I have Biased the transistor Q1 in active region as shown in the following diagram. I have Sensor which outputs 1-10ma and needs to be connected across parallel as per the following diagram. the transistor is biased in such way that for 1-3mA of sensor output it remains in active region and for 3-10 mA it switches to Saturation region. Now how do i calculate the current I2, I3 and I4 theoretically ?
Current without the Connection of external sensor I4= 864uA , I2= 72.208uA
Current With external Current sensor for 10 mA source : 10/11.96= 0.8361uA
So I2'= (72.208 + 0.863 ) uA and I4'= [864 + (10-08361) ] uA
This calculation is not precise and slightly vary from the simulated results . Kindly Suggest me theoretical Approach to solve this for mentioned Currents. will there by any current flowing inside 15 V source from the external sensor ?