Question

Problem #2: The switch has been open for a long time before closing at t = 0. Find Vct) fort > 0. W 812 3202 33022 Veſt)+ 0.1 MF 200 V

Answer 1

NA ttco ೩೦AL sou ve (t) = 0.1uf It 62001 Switch has been open » Circuit is in steady before switen is closed Capacitor acts as for long time state just (t=0") open circut - AAA dol V. ) A 1. uco-) = ov ( due to no ource) Capacitor doesn't allow sudden change in vo Hage >> Vcot) = “ COJ- ov Now a long time ( t o ) after closing the switch, circuit reaches Steady State » open Capacitor ( fo) 6+ { or 2or 2oov

Due to open flows in or Nodal analysis circuit, no current hode voltage avecool. = Y + Vc-200 =0 30 → 34 + 2CVE-200) =0 - Sve - 400 = 0 > Ve = 400 = 80V. i. vca = 80v. To find time constant, a > Y = Rearic (20) find Rear for £20) from - short 2004 source. Capacitor. 301? e Rea 200} .. Rey - (20/1 30) +8 Qo) (30) + 8 20+30 12 + 8 = = 202 .:. c = (20) (0.1 m) =am sec

Vect) = vc Coo) + [vecot) - vecos e te;too = 80 + (0-80] e-7/24 = 80 - 80 - Sooooot => VECH) = 80(1-e - 50000t)),