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Electrstatic Discharge
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- 2. Objectives: What IsElectrostatic Discharge (ESD)? Principles ◦ Triboelectrification ◦ Charging by Induction Factors effecting ESD Prevention of ESD
- 3. The Electrostatic Discharge is defined asthe sudden transfer of electro static charges between bodies at different potentials caused by direct contact or WHAT IS ESD?
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- 5. Triboelectrification A typeof contact electrification. Charging of bodies due to the fictive contact.
- 6. Triboelectric Series: Human hairget positively charged if it is combed by a hard rubber comb.
- 7. When two materialsare in intimate contact, they share electrons which are at their surfaces. When materials are in contact It is possible for electrons to be “stolen” from one material by nuclei in the other material, because they have a stronger force
- 8. When these materialsare separated, electrons are removed from one material and are transferred to the other material. When the materials are separated Electrons “lost” Electrons “gained”
- 9. Charging by induction Thepresence of this very strong force causes similar charges on the surfaces of nearby conductors to be repelled. The charge imbalance on a surface produces an electric field.
- 10. Charging by induction Ifthe conductor is grounded while it is still influenced by the electric field, these repelled charges go to earth, thus maintaining a charge balance in the areas of the conductor that are not affected by the electric field.
- 11. FACTORS: •Type of Material •RelativeHumidity •Posture of body •Type of cloth •Body resistance
- 12. A person whowalks across a synthetic carpet gets triboelectrified with positive charge.
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Editor's Notes
- #2 Today, I am going to discuss about Electrostatic discharge – which is a serious threat to the electronic devices. This is one of the major problems to be prevented completely. Ignorance of electrostatic discharge may lead to many catastrophic disasters.
- #3 Main objectives of this seminar is to improve your awareness on electrostatic discharge. Today, I would like to tell you about: What is RSD. Reasons for ESD Factors effecting ESD Damage due to ESD Preventing
- #4 ESD: It is the SUDDEN electrostatic discharge between the bodies of different potentials. This transfer may be due to physical contact, Or may be without any contact Or may be due to fictive contact between the two bodies.
- #5 The two basic principles are triboelectrification and charging by induction.
- #6 This is a type of contact electrification. When there exists a fictive contact between two bodies, i.e., when two bodies are rubbed with each other. Then both of them will acquire some charge. The polarity of the charge acquired by a body depends on its relative position in triboelectric series.
- #7 This is the triboelectric series. If two materials are rubbed with each other, then the material which is in the relatively higher position in the series will be positively charged. The other material gets negative charge.
- #8 Now let us look into it in depth. When two materials are in contact, then there is electron sharing between some of the atoms. By this, one material loses electrons and the other gains. Hence charges are generated in both bodies.
- #10 Generation of charges may not require any physical contact between the bodies. When there is a charge imbalance on a surface, then electric fiels will be generated. This generated electric field will repel the charges in that region. This may lead to damage of the whole device. Proper earthing may avoid this.
- #12 It depends on the type of the material i.e., its position in triboelectric series. Relative humidity: If the moisture content in air is more.
- #13 Now, let me give u a real time example for this ESD. When a person walks on a synthetic carpet, a charge imbalance is created in the sole of the shoe. This unbalanced charge enables elctric field into the foot. This electric field repels the charge into our body. Thus our body gets charged. At this moment, if our body touches a metal like door knob, we can experience ESD. Charge in our body will be transfered to doorknob. Thus ESD occurs. If it is a door knob, It may not lead to a huge effect. But , if it is IC, it may lead lead to huge catastrophic effects. If a person who walked on the synthetic carpet, touches any electronic
- #14 By using these anti static bags for the storage of IC’s instead of simple plastic bags. By keeping the floor mat in fabrication plants, By wearing the wrist or ankle straps – we can reduce this ESD effect.