Electrical Principles 1 - 7793A, Applied Electricity 1 - 7793AV Mt Druitt College of TAFE Dept. Electrical Engineering

Electrical Principles 1 - 7793A, Applied Electricity 1 - 7793AV

Mt Druitt College of TAFE

Dept. Electrical Engineering

© Mike Stacey 2008 2

Assessment

Theory Test 1: 25% Theory Test 2: 50% Practical: 25%

May consist of 2 separate tests


How to pass the subject – your responsibility Access the web site at

http://wsiee.wikispaces.com/ every couple of days for: Weekly notes – powerpoint slides in *.ppt and *.pdf format: Print the pdf versions and bring to class BEFORE each

class. Other material such as revision questions for tests and

related material It can all be found on a page dedicated to each week of the

subject. You should print this page also. Store all hard copies in a folder and stay organised!


Web site – home page


Web site – class notes index


Web site – Compulsory Core index


What you require

The workbook: Student Workbook available from the college bookstore: "Electrical Principles for Advanced Diploma Courses, Workbook 1"

Text: (Recommended) Phillips, Peter 1996, Electrical Principles 1 ISBN 0 170092127 Thomas Nelsen, Melbourne, Victoria.

Weekly notes downloaded and printed from the website A Calculator: Capable of performing rectangular -> polar

conversions, logs, trig, base N number systems. Folder to store weekly material and pens and paper


Topics

Basic Electrical Concepts Ohm's Law Power Series Circuits Parallel Circuits Series - Parallel Circuits Voltage Sources Effects of a Current Electrical Measurement Resistance Practical Resistors Sources of electrical energy


Today’s Topics

See workbook pages 2.1 - 2.6 The Atom Potential difference, current, resistance Source of electricity Circuit diagrams Current direction Current effects SAFETY Maths review Homework: Complete Tutorial 1 (P 2.8) and Safety Tutorial

(P2.7) for next week


The Planetory Atom (ref P2.1)

An atom consists of a central nucleus surrounded by orbiting electrons. Electrons are negatively charged and protons positively charged,

Figure 1


Potential Difference, Current and Resistance (ref P2.1)

A potential difference exists between negatively charged and positively charged bodies.

Resistance is the ability of a material to oppose the flow of electrons.

Figure 2


Water Analogy for Current Flow [1]

A water-pressure difference causes a current of water to flow between the two tanks. The thick pipe passes a larger current than the thin pipe.

Figure 3


Water Analogy for Current Flow [2]

Figure 3


Basic Sources of Electricity (ref P2.2)

Zinc-carbon voltage cell

Chemical action removes electrons from the carbon. Carbon rod is then positively charged. Electrons accumulate in the zinc hence it is negatively charged.

There is a potential difference, or voltage, between the +ve and –ve terminals.

Figure 4


Basic Electric Circuit (ref P2.2)Switch open: no conduction path between battery terminals. No current flow.

Switch closed: potential difference between battery terminals causes a current to flow from negative terminal, through the lamp and switch, to the positive battery terminal.

Result: the lamp lights up.

Figure 5


Circuit Diagrams (ref P2.2)

Figure 6


Current Direction (ref P2.3) & Effects of Electric Current Current Flow

Conventional Current direction: Positive to Negative Direction of Electron Flow: Negative to Positive

Effect of electric current Heat Magnetic field Chemical effects Muscle contraction


Conditions Required for Current Flow (ref P2.3)

Source of EMF Conducting path

Documents

Electrical Principles 1 - 7793A, Applied Electricity 1 - 7793AV Mt Druitt College of TAFE Dept. Electrical Engineering