Question

For the cascade amplifier of Figure Q1(a), determine the (1) transconductance factor, gm. a.c. diode resistance., re. (iii) ac equivalent circuit (iv) input impedance, Z (v) output impedance, Z. (vi) voltage gain, Avi (vii) voltage gain, Av2. (viii) total cascade voltage gain, Avr. Given gm = 21 pss lvpl

Answer 1

* ño For the cascade Amplifier, given the picture ) Trans conductance factor, a Ids gm augs For FET, gmi Vgg lvpl Vp biven, Idss - 10 MA up -40 Vasa .. .. 2 Ides (Given -1050 gmi fisu 740 1-41 20 ..0.375 gmi 4 gmi 3.125 ms

we know, 9m₂ = Ic Vy lite (hte dve By the Dc equilaent circuit of BJT Re I LEV Flok Rith AUL VT IB B2160 + RE & Ik Vih 15% 2.2%, 33 e):36V (22+2:2714 24:2 Rith = 21261/22k Rith 2k.n ** 18 Vin-VBE Rin+ (1+B)RE 1.36V 0.7 2K+(101) IK al 0.66 103K IB 6.4 MA le=BIB ) le= (100) (6.4) Ic 6.4MA

7 gm2 Ic 6.4nha 25mA 560 т. 20.256 gm2 E 2560ms (ii) Ac diode resistance, re Vy .IE 25mv (1+B2.IB 25mv (101) 6.4 let) re = 38.60 liz Ac equivalent circuit B Voi 10 + I c.2mm) Base 3:3 Rinkvbe & E at ERG @gma Vq zo TY Zin

- 1.2M:N output Av2 = -gm Re (ii) Input impedance, Zin Zins RG- (iv) impedance, Zo Zo= roll Re 40k 11 LOK Look Zo= 8kN Ni) : Voltage gam, Avi Ava - gm Ro = -(2.125s (2 (Nii) Voltage gam, Arz -(2568) (2016) 10:31 V/ -25600

Vill). Total caseade voltage g gain, AV. (-10.31)(-2560) AUX AV2 AVG : 26.3K. V/