ELEC130 Electrical Engineering 1

Gunilla Burrowes Fernando MartinezEA G24 EE 102(p) 4921 6352 4921 6149email gunilla@ee fmm@ecemailMon &Fri 2-3pm Help Desk

HELP - EA G08 - during office hours

Material 5 modules

1 - Introductory Circuit Techniques Week 1 & 2 2 - DC Circuit Tools Week 2 3 & 4 3 - AC Circuit Tools Week 5 & 6 4 - Applications in Power Week 7 & 8 5 - Applications in Communications & Week 9 10 11

Instrumentation Week 12 & 13

Electronic Workbench: Faculty PC’s Rm. ES210 - Go to Diomedes Login: cstudentnumber Password: access keys on students card +

daymonth (ddmm) of birth

TopClass: http://www.newcastle.edu.au:86/topclass/ Username: first name.last name Password: date of birth ddmmyy

Email: first name.last name@studentmail

Lectures

2 hour / week for 13 weeks - Monday 5 -7pm

Quizzes - Weeks 3 6 8 11 13

Course Information Booklet

Student Responsibility

Survey

Student Responsibility

Expect CIVIL Behavior

Work consistently

Progressive assessment

Teaching / Learning

Rote Learning

Where to go for help

Material may not always seem relevant

Its Up To You

The onus is shifted to you to “learn” (independently)

Majority of learning will take place when you tackle the subject material

BURY NOW the natural tendency to assume a passive role (waiting to be taught)

Text & References

Course information Booklet & Safety Notes $12.00 Purchase after this lecture - Foyer EA

Several Alternative Texts Floyd - Principles of Electric Circuits Dorf - Introduction to Electric Circuits Hambley - Electrical Engineering Johnson - Electric Circuit Analysis

Student Problem Sets - Library Text references Study Guide

Tutorials

1 hours / week. Start next week Check your group on Noticeboard Foyer EA

You must Enroll Tonight

ASK QUESTIONS Electronic Workbench - ES 210

Introduction - Tutorial 2 Week 3 Matrix - textbook

Tutorial 1

Laboratory

2 hours / week - start next week Voluntary Laboratory THIS WEEK Check your group on Noticeboard Foyer EA

You Must Enroll Tonight - Foyer EA

EE 103(a) 9 laboratory exercises (Lab 1 goes for 2 weeks) 2 practical tests - 15 % each (Total 30%) All experiments are considered “examinable” Keep a Laboratory diary

Laboratory

Attendance Sheets

Safety - notes will be attached to course information booklet- READ THEM

Use Common Sense

Keep the Laboratory Tidy

BE PREPARED

Help Desk - EE 102 / EE 103

Monday 9 - 11 am

Wednesday 8 - 9 am 1 - 2 pm 8 - 9 pm

Assessment

Final grade for ELEC 130 will be

5 quizzes @ 4% each 20% 2 laboratory tests @ 15%30% June Exam @ 50% 50%

Engineering

Concerned with creation of solutions to problems, based on science and technology

Systems Engineering emphasises a wholistic design methodology encompasses the whole life cycle of the product

Role taken on by engineering in technology-based enterprises creative element to convert a need into a service or

product integration of all processes into a single coherent process

Multi-disciplinary & Integrating Nature

Economics Manufacturing

Social Reliability

Legal Maintainability

Environmental Human Engineering

Engineering as a Process

Technology, R & D

Market

Marketresearch Engineering

Marketing,sales andsupport

Changing Nature of Engineering

The essence of engineering is a product of the human mind

For the mind to be creative, it must operate on concepts (not just facts)

Swing back to the wholistic view complexity of the interaction with society rapid and fascinating development of

engineering science

Engineering

Involves two complementary subjects

the body of knowledge known as engineering science

the process of applying that knowledge

Aims of ELEC 130

To study the concepts of basic electrical elements & circuits

Start with laws of physics to derive simple ‘rules’ for electrical circuits

Same rules apply to ‘light’ current i.e. computers, communication ‘heavy’ current i.e. power grid, motors

Overview of DC Circuits

Units & NotationWhat is a circuit?What is Charge / Current?What is Voltage?Voltage & Current sourcesPowerResistanceOhm’s Law

Units

SI system - kg,m,sOthers derived from these - Volts, FaradsScaling of Units

p pico 10-12

n nano 10-9

micro 10-6

m milli 10-3

_ unit 1 K kilo 103

M mega 106

G giga 109

Notation

Time varying quantities - lower casee.g. v(t), i(t) sometimes assume time - v(t) = v

Time invariant quantities - upper casee.g. V, R,

Remember to include units of measuree.g. 15 Volts

What is a circuit?

In ELEC130 we assume that a circuit comprises of two or more elements connected by electrical conductors. Electrical conductors allow electricity to flow

(unimpeded) between elements

Electricity must flow in a CLOSED path or circuit

Open Circuit

A ‘Break’ in a circuit is called an open circuit

Short Circuit

A ‘bypass’ of an element is called a short circuit

Different Geography

Two circuits may have the same topology but different geography

Charge

Charge is the phenomenon giving rise to those forces observed between electrical charged bodies. There are 2 kinds of charges: pos & neg

Symbol Q (constant) or q(t) (time varying)

Defined in terms of the charge on 1 electron ~=1.6x10-19 Coulombs

or stated as Charge on 6.2x1018 electrons is 1 Coulomb

Current Motion of charge constitutes an electric current

Conventional current is the flow of positive charges

Electron current is negative charges

Measure of rate of flow of charge

1 Ampere = 1 Coulomb/sec or Charge is the sum or ‘accumulation’ of current

Symbol I i(t)

Current cont..

The primary purpose of electric circuits is to move or transfer charges along specific paths

3 Acircuit

- 3 Acircuit

=

Voltage

Fix one Coulomb of charge in space … energy input (work) is required to bring another Coulomb of charge from a point A to a new point B closer to the fixed charge ……. the potential energy difference between points B & A is known as voltage:

1 Volt = 1 Joule / Coulomb

Charge tends to flow from a higher voltage (potential) to a lower voltage - resulting charge flow is current

Symbol V v(t)

Power Power is energy / time

P = VI Watts

p = v(t).i(t) W

i.e. need voltage and current (at the same time) to do work

Power can be +ve and -ve; it can be ‘absorbed’ or delivered

Symbol: P p(t) Units: Watts W

Power Convention

If v(t) 0 and i(t) 0 then p 0

Power is said to be absorbed by the circuit

NB polarity of voltage and direction of current

+

v(t)

-

i(t)

Circuit or element

Voltage & Current Source

An ideal voltage source maintains its stated voltage regardless of the load attached

Independent voltage source

An ideal current source supplies its stated current regardless of the load attached

independent current sourceVA VA VAIB IB

Ohm’s Law

Some materials are good conductors of electricity, some are poor

In a ‘good’ conductor, the current flowing through the conductor is (approx.) proportional to the voltage across it.

Constant of proportionality is known as resistance, given symbol is R

Ohm’s Law: v(t) = R i(t)

Example

4 V

10

i(t)