Assignment # 01
Basic Electrical Engineering Submission Date: Oct 25, 2010
Resistor Basic, Temperature Effect and Wire Table
1. Use Table 3–2 to find the resistance of 250 m of AWG 8 and AWG 2 solid copper
conductors. Compare the diameters and the resistances of the wires.
2. If AWG 8 is rated at a maximum of 40 A, how much current could AWG 2 handle safely?
3. How much current should AWG 36 copper wire be able to handle?
4. Determine the diameter in inches and in millimeters of circular cables having cross-
sectional areas as given below: (Assume the cables to be solid conductors.) a. 250 CM
b. 1000 CM c. 250 MCM d. 750 MCM
5. A spool of solid copper wire having a diameter of 0.040 inch is measured to have a
resistance of 12.5 Ω (at a temperature of 20°C).
a. Determine the cross-sectional area in both square mils and circular mils.
b. Calculate the length of the wire in feet.
6. Determine the color codes required if you need the following resistors for a project:
a. 33 k Ω +5%, 0.1% reliability
b. 820 Ω + 10%
c. 15 Ω +20%
d. 2.7 M Ω +5%
Ohm’s Law
7. If I = 36 mA when E =12 V, what is I if the 12-V source is
a. replaced by an 18-V source?
b. replaced by a 4-V source?
8. A 20-V source is applied to a resistor with color bands brown, black, red, and silver
a. Compute the nominal current in the circuit.
b. Compute the minimum and maximum currents based on the tolerance of the
resistor.
9. A 2.2-k Ω resistor with a tolerance of +5% is connected to a 12-V dc source. What is the
possible range of power dissipated by the resistor?
10. Determine which, if any, of the following resistors may have been damaged by
overheating. Justify your answer.
a. 560 Ω, 1⁄2W, with 75 V across it.
b. 3 Ω, 20 W, with 4 A through it.
c. 1⁄4W, with 0.25 mA through it and 40 V across it.
Series Circuits and KVL
11. Solve for the unknown voltages in the circuit of Figure.
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