ECE
HW6_Soln

# HW6_Soln - Escuti/Brickley ECE200 Fall 2008 Homework 6...

• Notes
• 8

This preview shows pages 1–3. Sign up to view the full content.

Escuti/Brickley ECE200 – Fall 2008 – Homework 6 Solution Electric Power Page 1 of 8 Problem 1: [12 pts] Find the DC and RMS value of the following signals: (f) v ( t ) = –2V Solution: (a) through (d) Vdc = 0V, Vrms = 10V/sqrt(2) = 7.07V (e) Vdc = 2V, Vrms = sqrt(2 2 +7.07 2 ) = 7.28V (f) Vdc = –2V, Vrms = |–2V| = 2V Problem 2: [10 pts] Consider a standard light bulb rated at 60W assuming 120Vrms/60Hz (standard household voltage). Due to excessive electricity usage in a neighborhood, the RMS value of the AC voltage delivered to the houses drops from 120 to 115 V. What is the power consumed by the light bulb under this circumstance? (Note that the answer is NOT 60W, and that you may assume that the internal resistance of the light bulb is constant at all voltages). Solution: We note that 60 W is the real power, designed for 120V/60Hz. The internal resistance of the light bulb is given by: If the RMS voltage applied is 115 instead of 120, the power is given by:

This preview has intentionally blurred sections. Sign up to view the full version.

Escuti/Brickley ECE200 – Fall 2008 – Homework 6 Solution Electric Power Page 2 of 8 Problem 3: [16 pts] Solution: a) Sketch the current waveform, i(t) flowing through the resistor. It has the same shape as the voltage waveform due to Ohm’s Law. When the voltage is 7 V, the current is 7/10 = 0.7 mA When the voltage is -2 V, the current is -2/10 = - 0.2 mA b) Find the average or DC value of the current flowing through the resistor.
This is the end of the preview. Sign up to access the rest of the document.
• Fall '07
• Escuti
• ohm, 1 volt, 0.4 MW, 0.4mw, 2.86 W

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern