Electrical Engineering 2 Numericals

1. Two Loop RL Circuit 2 "Smartphysics" solution
A circuit is constructed with four resistors, one inductor, one battery and a
switch as shown. The values for the resistors are: R1 = R2 = 24 O, R3 = 111 O
and R4 = 128 O. The inductance is L = 246 mH and the battery voltage is V = 12
V. The positive terminal of the battery is indicated with a + sign.
1) The switch has been open for a long time when at time t = 0, the switch is
closed. What is I4(0), the magnitude of the current through the resistor R4 just
after the switch is closed?
A
2) What is I4(8), the magnitude of the current through the resistor R4 after the
switch has been closed for a very long time?
A
3) What is IL(8), the magnitude of the current through the inductor after the
switch has been closed for a very long time?
A
4) After the switch has been closed for a very long time, it is then opened.
What is I3(topen), the current through the resistor R3 at a time topen = 4 ms
after the switch was opened? The positive direction for the current is indicated
in the figure.
A
5) What is VL,max(closed), the magnitude of the maximum voltage across the
inductor during the time when the switch is closed?
V
6) What is VL,max(open), the magnitude of the maximum voltage across the
inductor during the time when the switch is open?
V
LCR energy "smartphysics" solution
Four resistors ( R1 = 60 Ohms, R2 = 220 Ohms, R3 = 330 Ohms, and R4 = 480 Ohms),
an ideal inductor (L = 8 mH), and a capacitor (C = 250 microF) are connected to
a battery (V = 9 V) through a switch as shown in the figure below.
The switch has been open for a long time before it is closed at t = 0. What is
Ustored, the total stored energy in the circuit elements (not including the
battery) a long time after the switch is closed? Ustored =