CIRCUITS by Ulaby & Maharbiz
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
LECTURE 1. CIRCUIT TERMINOLOGY
06/18/2013
ECE225 CIRCUIT ANALYSIS
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Chapter 1: Circuit Terminology

Electronics

Devices – active vs. passive
 Circuits
 Systems
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Cell-Phone Architecture
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Units, Multiples, Notation
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Tech Brief 1: Micro- and Nanotechnology
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Tech Brief 1: Moore’s Law
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science
Press
Tech Brief 1: Micro- and Nanotechnology
Tech Brief 1: Heat power Density by CPU
All rights reserved. Do not
reproduce or distribute.
© 2013 National Technology
and Science Press
Circuit
Representation
All rights reserved. Do not
reproduce or distribute.
© 2013 National Technology
and Science Press
Common Circuit
Elements
All rights reserved. Do not
reproduce or distribute.
© 2013 National Technology
and Science Press
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science
Press
Circuit Topology
Branch: single element, such as a resistor or source
Node: connection point between two or more branches
Extraordinary Node: connection point between at least 3 branches
Loop: closed path in a circuit
node
branch
loop
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Terminology
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Planar Circuits


Planar circuits: can be drawn in 2-D without
branches crossing each other
Whenever possible, re-draw circuit to simplify!
Charge & Current

Unit of charge = coulomb
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Electron Drift
Response time = 0.2 microsecond
Actual travel time = 10 days!!
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Current
All rights reserved. Do not reproduce or distribute.
© 2013 National Technology and Science Press
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Example 1-1: Charge Transfer

Given:
Determine: (a) q(t)
(b)
Solution:
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Example 1-1: Charge Transfer (cont.)
(b)
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Voltage & Power
Reference/Ground



Choose reference
point for potential
Assign potential
at reference
= 0,
f
0
called ground
Now all potentials
are relative to
ground terminal
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Measuring Voltage & Current


Voltmeter: measures voltage without drawing current
Ammeter: measures current without dropping voltage
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Open Circuit & Short Circuit


Open circuit: no path for current flow (R = )
Short circuit: no voltage drop (R = 0)
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Power
Rate of expending or absorbing energy
P
dw dw dq

 vi
dt dq dt
P  0
Energy
conservation
Units: watts
One watt = power rate of one joule of work per second. 1 W = 1 A x 1 V
Passive Sign Convention
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Example 1-4: Energy Consumption

Given: Resistor consuming 20 W before switch turned off at t = 0.

Also
Determine: Total energy consumed by resistor after t = 0.
Solution:
((before t = 0))

All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Circuit Elements: Independent Sources
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Circuit Elements: Dependent Sources
I-V for Sources

Current/voltage fixed
for independent sources
 What
does a non-ideal
source look like?

Dependent sources vary
with reference
voltage/current
 What
slope?
are units for
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Equivalent Circuit Using Dependent Source
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Example 1-5: Dependent Source

Given:
Source is CCVS
Determine:
Solution:
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press
Switches
Summary
All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press