Hello friends in this video we are going
to see how to use star delta conversion
in order to solve a problem of
equivalent resistance between two points
given let's illustrate the concept of
star delta conversion so that it will
facilities and parallel connections in
order to reduce a circuit into a single
resistance connected between points a
and B so let us take a numerical so here
I have taken a problem having so many
resistors connected let us give the
value to them objective is to find out
equivalent resistance between points a
and B so here if I see the network
properly I will not find out any series
or parallel connections given directly
but if I simplify the network by using
any star to Delta or Delta 2 star
conversion then I may get some more
other series and parallel connections
which will give you a combination
ultimately into single resistance
between a and B so my job is to I need
to convert one of the star or Delta into
corresponding counterpart so whenever we
are converting star to Delta or Delta to
star one thing we have to keep in mind
and that thing is that whenever we are
converting we have to make sure that
points of interest will not get lost
meaning I should not take any star or
Delta Connection which will make this a
and B point vanish so considering this
fact in mind I will consider this Delta
which I am going to convert
into equivalent star so remember star
has four points Delta has three so
already three points are there one two
three star will introduce one more point
so I will consider this point and then
the remaining three points will get
connected to this fourth point with
registers so first we will identify
which star or Delta we are going to
convert into its corresponding
counterpart then we will redraw the
circuit solve a redraw the circuit first
so the circuit will look like this and
now we will give the value to these
registers so already we are not touching
this twenty Oh same way for this 20 oh
now we have to find out values for this
star connected registers so between 1001
1002
we are converting Delta to star so
whenever we are connected in Delta to
star the formula is we need to multiply
the registers divided by addition of all
the three registers connected in Delta
so after solving this I will get an
answer now between ten to forty five
multiplication of two registers divided
by addition of three so already we have
added this three it's comes around to be
65 and I will get answer as 6.9 two
three one similarly the third register
is also between 45 and ten since this is
same as this second register I can say
the value is six point nine two three
one oh so this register is between ten
and ten answer is 1 point 5 3 8 5 this
register between 45 10 6.92 3 1 this is
between 45 10 once again it is six point
nine two three one so after doing this
see the change in the circuit I will get
registers now in series twenty and six
point nine two three one will give me
answer twenty six point nine two three
one same way over here twenty six point
nine two three one let us redraw the
circuit the circuit will look like this
1.53 at five will remain as it is
because we have not touched that this
will reduce into a one resistors twenty
six point nine two three one same way
over here twenty six point nine two
three one and then these two resistors
are in parallel so the equivalent is I
can get direct answer thirteen point
four six one five because these are the
two registers are of the same value and
are in parallel so I can say the
equivalent is just divided by two so I
will get thirteen point four six one
five and then this resistance will come
in series with one point five three
eight five so that I will get equivalent
resistance between points a and B one
point five three eight five plus
thirteen point four six one five if I
solve this I will get final answer that
is equivalent resistance between points
a and B as fifteen oh thank you
