MKS Novx 5000 Series, Руководство пользователя

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19-5000-M Version 1 20 Voltage Detection System Series 5000
8.1.3 Conduction Charging
Conduction Charging occurs when two conducting bodies, one with a
charge, and a second one without a charge, or with a different charge, are
brought into contact, either by touching each other or by establishing a
conductive path between the bodies. The charge which existed on the first
body will, after contact, be redistributed across both bodies, and the
originally uncharged body will have taken on a certain fraction of the initial
charge of the first body.
An example of conduction charging is when a charged human being
touches an isolated conducting object such as a metal container with
explosive powder. Depending on the amount of charge in the human
body, arcing may or may not occur at the moment contact is made; but in
both cases a fraction of the charge, originally stored in the human body,
will have been transferred (possibly with a bang) to the metal container.
In the practical world, Triboelectrification, Induction Charging and
Conduction Charging are closely intertwined and sometimes difficult to
distinguish.
For example, a person wearing insulating shoes and walking over an
insulating surface such as carpet, will cause triboelectrification in the shoe
soles. Charge will be trapped at the bottom surface of the shoe sole (the
surface in contact with the carpet). Since the human body can be
considered as a conductor, the trapped charge in the insulated shoe sole
will induce polarization of charge in the human body.
If the person then touches a grounded conductor, whether a hard ground
or one with a high series resistance such as the input probe of a
instrument, a charge will be drawn from the earth. This is an attempt to
neutralize the polarized charge on the human body, and the body will be
left with a charge equal in magnitude but opposite in polarity to the charge
trapped in the shoe soles. In this case, both triboelectrification and
induction charging have taken place.
Another example is a person wearing conductive shoes or an ESD ground
strap, walking over an isolated surface. In this case, the charging
mechanism is triboelectrification between an insulator (the carpet) and a
conductor (the person, including shoes).