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Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013
EE for CE Course Outlines
MID TERM I
Dr. Basim Zafar
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 2
EE for CE - MID TERM I
1. Frequency.2. Resistance, Capacitor & Inductors in Parallel & Series.3. Ohm’s Law.4. Two special resistor values (Open & Short Circuit).5. Electric Power Calculator6. Kirchhoff’s Current & Voltage Law7. Voltage & Current Divider8. Circuit Analysis using KVL & KCL.9. Linearity and Superposition10. Thévenin’s Theorem 11. Source Transformations
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 3
1. Frequency
• Frequency = Number of cycles per second
voltvolt
time
time
Tf
1Unit : Hertz
a. Calculate the frequency of a signalb. Draw a signal with a certain frequency.
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 4
2. Resistance, Capacitor & Inductors in Parallel & Series.
• Calculate Resistance, Capacitor & Inductors in Parallel & Series combinations.
• Capacitors: Passive electronic component consisting of a pair of conductors separated by a dielectric (insulator). Measured in Farad (F)
– Uses: to block DC, to filter noise, to smooth power supplies, to tune radio channels & in memories.
• Inductors: Passive electrical component that can store energy in a magnetic field created by the electric current passing through it. Measured in Henry (H)
• Uses: Resists (reacts) AC current with delay– no effect when DC is used
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 5
3. Ohm’s Law.
• Ohm’s Law: The voltage across a resistor is directly proportional to the current moving through the resistor
• V = I
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 6
4. Two special resistor values (Open & Short Circuit).
Circuit
Short
Circuit
Open
0v
0i
0R R
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 7
5. Electric Power Calculator
• Power is the time rate of change of energy• Unit: watts (W)• P=VI = =
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 8
6. Kirchhoff’s Current & Voltage Law
• Kirchhoff’s Current Law : “The sum of the current entering a node equal to the sum of the currents leaving.”
• Kirchhoff’s Voltage Law : “Sum of the voltage drops around a circuit equal zero.”
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 9
7. Voltage & Current Divider
21
11 RR
Rvv s
21
22 RR
Rvv s
21
21 RR
RII T
21
12 RR
RII T
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 10
8. Circuit Analysis using KVL & KCL.
• To solve for all currents in more than one source circuit:
1. Count nodes minus one (possible ground)2. Mark a current for each branch (name and
direction)3. Write KCL equations for each node4. Count the loops5. Write the KVL equations for each loop6. Solve for all unknowns
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 11
9. Linearity and SuperpositionLinearity procedure:
1. Give to Vo any arbitrary value (e.g., V’out =1 )
2. Compute the resulting source value and call it V’_s
3. Use linearity. kkVkVVV outSoutS ,''''
Circuit with currentsource set to zero(OPEN)
1LI
1LV
Circuit with voltage sourceset to zero (SHORT CIRCUITED)
2LI
2LV
SOURCE SUPERPOSITION
= +
2121LLLLLL VVVIII
Electrical Engineering for Civil Engineer Dr. Basim Zafar Spring 2013 Slide 12
10. Thévenin’s Theorem • Thevenin's Theorem is a way to reduce a network to an equivalent
circuit composed of a single voltage source and a series resistance.
Steps to follow for Thevenin's Theorem:• (1) Find the by removing the load resistor from the original circuit
and calculating voltage across the open connection points.
• (2) Find the by removing all sources in the original circuit (voltage
sources shorted and current sources open) and calculating
• (3) Draw the Thevenin equivalent circuit
Thévenin Equivalent Circuit
VTh
RTh
Resistive Circuit