# HW2 - What is the cross sectional area of electrodes with a...

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HW #2 1. An incandescent bulb with a tungsten filament operates at temperature ranging between 1800K-3200K. When operated at 1800K, the color of the bulb is reddish. Bright yellowish white light is emitted from the bulb when operated at 3200K. The resistivity of tungsten as a function of temperature is provided in Table 2 at http://hypertextbook.com/facts/2004/DeannaStewart.shtml . If the relationship between resistance and temperature is given by 2 4 2 8 4 2 10 67 . 5 2 r l R K m W x T R rl I Determine the resistance of the filament at 3200K and current required to have the filament reach 3200K if the length and diameter of the filament are l = 580mm and 2 r = 45 m, respectively. 2. The Human Body Model has been developed to model how humans can damage devices by electrostatic discharge (ESD). The capacitance of a human is modeled as a 100 pF capacitor ( http://www.esda.org/basics/part5.cfm ). Equivalent circuits are designed to help evaluate the robustness of circuits to shocks caused by charged humans touching them.
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Unformatted text preview: What is the cross sectional area of electrodes with a mylar dielectric separating the electrodes (100nm thick, mylar = 3.2) needed to fabricate a capacitor to simulate the capacitance of a human? 3. Determine the frequency (f o ), and angular frequency ( o ), at which the impedance of a 10mH inductor equals the negative of the impedance of a 50 F capacitor. As the frequency increases, which impedance becomes larger the impedance of the inductor or the capacitor? 4. Calculate the phasor notation for the following voltages. a. V(t) = 30 cos(60t + 120 o ) b. V(t) = -18 cos(1000t 30 o ) c. V(t) = 12 sin(100t) d. V(t) = -12 sin(100t) 5. Calculate the current in phasor notation that flows through the components below that has a voltage of o V 45 100 with an angular frequency of 2 (60Hz) applied across it. a. 300W b. 0.3mH c. 47 F...
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## This note was uploaded on 07/05/2010 for the course ECE 2984 taught by Professor Meehan during the Spring '10 term at Virginia Tech.

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