SOLVE IT

What really happens when you divide something by a zero

noreply@blogger.com (Unknown) — Wed, 20 Mar 2013 02:01:00 +0000

(Disclaimer: This post is merely trying to describe why result of division by zero sometimes written or assumed as infinity. It does not describe detail mathematical aspect of zero division. )
We usually say it is not possible to determine the result of zero division. Sometimes we write the result as an infinite number. In my early days of math education I always wondered why we say it undefined and write as infinity in mathematical expressions. One possible reason is to assume infinity itself as an undefined number or entity. But there was another explanation.

PHP code for prime number detection

noreply@blogger.com (Unknown) — Wed, 06 Feb 2013 04:49:00 +0000

Find Prime number using PHP code

Here is the procedure the determine if a number is prime or not. I will code it using PHP, but let me show you the algorithm first so that you can rewrite it using any language.

Algorithm:
1. Take the number to be decided as a variable "i"
2. If the number is 1 or 2, it is prime. So flag it as prime under a variable "flag_one". If this variable is TRUE, we will declare the number as prime.
3. If the number is completely divisible by 2, it is an even number and is not prime. Flag it as false in this case.
4. If the number is not divisible by 2 (and not equals to 1, handled in step two), it must be odd. Now we need to check if the number is divisible by any number which is lower in value than the input number. Actually it will suffice to check any number less than half of the input number. For example, if the input number is 17, we need to check untill 17/2=8.5, rounded to 9 and check if 17 is completely divisible by any number starting from 3 to 9. If it is, we do not need to check it any further and declare it as prime under the variable "flag_one". If not, we need to check it untill 9. Finally, if we do not find any number that divides the input with a remainder zero we need to declare the input as NOT prime.

Code:

Fibonacci code in Python language

noreply@blogger.com (Unknown) — Tue, 03 Apr 2012 10:16:00 +0000

Code to output Fibonacci number in Python

Fibonacci code can be written in Python language very easily and efficiently.
It can be done recursively or non-recursively. I have provided non recursive examples in other post, hence this Fibonacci code example is written in recursive manner.

Code:

def fib:
if (n==0):
return 0
elif (n==1):

PHP code for Fibonacci series

noreply@blogger.com (Unknown) — Thu, 15 Mar 2012 06:39:00 +0000

Fibonacci code in PHP

Here is the PHP code for Fibonacci series. This will just print the series in screen. If you need the sum upto n-th Fibonacci series number, please let me in the comment box. I will provide the code ASAP.

Code:

<?php 

   $n=10;//n-th Fibonacci number

     for($a=1,$b=1,$c=0,$i=0;$i<$n;$i++)

        {

          $c=$a+$b;

          if ($i==0) echo $a.' '.$b.' ';

          $a=$b;

          $b=$c;

          echo $c.' ';

         }

?>

You can see the code in action at http://codepad.org/01Z6rQ1o

Slip of Induction Machine : The Hidden Power

noreply@blogger.com (Unknown) — Sun, 22 Jan 2012 18:30:00 +0000

Ever wondered why slip is so important in induction machine?

(If you do not know, in case: slip is a measure of speed difference between stator and rotor magnetic field in induction machine.) When stator coil is energized in induction machine, it produces a magnetic field. If the energizing force i.e. voltage or current is rotating in nature, generated stator magnetic field is rotating in nature as well.

When this stator magnetic field starts rotating around rotor, it cuts the rotor coil (or the conductor bars embedded in rotor). Therefore, the rotor experiences a changing

Induction generator troubleshooting

noreply@blogger.com (Unknown) — Thu, 12 May 2011 17:59:00 +0000

Induction generators are widely used in diverse places ranging from shops to household. They are popular because of their low cost and simplicity. However, they can face frequent problems as Induction generators are not designed with securities conventional generators have.

In this post I am going to describe how a small but frequent problem in induction generators can be solved. This is my first approach to a series of posts about induction generator troubleshooting.

PROBLEM:

Generator is not producing electricity though it is rotating, or it is not producing its usual power, or it is not powering all equipments as it did couple of days ago.

SOLUTION:

Simply connect the induction generator to an existing conventional AC power source and run it as a motor for some times. This problem should be solved.

If you wonder what was the problem and how my solution will solve above mentioned problem, keep reading. I am going to describe it in next paragraph.

