Question

i. Prove that the voltage gain of following configuration is unity (1) if: Vcc = 16 V R3 = 330 ko RE= 2.2 ko ro= 50 ko B= 80 Vcc RB C2 HE EO RE Z Based on the above configuration, find the value of voltage and current gain and compare the voltage gain with question (1) if: Vcc = 12 V R3 = 390 kO RE= 5.6 k 2 7 = 40 k2 B= 120

Answer 1

Vee 0 RB B Vo RE 2 Given, B = 80 Vecalov RB = 33oun 8o = sokn Rs = 2.2 len 1 undes ac Capacitor :- Short car cesit Ground analysis Vee The modefied figure RBE Common Collector figi Config Voltage gain gain (Au- Vo Ave (1+8) Ri da + (1+ BRL Ri= Relloo 2.250 - 2.39 kn 2.2 *

Axe (1480 (2.2) ST+ (1+80) (2.2) 25 nv We know that i = Vs' & Dé analysis {A c Signal Deanalepis rust aircuit Capacitor open 16V ac RB B + 0.74 a (8 do RE (2.2km) 2 eti) kve: 16 = 93 (350) + 0.7 at + Cet f) în (22) 16 = 2B (330+ 1) (2.2)) +0.7 IB= 0.0301MA 28 mv 830.39 kn TT 2 ? 0.030lm 6,83 kn Au (81) (22) - 0.9953 0.83 + (81) (2-2) ²1 inity

Ac anddays: le E 22 Vi + RE J Veca 12v ro= toka RB 23gokh RE= 5.6ks }=120 input resistance of Bys Ry z dn & G&B)P, Rell to =) (5.91140 - 4.aks = Vr TB De analyst from previsu evious problema 964 P & 12= IB (RB) + 0.7 & PB + 2) R5 12= 2B (396) at 0.7 11 109&rs (56) 12 - 8 (390 + (2156)) 10.7 AB=0.0105 mA 28mv sa va 0.0/05mA 238 0.92 This (6) 2.38kn

-le = (1+B) ib Great going ago in a = 121 is ir Current goin ay amplyien e 2 I. fie I; o loc.ie ie le - ( 21 y ما وے 2.384 we have, Ri = n + ( 14 ) ķ (et 180) (4.9) = 595.8 kn ib I; Ri RB from Current divider rule : RB is RB tri 390 3904595.8 0.3988

3 (0) (-120)(0.3959) : Current gain 47.89 Current goin V. -> (1+B) Ru (1+B) a (14120 4.9 2.38 + (at 120) Ay vol goin 0.996 goins Theme significant change occured 2 tine is no in wl e goin