For the circuit shown below the voltage on all of the capaci

For the circuit shown below the voltage on all of the capacitors is 0 when t = 0. R1 and R2 are required for PSpice analysis because PSpice requires a dc path to ground, but may be neglected in hand analysis except when specifically asked for. Using scientific notation write the numeric value of R1. What is the value of the capacitance seen by the current source? What is the current entering C3? Write an equation for the voltage at Vo for time equal or greater than 0. What is the voltage at Vo when t = 100 milli-second?

Solution

2.1) R1 = 1*10^12 ohm

2.2) Ceq = C1+(C2//C3) = 20u+(10u//10u) = 20u+(20u) = 10u

2.3) Current entering C3, Ic3 = (I1*C2)/(C2+C3) = (1m*10u)/(10u+10u) = 0.5m A