# q04 - Q 2 with a voltage source labeled v tb 2 in series...

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ECE3050Ana logE lectron icsQu iz4 September 16, 2009 Professor Leach Last Name: First Name: Instructions. Print your name in the spaces above. Place a box around any answer. Honor Code Statement: I have neither given nor received help on this quiz. Initials Given equations: i 0 c = g m v π = αi 0 e = βi b , g m = I C /V T , r π = V T /I B ,and r e = V T /I E ,and I C = αI E = βI B . 1 of 2. The signal circuit of a two-stage BJT ampli f er is shown. It is given that I E 1 =1 . 25mA , I E 2 =2 . 5mA , α =0 . 99 , β =99 , r x =0 , r 0 = , V T =0 . 025V , R S =50 , R C =2 . 4k ,and R E = 300 . (a) In terms of CE, CB, and CC, how would you describe this circuit? (b) Solve for r in . (c) Denote the Thévenin equivalent circuit seen looking out of the base of Q 2 by v tb 2 and R tb 2 .W i t h Q 2 erased, solve for v tb 2 /v s and R tb 2 . Use any one of the small-signal circuits covered in class. Let v s 1 The value off v o is the voltage gain. r e1 V T I E1 r e1 20 = r e2 V T I E2 r e2 10 = r' e1 r e1 i' e1 v s R S r' e1 i' e1 0.014 = v tb2 α i' e1 . R C . v tb2 33.943 = r in

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2 of 2. Replace the circuit seen looking out of the base of
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Unformatted text preview: Q 2 with a voltage source labeled v tb 2 in series with the resistance R tb 2 found in problem 1. (a) Solve for v o /v tb 2 and r out . Use any one of the small-signal circuits covered in class. Note — you don’t need a number for v tb 2 , but you do need a number for R tb 2 . Even if you don’t know how to work problem 1, you should be able to tell the value of R tb 2 by inspection of the circuit diagram given. (b) Put the answers for problems 1 and 2 together to solve for v o /v s . R tb2 R C r' e2 R tb2 1 β r e2 r' e2 34 = i' e2 v tb2 r' e2 R E i' e2 0.102 = v o1 i' e2 R E . v o1 30.488 = Solution 1 v o2 v tb2 R E r' e2 R E . v o2 30.488 = Solution 2 r out R p2 R E r' e2 , r out 30.539 = 2...
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## This note was uploaded on 05/26/2011 for the course ECE 3050 taught by Professor Hollis during the Summer '08 term at Georgia Tech.

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q04 - Q 2 with a voltage source labeled v tb 2 in series...

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