Question

Electronics I

Electronics I

Electronics I

Electronics I

Electronics I

Please if you are not sure %100 of the answer do not solve it, there might be solution on chegg already but not completly right. thank you

for each transistor in the circuit in figure the parameters ave B-125 , VeEcon) = 0.7, V1=2661 and yoz do Both transistors are biased in forward active mode such that Icon=0.364 mA and I co2=4.82 mA 1st) Draw complete small-siqnal equivalent circuit 2nd) Find the input and output impedances of multistage amplifier V + +5v Par con 3 Blok R2Z6K Z REI= {21.5kr 90.2ke VE-5v

Answer 1

Initially ac equivalent quantities are to be found. Later ac equivalent circuit is drawn by replacing transistors with their smalll signal models.
Given Br 125 V BECOND = 0.7, V = 26 mV, rocco IcQ = 0.36 4mA. Icon = 4.82 mA. Na, Imi gmi = Ica Ime ² Ical T VT 4.82mA 26mv 0.36uMA 26mV 0.014 v = 0.1854 v ir Sal = 125 0.014 . SA2 = 125 0.1854 = 8.929 kr = 0.674 kr. AC model of transistor Q, a 11 B b Voer i Bibi VA = 8.9296.2 = 125. ro = 0o (open ckt) ß E AC model of a :- transistor 162 Pa2 = 0.674ka Biba Vber ß = 125. ro=00 (open ckt)

For the short small signal equivalent circuit, all dc sources and capacitors are circuited. {1.5K & lok. & Elor 20.2K. 7 who 5k.

Small signal equivalent ckt :- G B 162 Bibco To.Gluk 125i62 © 26 ber 18.929k. E2. 1.5k @ Input impedance 29 = (6k||+0k) || Ry KVL - Voci - 8.929kib, - 0.2k (ibiti 25 ibi) = 0 Vbei - 8.929K 16 - 25.2kib, = 0 Voei = 34.129 kibe bel - Ri = 34.12962 ibi

. Input impedance Ri - (6K1110k) || 34.1296... - 5.526 | 34./292 Ra = 4.76621 calculated by short sources and applying output impedance is circuiting the input the test voltage Vr.

By ibi B 162 Jo Oo sk. Ver $6k|| tok ve 1 0,1256 I Lovor Love LOE 30.2kn 1.5k slok a + Output resistance Ro Since Vs = 0 = Vbel = 0 = 6, o ic, =O & Vc, = 0. Vc = 0 = Vbez = 0 & 1b2 = 0 => "C2 = 0 KCL VI + VI - IT = o. vo (1 set ox) = It V = -56 || 10k. (5K lok 12 Ro = 1.30ukr