Two port parameters-Z,Y,h,g,ABCD parameters
This page covers two port parameters.It includes impedance(Z parameter),admittance(Y parameter),h-parameter,g-parameter and ABCD parameter.

As shown in the figure, two port network is special case of multiport network in which each port consists of two terminals.
Z-parameters
V1 = Z11*I1 + Z12*I2
V2 = Z21*I1 + Z22*I2
Z-parameters are also called as open circuit impedance parameters.
Y-parameters
I1 = Y11*V1 + Y12*V2
I2 = Y21*V1 + Y22*V2
Y-parameters are also called short circuit admittance parameters.
h-parameters
V1 = h11*I1 + h12*V2
I2 = h21*I1 + h22*V2
Hybrid parameters are used in constructing models for transistors.
g-parameters
I1 = g11*V1 + g12*I2
V2 = g21*V1 + g22*I2
ABCD-parameters or T-parameters
V1 = A*V2 + B*I2
I1 = C*V2 + D*I2
Following table mentions condition for a network to be symmetrical and reciprocal.
Reciprocal | Symmetrical |
---|---|
Z12=Z21 | Z11=Z22 |
Y12 = Y21 | Y11 = Y22 |
|A B| |C D| is equal to one. |
A = D |
h12 = - h21 | |h11 h12| |h21 h22| is equal to one. |
g12 = -g21 | |g11 g12| |g21 g22| is equal to one. |