Induction generators are constructionally same as induction motors except for the fact that induction generators has a prime mover. This prime mover is run by diesel and in same cases, by other petroleum oils.
However, induction generators exploits the residual magnetism in the rotor and produce electricity. This residual magnetism is the source of electric energy produced in induction generator. Residual magnetism can be lost for a number of reason and I am not going to describe these reasons in this article. However, if residual magnetism is lost, no electricity will be produced even if the generator is running. To restore residual magnetism, just make the generator working as motor for a while. This will recreate the residual magnetism and everything will be fine. And you will make everything okay just after a little troubleshooting.

Regenerative braking of electrical machines

noreply@blogger.com (Unknown) — Thu, 06 May 2010 20:44:00 +0000

Regenerative braking is one type of electrical braking procedure. Normally energy is
dissipated in any braking procedure and in most cases, energy is lost as heat.Regenerative braking has been designed to utilize this energy,so the amount of energy lost as heat in other braking processes will be used for some productive purpose in this process.For example, in some areas with lot of mountains, a train is allowed to come down from top of mountain only when another is going up, so that one train can transfer its energy to another.Its charming, na!!

Fig:Regenerative braking

Look at the schematic. when we apply braking, stator is of course disconnected from main supply using switch set-4. But the rotor is rotating due to its inertia. In case of DC, synchronous and permanent magnet motor, rotor has distinct flux source. And in case of induction motor, rotor has residual magnetism. Therefore, virtually all machine has some sort of flux source on its rotor. When rotating due to inertia, this flux cuts

Dynamic or capacitive braking of electrical machine

noreply@blogger.com (Unknown) — Wed, 21 Apr 2010 06:47:00 +0000

Dynamic braking is a process in which kinetic energy of rotor is dissipated in external resistor as heat energy. It is an electrical braking process used in many industrial applications. Dynamic braking allows sudden stop of electrical motor without mechanical wear and tear.

In dynamic braking, stator has no supply at the time of braking. However, rotor is rotating due to inertia. In synchronous motor, rotor has a supply even when stator is disconnected from supply. In permanent magnet synchronous motor, rotor is a permanent magnet. In case of induction motor, rotor is very likely to have a residual magnetism. Therefore, in major types
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Electrical braking theory, reason of DC injection

noreply@blogger.com (Unknown) — Tue, 20 Apr 2010 10:45:00 +0000

Electrical braking is needed in many applications and used instead of mechanical braking. The advantage of electrical braking is virtually no wear and tear is experienced.

Electrical braking may be seen in modern cars, traction motor control, train services, alternators and in automotive industries.

Here I will discuss the basic principle, I will not elaborate in this post because I believe feeding everything in one pack will result in vomiting. So, for deeper understanding, read my blog time to time. Also, you may search my blog to find the later post. I will post them under the label "electrical braking". also, it is a good idea to subscribe via mail, if you want to get my articles in your inbox.

We understand if we can dissipate motors' kinetic energy quickly, we can implement a braking. So, all we need is to devise a way to dissipate kinetic energy rapidly.

The main theory of electrical braking is to use a DC (direct current) injection to provide magneto motive resistance to the running rotor. If a DC flux is provided to the rotor and rotor cuts through it, it eventually slows down because DC injection effectively produces a electrical (or more accurately, magnetic) resistance as described below.

Basic principle of induction machine(motor and generator)- simple description

noreply@blogger.com (Unknown) — Tue, 23 Mar 2010 19:05:00 +0000

An induction machine is the most simple electrical machine from constructional point of view, in most of the cases. It can be classified into motor and generator. In this post, I want to discuss the characteristic common to both of these. Detailed description of each will be available soon in other posts.

Induction machines work on induction principle, in other words it depends on Faraday's law of induction (i.e. when a conductor moves in a magnetic field, it gets some voltage(induced voltage). this voltage can set up current if construction permits and can set up its own magnetic field.). In this case it should be noted that moving in a magnetic field actually makes the magnetic flux changing to the moving conductor(actually seems to be changing, from the view point of one who is moving), and this changing magnetic field causes voltage and current to be induced on the moving body.

But if the magnetic filed is itself changing in nature, then it can

Finding N-th Fibonacci number and summation up to n-th fibonacci number in series using assembly language.

noreply@blogger.com (Unknown) — Sat, 28 Nov 2009 08:11:00 +0000

This code represents an example of finding Fibonacci number and sum of Fibonacci series up to n-th number. It is written in assembly language and simulated using emu8086 emulator. Though it is a general program, it cannot find more than 8-bit binary number, the reason is 8086 processor registers are 8-bit.

