Question

(4) Determine and draw the Thevenin equivalent circuit with respect to terminals a and b. 20ix i 452 42

Answer 1

Ini 3 a Th KCL at node u 4 m[ * ++++] - Mi[ 142+1) - 44,- V2 = 9 - KCL at node V. » V2 V1 + 3 x = 0 4 Since, V = -Us V2 -v1 + 3(-V4) = 0 -30 =0 © V2 = 13v1 - Uning 0 and , Vi=t, 12 = -13 = 1 =-11, 12 = -13v kvL at loop ② = a + 20 in-Uth=0 th= Vat zoin Refer to Figl, in- 9-11 - 9-(-1) = 10 = 5/2 A

th=– 13 + 20 x 5 37 V I th= 37 Now Determine Rith: short circuit arb Find short erruit current Isc, and Uth Rth Isc & Isc 3va U = 0 ked at node u vina + Vive 45,- V2 = 9 - 3 KcL at node 12, -~ + 3 Vzx + Ise = 0 Sina Ne=-v, V-VI + 3(-u) + Iso = 0 — Also, the voltage V2 =- 20ix - 6 uring 6 and V2 = -20[q-1 12 = – 45 + 54 54-42 = 45 ② & 6 V = 36v, 12 = 1350 solving

substitute above valun in 135-36 +3(-36) + Isc = 0 Isc = + 83.25 A Isc= 83.25 A Rith = Th = 3 - 83.25 = 0. = 0.444 n. Isc Rih= 0.444 ha 37 (t Thevenin's Equivalent