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ground the shield at any other point because it is not thick enough to withstand
current running through it.
Magnetic induction comes from magnetic fields surrounding the flow of current.
The fields produce current in the signal wires which generates noise. You can
reduce the amount of magnetic induction by using twisted-pair wire. The more
twists per length of wire, the more the magnetic interference is reduced.
Transients, also called voltage spikes, can be induced on signal wires by
sources such as lightning strikes. If your signal wires are in an environment
susceptible to lightning strikes or other sources of transients, run the wires
through a metal conduit grounded in several places or through a thick shield
grounded in several places.
Note
A foil shield is not thick enough to protect against transients and
should be grounded only at one end.
1
Twisted pair
2
Foil shield
3
Conduit
4
Grounded
in several
locations
5
Grounded
at one end
©
National Instruments Corporation
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FP-20xx Quick Start Guide
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