Question

Problem 2: In the circuit on Figure P2, BJT NPN Q1 and Q2 emulate a Darlington Pair (DP). It should be noted that Q1 and Q2 are such that their current gains are B1 B2 = B = 99. Moreover, capacitors C1 and C2 can be assumed to be very large. Note: The DC analysis of the DP circuit below can be done in a similar fashion as what you do when only dealing with one transistor. Express the current going through resistor R4 in terms of the base current of Q1. Use the Thevenin equivalence technique to combine the network of Vi, Rj, and R2 into an equivalent resistor (Rpp) and an equivalent voltage (VBB). Use KVL (on the loop going from the base of Q1 to the emitter of Q2) to determine the base current of Q1. The base current of Q1 is the same current that goes through the equivalent resistor (RBB). Once you find the base current of Q1, all the other currents can be found. V1 15.0V R1 R3 32.5kn 68kn C2 Vout C1 Q1 Q2 Vsig R2 R4 1ko 28.3kn

Answer 1

SV DAnalyss P32.Sk RBB v, (23.3k 6sk+ 28.3k Valts EE kvL h-RBB,VBG +B) IB (+p) +Bs 5ubstitut Korts - 3x10 -A -A -3χ1Ο 3 A S A 2.9x10 -A- 9x 26 x1 E 63.3 Ł - 2.9x 5 99x26x10 83.3 2.9x13

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