Please help with the following problem.
The DC load line and Q point of the circuit are shown next to the circuit. For the transistor, Beta=120. Find Re, R1, and R2 such that the circuit is bias stable.
Is it valid for me to do a KVL around the C-E loop using ic=4.8ma and vce=6v (ie=ic (b+1/b)) to find RE? And then get Rth=.1(1+beta)*Re?
Can I just arbitrarily choose an r1 and use rth to get r2? How do find the correct values of r1 and r2, and is my approach correct to this point?
A diagram to make things clearer is attached.
Thank you.© BrainMass Inc. brainmass.com December 24, 2021, 4:54 pm ad1c9bdddf
I think your approach is correct. I'll go through the KVL just to make sure I am thinking the same thing you are.
18V - IC*(2k) - VCE - IE*(RE) = 0
18V - 4.8mA*(2k) - 6V - 4.8*RE*(B+1)/B = 0
18V - 4.8mA*(2k) - 6V - 4.8*RE*(1.008) = 0
RE = 496 ohms
I would do this next:
Find VB to satisfy this bias condition. First find VE:
The solution works with the material suggested by the question to reach an answer in clear, succinct terms.