i wanna bjt we som time assume collecter current equal to the emittr n why some time not.......

 

In terms of Ic you have this formula: Ic = Ib * B
where B = beta and Ib = base current.
In terms of Ie you have this formula: Ie = Ib + Ic
where Ic = collector current and Ie = emitter current
If the 1st equation is substituted to the 2nd equation in terms of Ic you will have this equation Ie = (Ic/B) + Ic

Extracting Ic you will have this equation Ie = Ic((1/B) + 1)

Typically B = 100 so ((1/B) + 1) is approximately equal to 1

With this Ie is also approximately equal to Ic.

Hope this helps.....

 

Hi all,
I just wanted to say to Engr, excellent analysis, your spot-on.

Regards,
Kamran Kazem

 

thanks alot.......................