EK#307:
Electric#Circuits
Fall$2017
Lecture$21
Nov$28,$2017
Milos$Popovic
Department$of$Electrical$and$Computer$Engineering
Boston$University
Administrivia
• HW9$due$Thursday
• Emailed$grade$summary$to$everyone
• Any$questions$or$errors$to$report$– please$email$me.
• 5$lectures$left:$$we$will$cover$Chapters$9,$10$and$14
Last#Lecture#(20):##Chapter#8#– 2nd
order#ccts
1. Finished*Solving*2nd order*ccts – Sec*8.578.8
2. Started*Chapter*9*– Phasors*&*Sinusoidal*Steady*
State
Summary
Overdamped
Critically$damped
Underdamped
Step#response#of#RLC#circuits
Step#Response
Step#Response
General#2nd#order#circuits
Sinusoids#and#Phasors
Chapter$9
Sinusoids#and#Phasors
• aka$AC
Sinusoids#and#Phasors
• aka$AC
Sinusoids#and#Phasors
Sinusoids#and#Phasors
Phasors
Phasors
Add*in*component*form.
Multiply*in*polar*form.
Phasors#and#sinusoids
Leading#and
Lagging#Phase
Phase
Time#and#frequency#domains
v(t)
V
Instantaneous/time$domain
phasor/frequency$ domain
Time$dependent
Time$independent
Always$real$valued
Complex$number$ in$general
Differentiation#and#integration#in#
time,#in#the#phasor#domain
Phasor#Circuit#Laws
Resistor
Inductor
Capacitor
Concept#of#impedance
Impedance#and#admittance
conductance
resistance
reactance
susceptance