1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Basic npn bjt problem

  1. Nov 13, 2017 #1
    1. The problem statement, all variables and given/known data
    bjt q5.png

    2. Relevant equations
    KVL

    3. The attempt at a solution
    Using KVL around BE loop
    0-0.6-i_e*(30*10^3)-15=0
    i_e=-0.52mA
    However, I stuck when I tried to find i_c and use KVL around CE loop/ CB loop
    For CE loop:
    10-i_c*(15*10^3)-Vce-i_e*(30*10^3)-15=0
    For CB loop:
    10-i_c*(15*10^3)-Vcb=0
    I got confused about how to relate Vce and Vcb. (here I guess it must be some kind of relationship that looks like Vbc-Vac=Vba)
    Also, it seems like it is operating in cutoff mode (both Vc and Ve>Vb), however, there is current flowing around the loop. So what is the mode that the transistor is actually operating in?
    Thank you!:confused:
     
  2. jcsd
  3. Nov 13, 2017 #2

    CWatters

    User Avatar
    Science Advisor
    Homework Helper

    Circuit looks odd to me. Like common base configuration but the polarity of the emitter bias voltage is wrong ( should be -15v). Think the transistor is either off or they made a mistake?

    Otherwise I would suggest you assume Ic=Ie.
     
  4. Nov 13, 2017 #3

    NascentOxygen

    User Avatar

    Staff: Mentor

    Yes, try reversing the polarity of the 15v supply.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Basic npn bjt problem
  1. BJT problem (Replies: 2)

  2. BJT problem (Replies: 9)

Loading...