Desco - Questions And Answers

If two charged dielectric materials, of opposite or same polarity, are brought to close proximity of each other, will there be a transfer of charge from one material to the other. And, does the introduction (contact) of a reference ground impact the decay time of the ESC on these materials? - Anonymous, San Jose, CA

If two charged dielectrics (insulators) are brought into near proximity or contact, typically there will not be a transfer of charge (free electrons) from or to either because they are very poor conductors. If the charge imbalance is concentrated in a small area and the corresponding electric field is rather substantial, then there is a chance that the air will become a conductor and a breakdown will occur. More common with dielectrics holding large electric fields is that the field is more deadly to an ESDS device then an ESD event may be. The electric field emanating from the external dielectric (e.g., styrofoam cup) can cause the dielectric inside the ESDS device (SiO2) to breakdown (burn holes, or cause the circuit to fail). Bringing a reference ground in near proximity or contact to the charged dielectric may suppress part of the field (cause it’s magnitude to be temporarily reduced) but will not discharge the charge imbalance or have much of an effect on the decay time of the charge imbalance.

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