Hello friends in this video we are going
to see a practical current source and
how it is different than that of ideal
current source so I am considering a
current source of I ampere and a very
large resistance connected parallel to
it I will name it as R SH S S stands for
shunt means parallel so this will be a
practical current source
now this practical current source I am
connecting to load register RL so that
there will be some current flowing
through the RL I named it as IL because
of which I will get voltage across RL
given by VL so again VL equals IL into
RL but because of this R Sh some current
is going to flow through this and I can
say the current flowing through the RL
is given as I minus I SH since R SH and
RL are in parallel that means fixed
voltage being applied across them so the
voltage across this R SH is same as
voltage across this RL
equal to VL so what I will do instead of
this is I sh I can write voltage divided by
resistance now suppose I want to draw VI
characteristic again the independent
variable will be VL and depends on VL I
will have IL had it given a simple ideal
current source the IL will be same as I
but because of this R SH I can say IL
will not be same as I but some value we
need to subtract from I resulting
characteristic like this so there will
be a drop in current and that drop in
current is given by VL divided by R SH
so depends on value of R SH I can have
the value of IL which is no longer same
as I but it is always less than I so IL
will always be less than I ideally
ideally I want IL same as I so in ideal
case this term should be 0 when this
term will be 0 if the denominator is
infinite so that results ideally shunt
resistance should be infinite in order
to get IL same as I but practically it
is not possible so practically
I should have IL very close to I so this
R SH should be as high as possible so I
can say practically R SH should be as
high as possible so that I will get IL
close to I so in this particular video
we have seen that the practical current
source will have the current value along
with a very large resistance connected
in parallel to it so henceforth we are
going to consider this practical current
source and we are going to convert that
into equivalent voltage source in order
to solve a problem thank you
