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VDG and computers




Oh, got a suggestion for you all - if you are doing a science show
for a grand opening of a super-maga electonics/computer/etc. store
like Incredible Universe, don't do the Van de Graaff thing next
to the computer control that contols EVERYTHING in the store,

Hey, that reminds me of something I've talked about but never written
down. I should add to my VDG web page. Is the following a little
overly-paranoid?


VDG VERSUS PC

A VDG is a constant current source. During normal operation there is
a large e-field around the device, but there is also a flow of charge
between the sphere and ground. This flow is composed of charged
air, and while some of it manages to get to ground, much of it
is attracted to surfaces, and lots of it travels far beyond the
region immediately around the machine. If the humidity is low, it will
build up on insulating surfaces where it creates large e-fields and
high voltages. In other words, an operating VandeGraaff SPEWS CHARGED
WIND which wanders around charging up EVERYTHING in the room, including
the walls, ceilings, people, etc. The fans on your PC will suck the
charged air into the case, where it will electrify all non-metal surfaces,
cause huge electrostatic fields and sudden sparks, and generally trash
circuitry left and right. It also tends to collect on ungrounded
plastic parts such as keyboards. It is wise to avoid doing VDG demos
in the same room with an operating computer. If this cannot be avoided,
then keep your demo short, keep the VDG as far as possible from your
computer, VCR, etc., keep the VDG turned off or shorted with a ground
clip except during actual use, and avoid days with extremely low
humidity. Better yet, do a Tesla coil demo instead!


......................uuuu / oo \ uuuu........,.............................
William Beaty voice:206-781-3320 bbs:206-789-0775 cserv:71241,3623
EE/Programmer/Science exhibit designer http://www.eskimo.com/~billb/
Seattle, WA 98117 billb@eskimo.com SCIENCE HOBBYIST web page