EGR203 Assignment 3 (a)

  1. Suppose we have two Aluminum foil sheets (250 mm by 250 mm square) with a 12-µm thick food wrap dielectric (estimated relative dielectric constant of 2.5). Calculate the capacitance.

  2. Given two capacitors, one of 15 µF and the other 30 µF. Find the effective capacitance if the capacitors are connected in series (end-to-end) and if they are connected in parallel (side-by-side).

  3. A voltage of 50 V appears across a 10-µF capacitor. Determine the amount of charge and the energy stored on the capacitor.

  4. Find the equivalent capacitance between terminals x and y in the circuit below.

    where

    C1C2C3 C4C5C6
    15 μF10 μF3 μF12 μF1 μF5 μF

  5. Suppose the time-varying voltage across a capacitor C = 10 µF is V = 20 sin(200t). Find the time-varying current.

  6. (Rizzoni 4.21) The voltage across and the current through a capacitor are shown below. Determine the value of the capacitance.

  7. Suppose you have a Wheatstone bridge, shown below, with R3 = R, the other resistances equal to 10 kΩ and Vs = 5 V. Plot the bridge voltage as a function of R for 5 kΩ ≤ R ≤ 20 kΩ.

  8. (Rizzoni 3.60) It is sometimes useful to compute a Thevenin equivalent circuit for a Wheatstone bridge. For the circuit below,

    1. Find the Thevenin equivalent resistance seen by the load resistor RL.
    2. If VS = 12 V, R1 = R2 = R3 = 1 kΩ, and R4 = 996 Ω is the resistance found in part b of the previous problem, use the Thevinin equivalent circuit to compute the power dissipated by RL = 500 Ω.
    3. Find the power disspated by the Thevinin equivalent resistor RTh with RL included in the circuit.
    4. Find the power dissipated by the bridge without the load resistor in the circuit.

  9. (Rizzoni 3.27) Find the current i in the circuit below. Let VS = 5.6 V; R1 = 50 Ω; R2 = 1.2 kΩ; R3 = 330 Ω; R4 = 440 Ω; IS = gm V2 where gm = 0.2 S.


Maintained by John Loomis, last updated 25 September 2014