Question

3. (a) Find the h-parameters for the 2-port network shown in Figure 3. (b) Obtain the impedance Z111(s) between the terminal 1-1' when Z1 Z2 = Z3 = 1 and Z4 = 1 and a resistor R= 1N is connected between the terminals 2-2. I I, 1 2 + + V, ZA v 12 "I 2 23 Figure 3.

Answer 1

ho h- parameter for any two port network is defined I 72 [h V2 Vi= hil Ist hir V2 Iza hil, at haz Vz Nede 3D Node Nsde o 11 +V+ OA V2 (3) Jon to 23 42 Z1 DA 12 VOI Non 프 ( ON Izz IZ Node ① for Node On Virtual ground Concept ideal opomp, is applicable je V+ EV- current into the op-amp ie 17 -150A ang terminals are Ze20 from the above circuit for op-ump 6 Vt au- (op amp @ I V-( opomp)

V + Va for O modo V + for 6-от Р V+= V1 = V ar Vi - V2 apply kck ay node Is = Izit OA 121]-in Vola V - Vog Z, Eym 'I. FA Vi = Vol = I ZI Voi = Helge at nude 2 Kch at nolle apply Izg= EZI to Voj-V+ vt_voz - 22 Here vozo Voltage Z3 at noole 5 VIV+ = 42

Vor- Ve Ze Nervor Z3 VOL 22 + Voz Vz Zo + 22 23 Vol + V2 22 V [ * +3] 23 folin apply Ken at node Iztoa I 23 Iz V2 - Voz Z3 V2 Iq 23 voz Úw) Voz - U2 - Iz 23 put Voi = V, -I, ZI & No2= Ve- I2 Zz in 1 from Eqm ༼༡༽ ged V,-1,21 + N2- Iz ?3 Z 3 - V2 72 [***] 175 17-17 vo لها t 22

Iz Z2 +Ia Vz Zz 22 from Eqn Ni=v2 Izi 22 + Ila - Kr = 0 Iizi + 12 "Z2 I zi t I 2 Zq=o TIZI 1, 22 Iz 21 Il Z2 6oo) so We gef Vi = 12 I, 21 Z 2 I Vio hol Is this a OTI + 1 V2 hizo h12=1 I half the 282 -ZI, +OV2 hei= 21 Za hezzo

b-parameter Thai hiz har har IN] I 2 2) h. parameter b > iti we conneet ..R=102. resistor а сеY03-30 then from the urant V2 IqR, = -1 2 x 1 (by ohm's lin) I2 N2 I 2 ZIL 2. &R -1 I We have determined fromegn 22 V-Ve fomigo Liv> I, = -2X I 2,1115) V IT V1 Z2 지 x Iz Fresh V₂ = - Iz Vic-12 & 4 = V2

by putting Vi - Iz Zils) Vi t = IL XIA 22 Iz 2 * 32 Iz Zorils) ZI - 22 Here giren Z,= Zqca Z3=1 24 = % Zi'ls) i I - 1 u 1 Zli'ls) 1