Help me find the y-parameters for this network

[renzworldc]

Hello all,
Plz find the y-parameters(Y11,Y12,Y21,Y21) for the network shown.
n also whats the significance of this parameter..?? :!:

 

[renzworldc]

y-parameters

I hav done star-delta transformation.. and after that I get it this way.. now how to find the Y-parameters??

 

[tyassin]

y parameter

Hi

You can look up the definitions of the y-paramters.
As a starter to find Y11(Input admittance at port 1). You short port 2(V2=0). Then you find the ratio between the input current(I1) over the input voltage(V1).

 

[renzworldc]

y-parameter

well I know the def. of the ratios... but if u can just give me an answer... I mean the numerical value of each parameters wrt the circuit, wud b helpful .. I cud verify with my ans...

 

[tyassin]

finding y parameters

First circuit:
Y11=Y22=3/2
Y21=Y12=-1/6

Second circuit:
Y11=Y22=3/2
Y21==Y12=-1/2

 

[renzworldc]

y view parameters

thanks for ur rply... but actually I hav to find Y-para for the 1st circuit... for that I did a star-delta conversion for ease.. n got the 2nd one...
Since u are getting two diffrnt ans for the same question... dat means doing the transformation isnt correct..!!
do reply..
Regards.

 

[tyassin]

the y parameters

Hi

yes I have made an error.
The correct answer for the first circuit is
Y21=Y12=-1/2

So yes they are the same.

Regards

 

[renzworldc]

determining the y parameters

ok thanks tyassin,
even I get -1/2 as the answer.. but in my exam I was asked this question and the options for Y21 were
1/3, -1/3, 1/6, -1/6.
They didnt give an option for -1/2.
So do u think we can come to a conclusion that the options were incorrect or there is still somthing wrong wid our calculation..??

 

[starfire_v2]

y parameters of a circuit

Hope this might help you

http://sureshks.netfirms.com/book/two_ports.pdf