CAR 66 Module 5.12 Electrostatics Sensitive Device

7/31/2019 CAR 66 Module 5.12 Electrostatics Sensitive Device

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ESD

Electrostatic Sensitive Devices (ESD) are

electronic components and other parts that are

prone to damage from stray electric charge.

Extensive (and permanent) damage to static

sensitive devices can result from mishandling andinappropriate methods of storage and

transportation.


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STATIC ELECTRICITY

When two dissimilar, initially uncharged non-conducting materials are rubbed together, the frictionis responsible in transferring charge from one material

to.

The process of electron transfer known as'triboelectric charging'.

The amount of charge depends on factors like the rateof separation, humidity etc.


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POSITIVE TRIBOELECTRIC

The following materials give up electrons and become positive when charged whenrubbed against other materials:

Air (most positive)

Dry human skin

Leather

Rabbit fur

Glass

Human hair

Nylon

Wool

Lead

Cat fur

Silk

Aluminium

Paper (least positive).


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NEGATIVE TRIBOELECTRIC

The following materials tend to attract electrons when rubbed against other materialsand become negative when charged:

Wood (least negative)

Amber

Hard rubber

Nickel, copper, brass & silver

Gold and platinum

Polyester

Polystyrene

Saran

Polyurethane

Polyethylene

Polypropylene

Polyvinylchloride (PVC)

Silicon Teflon (most negative)


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VALUE ELECTROSTATIC


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CAUSES ESD

Electrostatic discharge from a human body

charged material to the ESDS device. Electrostatic discharge from the device

Field induced discharges


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ESD WARNING


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HANDLING ESD EQUIPMENT

Placards installed on the ESD LRU

The ESD printed circuit boards are identified with astatic sensitive placard.

Contaminated or unwanted material should be keptclear of the sensitive devices.

Connect the wrist strap into the Electrostatic GroundJack of the card file or recognised aircraft ESD ground

point. LRU or circuit boards are to be placed in the correct

conductive bag or container which must display an ESDlabel.


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TRANSPORTING ESD EQUIPMENT

1. Use of wrist straps which must be worn when handling ESD

2. Use a heel strap

3. Use of static dissipative floor and bench mats.

4. Avoidance of very dry environments

5. Availability of ground jacks6. Use of grounded test equipment

7. Use of low-voltage soldering equipment and anti-staticsoldering stations

8. Use of anti-static insertion and removal tools for integratedcircuits.

9. Avoidance of nearby high-voltage sources

10.Use of anti-static packaging


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WRIST STRIP

CAR 66 Module 5.12 Electrostatics Sensitive Device

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