Electrical Circuits I
Dr. Mohammad Monirujjaman Khan
Assistant Professor
Electrical and Computer Engineering
•The single path now including
the effects of two mesh currents
is referred to as the path of a
supermesh current.
•In the above analysis, it may appear that when the current source was
removed, I1 =I2.
•However, the supermesh approach requires that we stick with the
original definition of each mesh current and not alter those definitions
when current sources are removed.
•A technique for writing the mesh equations more rapidly and usually
with fewer errors.
•Column 1 is composed of a loop current
times the sum of the resistors through
which that loop current passes
•Column 2 is the product of the
resistors common to another loop
current times that other loop current.
•Note that in each equation, this column is subtracted from column 1.
•Column 3 is the algebraic sum of the voltage sources through which the
loop current of interest passes.
•The above statements can be extended to develop the following format approach to mesh
analysis.
•The format approach can be applied only to networks in which
all current sources have been converted to their equivalent voltage
source.
Give it a try
•One source of voltage to point out that mesh analysis can be used to
advantage in other than multisource networks.
•Circuit configurations are often encountered in which the resistors do
not appear to be in series or parallel.
•Under these conditions, it may be necessary to convert the circuit
from one form to another to solve for any unknown quantities if mesh
or nodal analysis is not applied
•Two circuit configurations that often account for these difficulties are
the wye (Y) and delta (Δ) configurations
•They are also referred to as
the pi is actually an inverted delta.
•It is our purpose (referring to Fig. 77) to
find some expression for R1, R2, and R3 in
terms of RA, RB, and RC, and vice versa
•That will ensure that the resistance
between any two terminals of the Y
configuration will be the same with the Δ
configuration inserted in place of the Y
configuration (and vice versa)
•If the two circuits are to be equivalent, the total resistance between any
two terminals must be the same.
•Consider terminals a-c in the
Thank you