discharge can cause primary device's performance deterioration even to expire, and will disturb the neighbor instrument and equipment's normal work.

The static electricity can cause its hard puncture to primary device's harm, also will cause softly to penetrate the hard puncture will possibly be disposable creates chip dielectric breakdown, overburning and so on permanent the expiration. The soft puncture is refers to ESD to create primary device's performance deterioration or the parameter target drops, therefore penetrates softly the hard puncture hidden danger is bigger.

Completes the static electricity protection three principles to include:

　Principle one: All electric conduction earth.

　Principle two: Turns the anti-static electricity or the static electricity dissipation material 絕 the reason thing.

　Principle three: Maintains certain distance with the sensitive unit, in the principle one and the principle two cannot achieve in the situation uses the principle three

Static electricity control three principles

　Principle one: Stops the electric charge the production.

　Principle two: Prevention static charge memory.

　Principle three: Reduces the electric discharge the speed.

Factory common static electricity measuring apparatus

First, static voltmeter (non-contact type): When gauging with is not measured the object immediate contact, therefore to the testing object electrostatic induction is very small, and will not have the danger which the electric discharge will ignite, in the use a more convenient security, the factory often will use at present this static voltmeter.

Second, human body static electricity production combination tool: Gauging human body static electricity synthesis resistance, including human body, shoes, sock and so on resistance, when the human body synthesis static electricity resistance is bigger than 109~1010 ohm, causes the static electricity not to be able to divulge enters the earth, but has time the static discharge danger, this instrument can demonstrate the red candle caution.

Third, surface impedance measuring instrument

Factory common static electricity protective instrument

Static electricity link: With by the draining human body static electricity, by the static electricity loose and tight bag, the active snap fastener, the spring flexible cord, the protective resistor and the cartridge is composed. The rubber band inner layer by against static electricity yarn knitting, the outer layer weaves with the ordinary yarn, bleeder resistance: 106~107 ohm, the electrostatic potential may weaken in 0.1 second to 100V below.

Matters needing attention：

• • ‧ Maintains with the skin good contact.

  • ‧ The regular test, guaranteed that 1MΩ the resistance contact is good, does not send the opening.

  • ‧ Maintenance good earth.

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  Against static electricity shoes
  

  Puts on against static electricity shoes and uses against static electricity floor (against static electricity ground mat, rug) and against static electricity sock against static electricity shoe pad and so on, can the static electricity from the human body guidance earth: thus 106~107 ohm eliminates the human body static electricity, the shoe sole resistance: 105~108 ohm

  
  Against static electricity shoes
  

  Puts on against static electricity shoes and uses against static electricity floor (against static electricity ground mat, rug) and against static electricity sock against static electricity shoe pad and so on, can the static electricity from the human body guidance earth: thus 106~107 ohm eliminates the human body static electricity, the shoe sole resistance: 105~108 ohm

  
  

  Against static electricity clothes

  The cotton material reeled thread including the certain proportion not 銹 just the textile fiber or the conductive fiber, eliminated on clothing's static electricity by conductive fiber's corona discharge and divulging. Wash number of times: A level > 100 times; B level > 50 times.

• 
  

  Against static electricity glove

  Make with against static electricity cloth or against static electricity knitted fabric use in against static electricity environment which needs the glove to operate. Wash number of times: A level > 100 times; B level > 50 times.

  
  

  Against static electricity shade bag

  Compares with against static electricity bag besides has against static electricity function, but also has the electromagnetism shade function, is composed of the multilayer material, usually is not transparent, the price is higher than against static electricity bag, uses in the packing important static electricity sensitive unit.

  
  Against static electricity air bubble bag

Against static electricity sponge

Against static electricity floor

The conducting material for the stable property the carbon black, the electric conduction network goes nonstop to the undersurface from surface, the parent metal is half flinty PVC plastic, wear-resisting does not get angry, system resistance: 105 ~ 108 ohm.

Against static electricity work chair

Against static electricity work chair

Static electricity table earth

Point discharge

Under strong electric field function, object surface curvature big place (for example incisive, tiny peak), the electric equipotential surfaces is dense, the electric-field intensity sharp increase, causes it nearby air to ionize produces the gaseous discharge, this phenomenon is called the corona discharge. But the point discharge for corona discharge's one kind, refers to nearby the acme the ionization in air to have the gaseous discharge phenomenon specially. Attention: Must avoid the point discharge or the rapid discharge in our work process the influence which brings to the product!

Static electricity standard synopsis

ESD 2001 S11.11

Divides into the object：

EIA541 (static electricity dissipation time test)

To receives measured that the thing exerts the 5000V voltage

Against static electricity indication

Static electricity label sample

Common place

Static electricity area indication

Why can raise the ESD protection consciousness

Before the 1970s, many static electricity questions are because the people do not have ESD to realize create, even if the present will also have many people to create the damage to ESD to the electronic products. This is because the majority ESD harm occur below the human feels, because the human body to static discharge's sensation voltage approximately is 3KV, but many electronic components will even damage in several hundred volts several dozens volts, after usually electronic component by the ESD damage, outward appearance not obvious trace, but will install the part on PCB the function already bad or function Pass but exists the risk which the reliability will drop, regarding this latent damage, the project or the designers will be the use precision instrument is also very difficult to gauge its performance the change, the analysis is also quite difficult.

How to control human body's static electricity (human body static electricity protection)

1. Uses against static electricity floor, against static electricity shoes induct human body's static electricity from the foot the earth.

2. Wears against static electricity link joining-up to induct human body's static electricity from the hand the earth.

The static electricity includes to electronic products' harm form:

1. The static electricity adsorption dust, reduces the part 絕 reason resistance (reduction life).

2. The static discharge destroys, causes the part malfunction (completely destruction).

3. The static discharge electric field or the electric current produce the heat, causes the part to be injured, but the function is normal (latent damage) to create the disturbance or the damage temporarily to the electronic products (electromagnetic interference). If the part is destroyed completely, must be able is small in the production process by Zha Jue and the elimination influence. If part slightly damaged, is not easy under the normal test to discover, because under this situation, the regular session processes many times, even User already when use only then discovers the hypofunction.

4. The static discharge electric field scope is very big, the frequency spectrum extends extremely.