**open circuit line:-**

In order to observe the properties of an open circuited Transmission Line, chose a Transmission line of length l and is open circuited at the load end.

from the figure

– Source voltage (at sending end (or) source end).

– Source current (at sending end (or) source end).

– Load voltage (at receiving end (or) Load end).

– Load current (at receiving end (or) Load end).

at Load end , maximum voltage and .

We knew that the input impedance of a Transmission line is given by .

after substituting the conditions of a open circuit conditions that is

.

.

if the Transmission line is a loss-less line then and .

.

. since .

**alternative method:- **

The alternative way to derive the input impedance is by using voltage and current equations of a basic Transmission line

.

.

at , and then the equations changes to

.

.

by substituting in equation(2) and also choosing the line as loss-less line

.

. since and .

.

.

**short circuit line:-**

In order to observe the properties of an short circuited Transmission Line, chose a Transmission line of length l and is short circuited at the load end.

from the figure

– Source voltage (at sending end (or) source end).

– Source current (at sending end (or) source end).

– Load voltage (at receiving end (or) Load end).

– Load current (at receiving end (or) Load end).

at Load end , maximum current and .

We knew that the input impedance of a Transmission line is given by .

after substituting the conditions of a short circuit conditions that is

.

if the Transmission line is a loss-less line then and .

.

. since .

**alternative method:- **

The alternative way to derive the input impedance is by using voltage and current equations of a basic Transmission line

.

.

at , and then the equations changes to

.

.

by substituting in equation(1) and also choosing the line as loss-less line

.

. since and .

.

.