Interview question on transmission lines

[praveen450]

Hi,

I am going through interview questions online and I found this question. Can anyone give me an answer


Consider a transmission line with characteristic impedance Z?. This transmission line is terminated in Zo. The input impedance is

(A) 4 Z
(B) 2 Z
(C) Z
(D) Z /2

 

[barry]

I believe the correct answer is C.

 

[BigBoss]

Hi,

I am going through interview questions online and I found this question. Can anyone give me an answer


Consider a transmission line with characteristic impedance Z?. This transmission line is terminated in Zo. The input impedance is

(A) 4 Z
(B) 2 Z
(C) Z
(D) Z /2

Question is not complete ?? Of course the answer is neither if the Zc is different than ZL..
A transmission line with a characteristic impedance Zc that is loaded by ZL will show an impedance at its input that varies with its length.

 

[praveen450]

That is the question and they haven't given any transmission line length. I recently had an interview where they asked me the same type of question

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Your answer is right. Can you tell me how you got it

 

[FvM]

Question is not complete ?? Of course the answer is neither if the Zc is different than ZL.

Right. The question makes only sense if Z = Zo. Most likely the question was quoted incorrectly.

Can you tell me how you got it

E.g. by reading a text book. See "matched load" paragraph in this article.
https://en.wikipedia.org/wiki/Transmission_line#Matched_load