ELEC 226: Homework Assignment 7

ELEC 226, Spring 2009
Prof. Rich Kozick

Homework 7

Date Assigned: Wednesday, February 26, 2009
Date Due: Wednesday, March 4, 2009 (items 2 and 3 are due in class at 9:00 AM)

Reading: For March 2 and 4, please review Chapter 6 and begin reading Chapter 7, Sections 7.1, 7.2, and 7.3.
Please solve a variation of Problem 1 on Exam 1 (the solution to Exam 1 is posted on Blackboard). The circuit for this problem is an ideal voltage source v₁(t) in series with a capacitor (C farads) in series with an eleven ohm resistor. The voltage v₂(t) is measured across the resistor so that v₁(t) = v_C(t) + v₂(t) where v_C(t) is the voltage across the capacitor.
The voltage waveforms for v₁(t) and v₂(t) in sinusoidal steady-state are shown below. Please estimate the value of the capacitance, C (in farads).
Please solve a variation of Problem 3 on Exam 1. The sinusoidal source voltage is 120 V (rms) with frequency 60 Hz. Load 1 is a 40 ohm resistor in series with a 53.1 mH inductor.
- For Load 1, compute the following quantities: Complex power, average power, apparent power, peak amplitude of the source current (i_s(t)), power factor (include lagging/leading), peak value of instantaneous power.
- Let us define Load 2 as Load 1 in parallel with a capacitor with value C. Find the value for C (in farads) so that the power factor equals 1 for Load 2.
- For Load 2, compute the following quantities: Average power, apparent power, peak amplitude of the source current (i_s(t)), peak value of instantaneous power.
- For Load 2, draw a phasor diagram showing the phasors for the source voltage, source current I_s, and the currents I₁ and I₂.
If you did not submit the summary pages for your lowpass and highpass filters in Lab 4, then please submit them by Friday, March 6 at 10 AM.

Thank you.