EECS
2015+1-1,2,3+all.pdf

3 can put electric charges only on insulators 4 can

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3. Can put electric charges only on insulators. 4. Can cause sparks. The false statements are: A. Only 1 B. 1 and 2 C. 1. 2, and 3 D. 3 and 4 E. All on the list. Answer to this problem is at the end of the Unit. Book Page 144
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EE for 21 st century 1-3 Prevent electrostatic discharge 1-3-1 Hazards of ESD for EE © 2015 Alexander Ganago Page 22 of 23 Last printed 2015-07-24 6:00 PM File: 2015 1-3-1 ESD.docx K EY CONCEPTS , OR S UMMARY OF NEW LEARNING v The elementary positive charge (of a proton) equals 1.602 · 10 -19 C. The elementary negative charge (of an electron) has the exactly same magnitude. v Triboelectric effect or charging occurs when two materials are brought in close contact and then separated. v Triboelectric series is a list of materials sorted according to the sign and magnitude of static electric charges that they accumulate due to rubbing. v The universal principle of the conservation of electric charges maintains that the net charge of a closed system remains unchanged. It means that electric charges can be separated and/or recombined but never created or destroyed. v Conductors and insulators, as well as water, air, and dust particles in the air can bear electrostatic charges. v By simple everyday actions such as walking across carpet, one can easily accumulate static electric charges that generate voltages up 35,000 V. v The voltages generated by static electric charges get lower if the air is humid. v Electrostatic discharge (ESD) is the transfer of charge between bodies at different electric potentials. v Voltages as low as 100 V can cause ESD damage to electronic devices. v ESD damage to electronic devices may be catastrophic or latent. v An electronic device damaged by ESD may cause failure of the product where it is installed. v Two main strategies for ESD prevention are: I. Prevent accumulation of static electric charges at the workplace. II. Remove from the workplace the electric charges, which are already accumulated there. v Conductive materials have low electrical resistance: their electrons can freely flow across the volume or surface of such materials. v Ground is an electric connection to Mother Earth, which has zero electric potential. v Static electric charges can be removed from conductors by grounding. v Static electric charges can be removed from the human body by grounding via wrist straps, heel and toe attachments to shoes, etc. v Insulative materials have high electric resistances because electrons cannot freely move across their volume and surface. v Grounding does not remove static electric charges from insulators. v Air ionizers and humidifiers help to remove static electric charges from insulators. v Electric resistances of static dissipative materials are between those of insulators and conductors. v Static dissipative materials are specially designed for the removal of static electric charges and are manufactured in many forms, including wrist straps, desk mats, and floor tiles.
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  • Fall '07
  • Ganago
  • Electric charge, Alexander Ganago

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