This is a general program for finding any number in Fibonacci series up to its limit and finding summation of two Fibonacci numbers written in assembly code and I checked this code with emu8086 emulator. Here it goes:

Code:

          
;   this program calculates the n-th Fibonacci number

;   and the sum of the fibonacci series upto n-th number

;the n-th number must be given in CX register

    CODE SEGMENT

    ASSUME CS:CODE,DS:CODE

    ORG 100H 

    ;S=F1+F2   // these 3 lines are algorithom

    ;F1=F2;

    ;F2=S;

    XOR AX,AX           ; clearing garbage value if any

    XOR BX,BX

Energy Saving Lamp- working principle and a potential problem

noreply@blogger.com (Unknown) — Fri, 06 Nov 2009 15:51:00 +0000

Energy saving lamps are operated at high frequency. They produce low real power consumption which actually mean reduced electricity bill. This is why Energy saving lamps are extensively popular. This may be seem attractive from user point of view, but may not be same for the provider.
This low real power (hence, low cost) consumption comes at the cost of of large reactive power consumption. This large reactive power demand may be easily ignored by user because they are not direct victim of this problem, but user as well as provider will suffer very much in the end.
Electricity providers only bill for real power, they do not collect money from user level for reactive power since, before the energy saving lamp, general user did not consume high reactive power. But they DO charge industrial customer at a different and higher rate than normal user because of consuming large reactive energy. That is why consumer and industrial feeder and bill rate are different.
The reason providers charge more for industrial application is higher reactive power consumption means
Read More>>

Assembly code for finding maximum and minimum number from an array and placing them in different arrays

noreply@blogger.com (Unknown) — Thu, 14 May 2009 04:35:00 +0000

Here is the assembly code for sorting maximum number and minimum number from an array. The code is written and tested in emu8086 software.

Sorting even and odd number and placing them in different arrays:

CODE SEGMENT
ASSUME CS:CODE,DS:CODE
ORG 100H
MOV CX,4H

TOP:

MOV AX,00H
MOV BX,00H
MOV BL,COUNT
MOV BH,00H
MOV AL,DATA[BX]
MOV DL,DATA[BX]
MOV STORE,DL
MOV AH,00H
MOV BL,02H
MOV BH,0H
DIV BL

JCXZ EXIT:

CMP AH,00H
JE EVEN:
JNE ODD:

EVEN:
MOV DH,0H
LEA SI,STORE_EVEN
ADD SI,COUNT_EVEN
MOV [SI],DL
INC COUNT_EVEN
JMP EXIT:

ODD:
MOV DH,00H
LEA SI,STORE_EVEN
ADD SI,COUNT_ODD
ADD SI,100H
MOV [SI],DL
INC COUNT_ODD
JMP EXIT:

EXIT:
INC COUNT
LOOP TOP:

HLT

;ORG 200H
;first semicolon should be omitted if the code is fed in MDA-8086 or MTS-86c
DATA DB 23H,34H,62H,65H
STORE DB ?
STORE_EVEN DB ?
STORE_ODD DB ?
COUNT DB 0H
COUNT_EVEN DW 0H
COUNT_ODD DW 0H

CODE ENDS
END

Necessary 100+ run commands for Windows

noreply@blogger.com (Unknown) — Fri, 20 Feb 2009 18:37:00 +0000

These commands are the usual shortcut way to do something by command prompt and applicable only in windows.

Commands:

