# EMC CAPACITIVE COUPLING BETWEEN CONDUCTORS

I am looking for some help with the attached problem, I have a number of similar problems to work through so if I could get a detailed solution to this problem it would greatly help my understanding and approach to my other problems.

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#### Solution Preview

I will address the descriptive parts of this posting by means of an update in the next few hours. I wanted to get the calculative solution off to you quickly as I noticed the posting due to expire within the next hour

The above can be redrawn more formally as two parallel networks connected together by the mutual capacitance as shown below

As no source resistance is specified we set R_S=0Î© so that all the source voltage appears across the input network. Also since no secondary circuit source voltage is specified we set V_S2=0 as shown by the modified circuit below

We now find the parallel combination of R=R_2 ||R_L2 in the secondary network from

R=R_2 ||R_L2=(1/R_2 +1/R_L2 )^(-1)

R=R_2 ||R_L2=(1/1000+1/2000)^(-1)=667Î©

Then we can replace both R_2 and R_L2 by a single equivalent resistor Ras shown below

The above circuit is simply a voltage divider circuit with two complex impedances denoted by Z_12 and Z_2 as shown

We use circuit theory to derive the magnitude of the impedances at a angular frequency Ï‰ as shown below

Z_12=1/(jÏ‰C_12 )=-j 1/(Ï‰RC_12 )

Which has magnitude

|Z_12 |=1/(Ï‰RC_12 )

Also

Z_2=(1/R+1/(1/jÏ‰C_22 ))^(-1)=((1+jÏ‰RC_22)/R)^(-1)

Z_2=R/(1+jÏ‰RC_22 )=(R(1-jÏ‰RC_22))/(1+(Ï‰RC_22 )^2 )

Thus

Z_2+Z_12=(R(1-jÏ‰RC_22))/(1+(Ï‰RC_22 )^2 )-j 1/(Ï‰RC_12 )

Z_2+Z_12=R/(1+(Ï‰RC_22 )^2 )-j{(Ï‰R^2 C_22.Ï‰RC_12+1+(Ï‰RC_22 )^2)/({1+(Ï‰RC_22 )^2}Ï‰RC_12 )}

Z_2+Z_12=(Ï‰R^2 C_12-j{Ï‰^2 R^3 C_22.C_12+1+(Ï‰RC_22 )^2})/({1+(Ï‰RC_22 )^2}Ï‰RC_12 )

Which has ...

#### Solution Summary

EMC calculation of crosstalk voltage induced in victim conductor due to capacitive coupling between conductors are examined.