Engineering Specification
ES-3U5T-1B257-AA
EMC Design Guide for Printed Circuit Boards
Frame 35 of 78
Rev. A
10/01/2002
Printed copies are uncontrolled
0
0.1
0.2
0.3
0.4
0.5
0.1
1
10
100
h/d
L
gr
(microhenrys/foot)
Figure 314. Mutual Inductance Between Two Wires
Equation 315 gives induced noise voltage from inductive coupling:
dt
di
L
N
g
gr
noise
×
=
Equation 315. Noise voltage due to inductive coupling
Where,
dt
di
g
is the rate of change of the generator current
Therefore, fast changing generator currents will induce larger noise voltages in
receptor circuits.
Equation 316 also gives the noise voltage due to inductive coupling:
cos
BA
j
V
n
×
=
Equation 316. Noise voltage due to inductive coupling
Where, B is the magnetic flux density (weber/cm
2
)
A is the receptor circuit area (cm
2
)
is the angle between the generator and receptor circuit
Summary :
Noise voltage due to inductive coupling Where, dt di g is the rate of change of the generator current Therefore, fast changing generator currents will induce larger noise voltages in receptor circuits.
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noise,coupling,oltage,equation,inductie,receptor,due,circuit,generator,gies,printed,315,between