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Power Supply Challenge Manual

Power Supply Challenge is a set of simulated power supply circuits designed to

provide realistic troubleshooting experiences. Power Supply Challenge is not a

self-instructional program or a tutorial. Students should have a working

understanding of linear power supply circuits before using Power Supply

Challenge. Each run of the program presents problems in a new order with new

parameters. Activities are graded and scored in real time by the program. Time on

task is measured in addition to scores. Scores can be stored on a diskette or a

certificate can be printed at the conclusion of each exercise. The Power Supply

Challenge program can also be used effectively to perform classroom

demonstrations using a LCD video projector or large screen monitor. The activities

included in Power Supply Challenge are Half-Wave Troubleshooting with an

Oscilloscope, Full-Wave Troubleshooting with an Oscilloscope, Bridge

Troubleshooting with an Oscilloscope, Half-Wave Troubleshooting with a

Voltmeter, Full-Wave Troubleshooting with a Voltmeter, Bridge Troubleshooting

with a Voltmeter and Measurements on Good Circuits.

 

 

Much effort went into making this program very visual and interactive. This program

is designed for users who may have little experience with using computers and

computer software. Power Supply Challenge provides an environment that allows

students to learn by experiment and discovery.

 

New parameters are selected every time an exercise is used. This allows students

to practice a particular exercise numerous times without boredom and memorizing

the answers. The troubleshooting exercises have thousands of variations. The

program measures the time that is required to complete each exercise. Students

have the option to print a certificate showing Topic Title, Student Name, Student

ID, Date/Time, Score, Time on Task, and a Validity Code. The Validity Code can

be used to verify that the certificate is authentic. In addition, students have the

option to have scores recorded in a disk file. The "Check Certificate Validity"

option can be used to determine if a certificate has been altered.

 

Using the Windows Calculator

 

The Windows calculator can be used with this program. The following procedure

can be used to set up the calculator. Select PROGRAMS, then ACCESSORIES,

and then CALCULATOR before starting the program. The Windows calculator

should be displayed on the screen. Select the block with the "line" in the upper

right corner of the calculator. This reduces the calculator to an icon on the task

bar. Start execution of the Power Supply Challenge program. When you want to

use the calculator, press the Windows key or Ctrl/Esc to display the task bar.

Click the calculator button. You can also hold down the Alt key and press Tab

until the calculator icon is highlighted. You may need to review your Windows

manual on switching Windows tasks if these brief instructions are difficult to

follow.

 

Grading

 

Each exercise has ten defective power supplies to troubleshoot. You are given 13

points for each power supply. Moving the red test lead costs one point. Making a

measurement with the ohmmeter costs two points. Selecting the wrong answer

costs five points. Your score for an item can't be negative or less than zero.

Therefore, you can score up to 130 points by selecting the correct answer on all

ten problems in an exercise. This, of course, would require all guess work and

luck beyond all imagination.  Some tests will always be required. Practical scores

will be much less than 130 points for even an expert troubleshooter. The program

also measures the time required for you to complete an exercise. In addition to

doing accurate work, good troubleshooters must complete the work in a

reasonable amount of time.

 

 Storing Scores on Disks

 

Student scores can be stored on a diskette. A diskette must be in the drive prior

to choosing this option. Errors and possible loss of the score data may occur if

the drive does not contain a diskette. The file generated by the disk storage

feature is given a DOS compatible file name, gxxxxxxx.xx, where the lower case

"g" is always the first letter in the file name. The xxx… is the student ID that is a

sequence of two to nine numeric digits. The file is a simple ASCII text file that can

be read and examined with any word processor. Do not examine and resave a

student grade file under the original name with a word processor! This can make

the file appear corrupted by the score printout utility. Word processors inject

formatting characters into a file. This program calculates and stores a code with

each record in the student score file. This Validity Code is a simple encryption

signature designed to reduce the possibility of file entry alteration and the

generation of duplicate records. The Validity Code provides some low-level security

but is certainly not hack proof. The validity of records can most easily be checked

by use of the "Print Grade File" option.  This option produces a formatted printout

of a selected student grade file. Never attempt to use this option to print any other

file type. Each grade record in the file is validity checked with "E!" printed after any

record failing the validity test. The routine also checks for duplicate records. A "D!"

is printed after each duplicate record is found.

