ECE 3054 Electrical Theory
Lecture 4: Kirchhoffs Law
Chapter 1.4, 1.5
1
Recap
Last time we learnt
Current is the flow of electrical charges in a closed loop of wires
(circuit)
Voltage is the measure
Chapter 4 Transients
Chap 4
Summary for Chapter 3&4
Keep solving equations by writing equations by KCL and
KVL
New vi characteristics with capacitors and inductors
New method problem : solving dif
ECE 3054 Electrical Theory
Lecture 15: Capacitance
Chapter 3.13.3
1
Summary for Chapter 3&4
Keep solving equations by writing equations by KCL and
KVL
New vi characteristics with capacitors and in
Sec 2.5 Node and Mesh Analysis
Lecture 11 Mesh current Analysis
Chap. 2.5
1
The nodevoltage analysis
1. Identify circuit elements (source and resistors )
2. Assign polarities for voltage (across the
Lecture 22 First order RL circuits
Chap 4.1
Recap: steady states
RLC circuits with constant voltage source in the long run
Everything will be stabilized
all v and i become constant
i(t)
Steady state
Electrical Theory (ECE 3054)
Instructor: Yunhui Zhu
ECE 3054 Electrical Theory
Lecture 1: Introduction
Chapter 1.11.2
2
Important Information
Time : MWF 9:059:55 Place Goodwin Hall 115
Instructor: Y
Lecture 20 Steady states
Chap 4.2
Chapter 4
Recap for Transient
Currents and voltages in circuits containing inductors and capacitors
demonstrate complex timevarying behavior.
When a circuit is swi
Lecture 21 First order RC circuits
Chap 4.1
Recap: steady states
RLC circuits with constant voltage source in the long run
Everything will be stabilized
all v and i become constant
i(t)
of
transient
Lecture 12 Thevenin Equivalent Circuits
Recap: three ways to solve a circuit
7 step
write KCL equations at
nodes
write KVL equations in
loops
vi characteristic
equations for all
elements
Nodevolt
ECE 3054 Electrical Theory
Lecture 3: Power and Energy
Chapter 1.2 and 1.3
1
Recap
Last time we learnt
Current is the flow of electrical charges in a closed loop of wires
(circuit)
Voltage is the me
Lecture 25 Second order circuit
Chap 4.5
First order circuit
Find out the steady states.
Determine the Ks to match with the two steady states.
K1 K 2 et/
K1 K 2 e0/
K1 K 2
of
transient
Steady state
ECE 3054 Electrical Theory
Lecture 5: Circuit Elements
Chapter 1.6
1
Recap
Last time we learnt
Current is the flow of electrical charges in a closed loop of wires
(circuit)
Voltage is the measure of
Sec 2.45 Node and Mesh Analysis
Lecture 10 NodeVoltage Analysis
Chapter 2.4
1
Recap
We have learnt two methods to solve circuits
1. 7step guaranteedtowork method (the original universal
method)
Lecture 9 Voltage and current division
Chap. 2.3 and 2.4
Recap from Chapter 1: equations
You still need to remember these from Chapter 1
Voltage, Power and Energy
Kirchhoffs law
Ohms law
v iR
Recap
Homework 1 feedbacks
Homework 1 feedbacks
Overall very good job everyone!
Scale 1.75 points for participation, 1.75 points for correctness
Electronic version are printed out this time. Grader has a
Lecture 23 RL and RC circuits
Review and practice
Recap: RC and RL circuit
Capacitors need time to adjust its voltage
RC
Inductors need time to adjust its current
L
R
Recap: RC and RL circuit
Capa
ECE 3054 Electrical Theory
Lecture 2: Circuit,current and voltage
Chapter 1.2
1
Recap
Last time we learnt
Current is the flow of electrical charges in a closed loop of wires (circuit)
+ and  electric
Lecture between 10 and 11
Linear equations set
Recap
We have learnt two three methods to solve circuits
1. 7step guaranteedtowork method (the original universal
method)
2. Equivalent resistance +
Lecture 16 Capacitor circuit
Chap. 3.2
Summary : elements in a circuit
Source: contains separated
electric charges that are eager
to come together
Resistors: Bumpy route for
charges to flow.
Capaci
Chapter 3
Lecture 18
Mutual inductance, Inductor circuit
Chap. 3.57
1
Summary : elements in a circuit
Source: contains or generates
separated electric charges that are
eager to come together
Resist
Lecture 12 Thevenin Equivalent Circuits
Recap
4 methods to solve circuits
1. 7step guaranteedtowork method (the original universal
method)
2. Equivalent resistance + current and voltage division m
1. Sketch the capacitor current,
power, and energy waveforms.
Be certain to include scales.
vs(t) (V)
12
vs(t)
0
2
4
+

6 t (ms)
iC(t) (mA)
t (ms)
0
2
4
6
pC(t) (W)
t (ms)
0
2
4
6
0
2
4
6 t (ms)
wC(t
1. Problem 1.36 of the textbook.
1
Homework 10
ECE 3054
Fall 2017
Jeffrey Mayer 2017. All rights reserved.
2. Problem 1.43 of the textbook.
2
Homework 10
ECE 3054
Fall 2017
Jeffrey Mayer 2017. All r
1. Determine Req.
ECE 3054
Fall 2017
12 W
12 W
12 W
12 W
1
Homework 04
12 W
Req
12 W
12 W
Jeffrey Mayer 20052017. All rights reserved.
2. Assume that you have three resistors with values 1 , 2 , and
1. The capacitor is initially charged to 12 V. Express and
sketch the following using the sets of axes on the next
slide.
a. capacitor voltage vC(t).
b. capacitor charge qC(t).
c. capacitor energy wC(
1. The charge that has passed through a crosssection of a conductor since t =2 s. is expressed as follows:
2t 0
4C
q(t ) 0.5t
C
0t
4e
a. Express the corresponding current i(t) for the interval t [2