Question

RC Circuits Case 1: Case 2: w V W v = R V = WM Consider the two circuits. Initiall the switch is open, and then the switch is closed (completing the circuit). a) For Case 1: What is the current through the battery immediately after the switch is closed? Describe what happens to the current as a function of time, going to times much longer than any RC time constant. Why? b) For Case 1: What is the current through the battery immediately after the switch is closed? Describe what happens to the current as a function of time, going to times much longer than any RC time constant. Why? c) After a long time when all transients are gone, and the capacitors are fully charged, the switch is now opened. Describe what happens to currents and voltages in both circuits as a function of time after the switch is opened.

Answer 1

E @ For Case - Through Capacitor current does not flow immediately after switch is closed. Current passes through two Resistance, as shown z i i Current through battery in Maximum charge on capacitor, 9= clie), After a much longer time capacitor is completely charged and becomes a short circuited tence No current through parallel resistance. then Current I= ² case 2 Initially (t=o) Capacitor is open circuit Hence current through only one resistance for case 2 Initially it for case o After long time, capacitor becomes completely charge Hence short circuited i.e., iz r Capacitor t switch is open the the ischanges through parallel resistance R, tence time constant T=CR and charge a= ao e tina I (t) = 9o. etler) Potential Vet = re q =CR . tice VC)= ve E/CR) >> I(t) = cries $1(f) - v ettler) are in series with a time cantant T = C(2R) for Case 2: Two Resistance after circuit is open, Hence - (t/2cR) i I (+) = 2 r e V(f) are - (t/20R)