 

This program stores student grade files on diskette drive A: by default. One may

want to store grade files on another drive or directory under some circumstances.

See the next paragraph for instructions on changing the path for student grade

files. The student records will be stored in a file named gxxxxxxx.x where the x(s)

represent the digits of the students ID Code. The ID Codes are a series of numeric

digits. The ID Code must contain at least 2 digits long but no longer than 9 digits.

A DOS filename is generated with an appended lower case g followed by up to 7

digits. Any additional digits are added after a period to produce a legal DOS file

name. The file is a simple ASCII text file that can be viewed with any word

processor. The score printing options in this program can detect modifications to

the file. In addition, individual records in the file can be validity checked by use of a

procedure in this program. These validity-checking procedures are not intended to

offer high data security.

 

Initial Option Settings

 

This program reads the file "options.ini" on each startup. The file options.ini is

located in the same directory as the program file. The first entry sets the condition

for the certificate printing option default condition. The two possible settings are:

 

CERTIFICATES ON or CERTIFICATES OFF

 

The second entry in the  "options.ini" file sets the default condition of the disk

storage feature for grades. The two possible settings are:

 

DISK STORAGE ON or DISK STORAGE OFF

 

The third entry in the  "options.ini" file sets the default condition of the Wallpaper

option. The possible settings are:

 

WALL PAPER ON or WALL PAPER OFF

 

All characters in the above initialization options must be in upper case characters.

All characters are significant including spaces. Any error in spelling, spaces, or

case will cause the option to default to the ON setting.

 

Line 4 of the option.ini file contains the path for student grade file storage. Errors in

formatting this line may cause program execution errors. Any directory or

subdirectory paths given must exist prior to program execution. The program will

not create directories. No entry on line 4 will cause the program to default to a:\ as

the path for student grade storage. A few examples of paths and explanations are

given below.

 

b:\

 

The student grades will be stored on drive b:

 

c:\stuff\

 

The student grade files will be stored in the "stuff" directory of c: drive. Caution!

You must create the "stuff" directory prior to running the program.

 

c:\records\student\

 

Grade files will be stored in the "student" subdirectory of the "records" directory of

c: drive. Again, you must create the directory structure prior to running the

program.

 

Diskette Precautions

 

Floppy disk data is easily corrupted or destroyed in several ways. Students should

be strongly advised to make backup copies of their floppy disk grade files

frequently to avoid data loss problems. Teachers can prevent massive data losses

by processing student floppy disk files often.  This also encourages students to

have assignments up to date.

 

Video and Hardware Considerations

 

The evaluation version of the program should be tested on target machines prior

to licensing the program. The best results for

graphics is obtained with a 16-bit or 24-bit color setting and either 480x640 or

600x800 resolution. The program can be use with any resolution of 480x640 or

higher. There will be some distortion caused by palette flash when used with video

set to 256 colors. Where resolutions above 480x640 are used, the working window

is centered with the unused area wallpapered by default with the image chips.bmp

found in the Power Supply Challenge install directory. The wallpaper will produce

strange but interesting color patterns on systems set to 600x800 or higher

resolution with 256 colors because of palette flash. This will not affect program

operation. This program can be used effectively in 16-color mode. However, some

of the animations and non-essential screen elements will be difficult to see clearly.

 

The file chips.bmp can be deleted or renamed to allow normal task switching as

no wallpaper will be displayed. This can be useful to more advanced students who

are familiar with task switching.  The wallpaper is useful to beginners because

accidental task switches are unlikely.  Another bitmap file can be substituted for

chips.bmp. The file will be tiled as wallpaper across the unused portion of super

VGA displays. Some institutions may want to display school or department logos

on the wallpaper.