Hi,
I want to calculate current through circuit shown in attached file.

Actually i want the formula or the way/method to calculate it.
The parallel combination confusing me.

V5,V6 are diode forward voltage drops.

The voltage drops,resistor values used only for easy calculation.

 

Show as your work. We need to know where you made a mistake. So we can help you better.
Also read this example
http://forum.allaboutcircuits.com/showpost.php?p=537804&postcount=8

 

I would define a current I1 and I2 going thru each parallel branch, and note by inspection that I1 = I2.

Then a simple loop equation will tell everything:

{source V} = {drop 1} + {drop 2} + ... + {drop n}

10V = (I1 * 2ohms - 1V) + (2*I1 * 1ohm)

 

Below is the simplified circuit in which am suppose to calculate total current.

If we consider diode Vf as 1V and transistor Vce = 0.7V, Vbe = 0.5V for calculation,and the transistor is in ON condition,

how to calculate total current flowing through three loops i.e. through R1,R2,D1,U1,D2,R4 and through R5,R6,U1,D2,R4 and R5,R3,D2,R4 loops.