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A2 electric fields - static electricity & earthing Watch

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    Attachment 501277501279Name:  image.jpeg
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Size:  478.3 KBHi,

    I'm having a bit of trouble understanding earthing & charging, and in the both (see the photos), it seems to contract itself. Not quite sure exactly what "earthing" is (Google search didn't seem to give a definitive answer)

    For example with the microchips;

    If when the pins are touched and become earthed, surely this means they now become uncharged? So no longer remain charged as it says?

    Thanks
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    (Original post by JohnnyDavidson)
    Attachment 501277501279Name:  image.jpeg
Views: 49
Size:  478.3 KBHi,

    I'm having a bit of trouble understanding earthing & charging, and in the both (see the photos), it seems to contract itself. Not quite sure exactly what "earthing" is (Google search didn't seem to give a definitive answer)

    For example with the microchips;

    If when the pins are touched and become earthed, surely this means they now become uncharged? So no longer remain charged as it says?

    Thanks
    The wording in the text is poor making it ambiguous.

    It's trying to say:

    The Earth (planet) can be considered as an infinite source or sink of electrons and as such is the reference for all other charges. Because it so overwhelmingly massive in comparison to anything else (including clouds) any charge build up on an object will try to flow back to the earth as a current through the lowest resistance conduction path.

    Earthing or grounding literally means creating a conduction path to the earth.

    Semiconductors or Very Large Scale Integrated Circuits (VLSI microchips) can easily be destroyed by even small amounts of current discharging to anything that creates a conduction path if a charge build up is allowed to occur.

    Charge build up can be caused by handling an isolated/insulated device and when a conduction path is created (such as when a person touches the pins) the different charges try to equalise (different voltage potentials) and a current is created. That means including conduction paths from the pins to earth if a charge is allowed to build up on the pins which is not earth potential.

    The way to prevent such damage is to never allow the build up of charge either more positive or more negative than earth potential. i.e. the devices are manufactured in strict conditions with all manufacturing processes at earth potential.

    When the manufacturing process is complete, the devices are stored in protective anti-static bags which first and foremost prevent the build up of charge by dissipating charges to the atmosphere or ground long before they reach a damaging potential.

    It means that handling devices must always be carried out at an earthed or grounded workstation since both the device and anything it then comes into contact with are at the same voltage potential and no current can flow.
 
 
 
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