# The Y , h , Z-parameters

Thread Starter

#### Rio

Joined Dec 23, 2010
22
hey guys
i need your help once again ,, this time in defining the h y and z parameters with circuits that has a depended current source and a depended voltage source and i hope u can help me find answers to the following problems with the equations and how to get to the final one and Thank you #### t_n_k

Joined Mar 6, 2009
5,455
You should post an attempt at solving the problems.

Thread Starter

#### Rio

Joined Dec 23, 2010
22
T n k ,, bro if i could i would but i can't even start ,, depended makes things complicated

#### jegues

Joined Sep 13, 2010
733
Start by taking I2 to be 0, and solve for one of the elements in the Z matrix.

Last edited:

#### t_n_k

Joined Mar 6, 2009
5,455
My approach would include firstly re-casting the circuits in their 's' domain equivalents. This is distinct from and not to be confused with the S or the scattering parameter model. I would do this because there are energy storage elements - capacitors and inductors which add to the complexity. As jeques suggests the analysis proceeds along the lines of a consideration of the representative equations for the particular parametric port model required - 'Z', 'Y', 'h' and so forth. In analyzing the circuit to deduce the four unknown parameters, one approach is to set one of the independent variables (V1, V2 or I1, I2) to zero in the relevant equation and then with a chosen fixed setting for the other independent variable, perform the analysis to eventually isolate the relevant parameter.

So in the 'Y' parametric model one has defining equations

I1=y11*V1+y12*V2
I2=y21*V1+y22*V2

To find y11 and or y21 one would analyze the circuit to determine I1 & I2 with the output shorted [making V2=0] and injecting a known input at V1 [e.g 1 volt or 1/s volts in the 's' domain].

Hence

y11=I1/V1 with V2=0
y21=I2/V1 with V2=0

To find y12 and y22 one would short the input, inject a known V2 value, analyze for I1 and I2 under those conditions and hence deduce relationships for y12 and y22.

If you are not familiar with the 's' domain or Laplace form of a circuit then I'm not sure how you would go about the analysis.

#### The Electrician

Joined Oct 9, 2007
2,834
In question 3, if you will convert the 10I2 source to an independent 10 volt source, and convert the 5V2 source to an independent 5 amp source, show how you would then go about finding the Y parameters, we can show you how to deal with those sources as dependent sources in whatever method you use.