Question

The figure below shows a simplified model of a cardiac defibrilator, a device used to resuscitate patients in ventricular Abrilation +L TC Riorso When the switch is toggled to the left, the capacitor charges through the resistor R. When the switch is toggled to the right, the capacitor discharges current through the patient's torso, modeled as the resistor R a llowing the heart's normal rhythm to be reestablished. (a) If the capacitor is initially uncharged with C-7.75 F and 1260 V, find the value of R (in ohms) required to charge the capacitor to a voltage of 765 Vin 1.30 s. (b) If the capacitor is the discharged across the patient's torso with Rose 1230 , calculate the voltage (in V) across the capacitor after 5.50 ms.

Answer 1

Use the voltage equation across capacitor for charging circuit to find the value of resistance as shown below. Use the capacitor voltage and equation for discharging circuit to find the voltage across the capacitor after given time as shown below

(Vo = max. voltage Vc (t) = Vo(1-0-717) => Vc (135) = E(2-2-1310) => 765V = 12600 (1-0-13/) => I = 1.39 s 3 RC = 1.395 =) R(775UF) = 1.39s = R= 1.795x10512 across capacitor = E V(t) = Voltage across - capacitor at time t ī= time constant Here I = R torso C = (12303) 7.7546) = 9.53 ms for discharging V = Voe-t/ V-765V = (2651) e-ssms/assas = 429.62 v