EGR 203 Electric and Electronic Circuits Assignment 3(c)

  1. Given the circuit below, with R=22.8 kΩ and C = 10 nF. Find the time constant τ and the equation for the voltage across the capacitor as a function of time if the voltage input is 2 V for t ≤ 0 and 5 V for t > 0. Plot the results for a time of at least five time constants.

  2. Do the problem above in Multisim, using a pulse source and both oscillocope simulation and transient analysis (see RC_multisim.pdf).

  3. Do the following (15 points)
    1. (Rizzoni 5.11) Determine the initial and final conditions for the circuit below.
    2. (Rizzoni 5.21) Just before the switch is opened at t = 0, the current through the inductor is 1.70 mA in the direction shown.
      Did steady-state conditions exist before the switch was opened?
    3. Find an expression for the current through the inductor for t > 0.

    VSLR1 R2R3
    12 V0.9 mH 6 kΩ 6 kΩ 3 kΩ

  4. Do the following (15 points)
    1. (Rizzoni 5.12 ) Determine the initial and final conditions for the circuit below.
    2. (Rizzoni 5.23) Find the current through the capacitor just before and just after the switch is closed at t = 0. >
      Assume steady-state conditions exist before the switch was closed.
    3. Find an expression for the voltage Vx across the capacitor for t > 0.

    VSCR1 R2
    12 V0.5 μF 0.68 kΩ 1.8 kΩ


Maintained by John Loomis, last updated 1 October 2014