[SOLVED] in s domain is s a frequency

[Hassan Munir]

how to solve for reactive component knowing a zero occurs at a particular frequency

So i have the following problem

How do i solve for a specific component given that the a zero occurs at a particular frequency

so the numerator of my Transfer function is "R3(sC2L1 +1)" and I am told that a zero occurs at 2.7 MHz

I know the values of R3 and C2, the only component I am missing is the inductance L1

my initial go at this was to set s=jw , w=2*pi*f , and set the above numerator to zero to solve for inductance however I get stuck here

L= -1/(jwC2) which doesn't make sense since inductance is not complex(I know reactance is) and it can't be negative.

So how I get solve for L1 using the information I know.

Please help

 

[albbg]

Are you sure about the transfer function ? The dimension of sC2L2 is pF; probably the correct expression is s^2C2L2 that is dimensionless (unless the "1" of sC2L2+1 is pF). If it is so:

-w^2*C2*L2+1 = 0 ==> L2=1/(w^2*C2)

 

[goldsmith]

Dear Hassan Munir
Hi
Has you problem any circuit ?
And what do you mean by "L= -1/(jwC2)" ??!
If you tell me a bit more explanation , perhaps i can help you .
Best Wishes
Goldsmith

 

[Hassan Munir]

Thank you albbg!

You are correct I actually missed the extra s in my calculation and now i got s^2 in the numerator

cheers,

 

[v_c]

s is in rad/s (angular frequency). The factors 1/(RC), R/L and 1/sqrt(LC) are also in rad/s. sqrt(L/C) is in ohms.