1. Accessibility Controls - access.cpl
2. Accessibility Wizard - accwiz
3. Add Hardware Wizard - hdwwiz.cpl
4. Add/Remove Programs - appwiz.cpl
5. Administrative Tools - control admintools
6. Automatic Updates - wuaucpl.cpl
7. Bluetooth Transfer Wizard - fsquirt
8. Calculator - calc
9. Certificate Manager - certmgr.msc
10. Character Map - charmap
11. Check Disk Utility - chkdsk
12. Clipboard Viewer - clipbrd
13. Command Prompt - cmd
14. Component Services - dcomcnfg
15. Computer Management - compmgmt.msc
16. Control Panel - control
17. Date and Time Properties - timedate.cpl
18. DDE Shares - ddeshare
19. Device Manager - devmgmt.msc
20. Direct X Troubleshooter - dxdiag
21. Disk Cleanup Utility - cleanmgr
22. Disk Defragment - dfrg.msc
23. Disk Management - diskmgmt.msc
24. Disk Partition Manager - diskpart
25. Display Properties - control desktop
26. Display Properties - desk.cpl
27. Dr. Watson System Troubleshooting Utility - drwtsn32
28. Driver Verifier Utility - verifier
29. Event Viewer - eventvwr.msc
30. Files and Settings Transfer Tool - migwiz
31. File Signature Verification Tool - sigverif
32. Findfast - findfast.cpl
33. Firefox - firefox
34. Folders Properties - control folders
35. Fonts - control fonts
36. Fonts Folder - fonts
37. Free Cell Card Game - freecell
38. Game Controllers - joy.cpl
39. Group Policy Editor (for xp professional) - gpedit.msc
40. Hearts Card Game - mshearts
41. Help and Support - helpctr
42. HyperTerminal - hypertrm
43. Iexpress Wizard - iexpress
44. Indexing Service - ciadv.msc
45. Internet Connection Wizard - icwconn1
46. Internet Explorer - iexplore
47. Internet Properties - inetcpl.cpl
48. Keyboard Properties - control keyboard
49. Local Security Settings - secpol.msc
50. Local Users and Groups - lusrmgr.msc
51. Logs You Out Of Windows - logoff
52. Malicious Software Removal Tool - mrt
53. Microsoft Chat - winchat
54. Microsoft Movie Maker - moviemk
55. Microsoft Paint - mspaint
56. Microsoft Syncronization Tool - mobsync
57. Minesweeper Game - winmine
58. Mouse Properties - control mouse
59. Mouse Properties - main.cpl
60. Netmeeting - conf
61. Network Connections - control netconnections
62. Network Connections - ncpa.cpl
63. Network Setup Wizard - netsetup.cpl
64. Notepad - notepad
65. Object Packager - packager
66. ODBC Data Source Administrator - odbccp32.cpl
67. On Screen Keyboard - osk
68. Outlook Express - msimn
69. Paint - pbrush
70. Password Properties - password.cpl
71. Performance Monitor - perfmon.msc
72. Performance Monitor - perfmon
73. Phone and Modem Options - telephon.cpl
74. Phone Dialer - dialer
75. Pinball Game - pinball
76. Power Configuration - powercfg.cpl
77. Printers and Faxes - control printers
78. Printers Folder - printers
79. Regional Settings - intl.cpl
80. Registry Editor - regedit
81. Registry Editor - regedit32
82. Remote Access Phonebook - rasphone
83. Remote Desktop - mstsc
84. Removable Storage - ntmsmgr.msc
85. Removable Storage Operator Requests - ntmsoprq.msc
86. Resultant Set of Policy (for xp professional) - rsop.msc
87. Scanners and Cameras - sticpl.cpl
88. Scheduled Tasks - control schedtasks
89. Security Center - wscui.cpl
90. Services - services.msc
91. Shared Folders - fsmgmt.msc
92. Shuts Down Windows - shutdown
93. Sounds and Audio - mmsys.cpl
94. Spider Solitare Card Game - spider
95. SQL Client Configuration - cliconfg
96. System Configuration Editor - sysedit
97. System Configuration Utility - msconfig
98. System Information - msinfo32
99. System Properties - sysdm.cpl
100. Task Manager - taskmgr
101. TCP Tester - tcptest
102. Telnet Client - telnet
103. User Account Management - nusrmgr.cpl
104. Utility Manager - utilman
105. Windows Address Book - wab
106. Windows Address Book Import Utility - wabmig
107. Windows Explorer - explorer
108. Windows Firewall - firewall.cpl
109. Windows Magnifier - magnify
110. Windows Management Infrastructure - wmimgmt.msc
111. Windows Media Player - wmplayer
112. Windows Messenger - msmsgs
113. Windows System Security Tool - syskey
114. Windows Update Launches - wupdmgr
115. Windows Version - winver
116. Wordpad - write

Solution manuals of Electronics books

noreply@blogger.com (Unknown) — Tue, 10 Feb 2009 18:57:00 +0000

Electronic Devices and Amplifier Circuits with MATLAB Applications

Devid Bell Electronic books solution

Solutions Manual for System Dynamics 3rd Ed
By Katsuhiko Ogata

Solutions Manual for: Materials Science and Engineering An Introduction 6E
By William D. Callister Jr

Engineering Circuit Analysis 6Ed by Hayt (Solutions Manual)
Password if required is: http://www.elektrotekno.com/

Teach Yourself Electricity And Electronics 3Rd
--by Gibilisco

Integrated circuits
by Millman and Halkias

Practical electronics handbook

The art of electronics

Microelectronic circuits
--by Sedra and smith

Electrical Machinery Fundamentals
--by Stephen J.Chapman

Electrical Machinery Fundamentals Corrections
--by Stephen J.Chapman

Fundamentals of Power Electronics