Question

The input voltage waveform (Vin) t in is shown below along with the circuit. The voltage-controlled switch S1 closes when the output voltage Vc (t) goes positive at t=0 and opens when Vc (t) goes negative at t=5 µs. Assume that Vin(t) in has been at 10 V for t<0 for a very long time..

3. (15 marks) The input voltage waveform Vin(t) is shown below along with the circuit. The voltage- controlled switch S, closes when the output voltage V.(t) goes positive at t=0 and opens when VO) goes negative at 1-5 yes. Assume that V (t) has been at -10 V for t <0 for a very long time. Determine the voltage Vc(t) at a) (3 marks) A:t<0; b) (7 marks) B:05t<5us; c) (5 marks) C:t> 5us. 15 pf Ant 5 tus) - -10V A B

Answer 1

Given mm rsa Vin TISPP Vect) {20kn TISPP 2011 IT - tlus) - -lov (a) ov " switch is open attco at t -o- - FISpare capacitor is charged hence it acts as open ciruit. so, VECO) = -lov from the cirwit, the capacitor Noltage Volg =-100 I jtco at t=0 the switch is closed. the comit will be for ostasuses (b) zov (A) 20k +10ook zokns V ) 400 1020 himin 1518 t. val= 200 x 20 D e vecan) = 4- 20 veety = Velad) + [vecoy - Vecms] é tle Vect = 200+ [-10-2017 ēte; ostą susee Vecm) = 20 - 530 e-tie; o5 ts smeee time constant (0) = Req c = (306x 0 J X 15X17'2 2 = (2.00.90 "jxis xlo12 z=is usee 20k + lodo

ve the long (2 - 53 € (17)32367; 0<t<space y g = Lig (2-s3 espigot); os es stive? (C) Im -ww @ for to stesee, the switch is again opened. TEASERATI U velsp) = 10 [2-53 e Pillotso) VCSM) = (2-53 e51/3 ] PC(SMC) = (2-53 817] 1 Ve(541) 20.3921 Volt and, V.120) = -10V so, rect) = veco) + [viestu) - vel]e 72 ;+?sused Veet = -10 + [0.3924 +10 Jette; +75 pesce Neem 2 -10 +10.3924 ette; to stesee time constant z = Reqco tovox 103x1541012 2= 15usee Veet = -10 +10.3924 é tsxiób ; t Spesee Vect) = -10710.3924 element; t7 sused