Y-PARAMETER of Two Port Network

Hello friends, in this article we will study about Y Parameter of two port network.

Y-Parameter is also called "Short Circuit Parameter" and "Admittance Parameter".


In Y-Parameter, the input and output currents are function of input and output Voltages.
( I1 , I2 )      =        f ( V1 , V2 )

It can also be written as:
[I] = [Y]   [V]
 where [Y] represents Admittance Matrix.

In matrix form,
[I1] =    [Y11  Y12]   [V1]
[I2] =    [Y21  Y22]   [V2]

Writing it in equation,
I1 = Y11* V1 + Y12* V2 .........eq1
I2 = Y21* V1 + Y22* V2 .........eq2

Related pages.                                 
  • Z-PARAMETER OF TWO PORT NETWORK

CASE-1 SHORT CIRCUITING THE OUTPUT PORT.

If the Output port of the two port network is  short circuited then output voltage is zero, i.e. V2 = 0.

Now, equation 1 and 2 will be reduced to :
I1 = Y11* V1
I2 = Y21* V1

So, Y11 = I1 /V1    ( keeping V2 = 0 )
      Y21 = I2/ V1    ( keeping V2 = 0 )

CASE-2 SHORT CIRCUITING THE INPUT PORT.

If the Input port of the two port network is short circuited then the input voltage is zero, i.e. V1 = 0.

Now, equation 1 and 2 will be reduced to :
I1 = Y12* V2
I2 = Y22* V2

So, Y12 = I1/ V2    ( keeping V1= 0 )
      Y22 = I2/ V2  ( keeping V1 = 0 )

Y11 is called input driving point Admittance.
Y12 is called forward transfer Admittance.
Y21 is called reverse transfer Admittance
Y22 is called output driving point Admittance.

For a network to be symmetrical , Y11 = Y22
For a network to be reciprocal, Y12 = Y21

EQUIVALENT CIRCUIT OF Y-PARAMETER

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