And calculate the voltage across the capacitor

RC circuit analysis Assignment Answers Needed

Your Question:

Before the switch is moved to position b at t = 0, the capacitor C1 is charged to 75 V through the 10 kΩ resistor. When the switch is moved to position b, the capacitor discharges through the 40 kΩ and 5 kΩ resistors in parallel. The equivalent resistance of the 40 kΩ and 5 kΩ resistors in parallel is 40 * 5 / (40 + 5) = 4 kΩ.

The voltage across the capacitor, vo(t), can be calculated using the following equation:

b) io(t)

The current through the 5 kΩ resistor, io(t), is given by the following equation:

The following SPICE simulation code can be used to simulate the circuit in Fig. P7.52 and calculate the voltage across the capacitor, vo(t), and the current through the 5 kΩ resistor, io(t):

* Circuit in Fig. P7.52

R3 3 0 5k

V2 4 0 100 V

* Print results

.print DC V(2) I(R3)

2.00µs 71.41V 2.86mA

...

[Plot of vo(t)]

The current through the 5 kΩ resistor, io(t), is plotted in the following graph: