Lecture 10 : Transmisssion Line Calculations Using Smith Chart
(E)
Location of Voltage Maximum or Minimum
At the location of voltage maximum the impedance is maximum (
), and at the location of voltage minimum
the impedance is minimum (
). Hence point T indicates the location of voltage maximum and point S indicates
the location of voltage minimum in figure below
To find distance of these points from the load, measure the angle
between the load point P and point T
and between point P and point S respectively in the clockwise direction from P to T.The angle PMT in the
clockwise direction when divided
by
gives the distance of the voltage maximum from the load,
. Similarly
one can obtain distance
of voltage minimum,
by measuring angle PMS in clockwise direction.
Alternatively one can make use of the fact that the voltage maximum and minimum are seperated by a
distance of . That is
), and at the location of voltage minimum
the impedance is minimum (
). Hence point T indicates the location of voltage maximum and point S indicates
the location of voltage minimum in figure below 
gives the distance of the voltage maximum from the load,
. Similarly
one can obtain distance
of voltage minimum,
by measuring angle PMS in clockwise direction.
. That is
