Two Port Networks | Sahithyan's Notes

An electrical network with two separate ports for input and output.

A pair of terminals through which current may enter or leave a network.

Parameters

Also known as open-circuit impedance parameters. Denoted by $[z]$ . Measures impedance of the network.

\begin{bmatrix} V_1 \\ V_2 \end{bmatrix} = \begin{bmatrix} z_{11} & z_{12} \\ z_{21} & z_{22} \\ \end{bmatrix} \begin{bmatrix} I_1 \\ I_2 \end{bmatrix} = [z] \begin{bmatrix} I_1 \\ I_2 \end{bmatrix}

The parameters are found by setting $I_1$ and $I_2$ to $0$ in turn.

Also known as short-circuit admittance parameters. Denoted by $[y]$ . Measures admittance of the network.

\begin{bmatrix} I_1 \\ I_2 \end{bmatrix} = \begin{bmatrix} y_{11} & y_{12} \\ y_{21} & y_{22} \\ \end{bmatrix} \begin{bmatrix} V_1 \\ V_2 \end{bmatrix} = [y] \begin{bmatrix} V_1 \\ V_2 \end{bmatrix}

The parameters are found by setting $V_1$ and $V_2$ to $0$ in turn. Same as the inverse of the $[z]$ parameters.

Also known as ABCD parameters. Denoted by $T$ . Measures gain and transfer impedance and transfer admittance.

Transmission parameters

\begin{bmatrix} V_1 \\ I_1 \end{bmatrix} = \begin{bmatrix} A & B \\ C & D \\ \end{bmatrix} \begin{bmatrix} V_2 \\ -I_2 \end{bmatrix}

Here:

The parameters are found by setting $I_2$ and $V_2$ to $0$ in turn.

A network is said to be reciprocal if $AD-BC=1$ .

\begin{bmatrix} V_1 \\ I_2 \end{bmatrix} = \begin{bmatrix} h_{11} & h_{12} \\ h_{21} & h_{22} \\ \end{bmatrix} \begin{bmatrix} I_1 \\ V_2 \end{bmatrix} = [h] \begin{bmatrix} I_1 \\ V_2 \end{bmatrix}