Question

In the circuit shown, the switch has been closed for a long time until it opens at t= 0. Find UL (t) at t = 4 usec. 2 ks2 3 ks2 t=0 5 V UL llll 4 mH + 3 V

Answer 1

solution : Assuna initially switch has been closed long time before it opens at t-o.so circuit has reached steady state. Therefore, the inductor act as ouery short circuit at steady state. Write dows ket for the circuit. 32 osv V-3 3 o-5 2 x 10 11 10) = 3.5mA. Figole circuit for tool pie ta . Initial current Now assume that the switch is opened at t=0. Time constant of R2 ak2 circuit foo tso as 404 bese L=404 Rog Figa: circuit totoo Reg - 2ks T 4X10 - 2 MS 2x 10 long-time Assuose shitch opested for a

==2.50A is doctor after ito le t = D. corrent in a 2x10 current through for tso il Its = {(68) + (Lo-ikke tiga: circuit forta = 12.5+ (3.5-2.5 et 2006 J x 10 ~5not L= 2.5+ 1 e ҮХТА for tso voltage across andoctor is alt) = L dyst) dt Kt) = 4x0xd[(25 the to ~5000 4810² x (-505 x 10 -5X1G Vit)=-ze 450 5x84x10 voltage at t= 4 usea is 14Ms) = -2 y (4us) = -zxé = -0.2706 W y (4us) = -0.27 V