Education

We gave you Science lessons and also IT lessons to refer to. You can use this category only for education. (physical science, chemistry, computer science, mathematics, biological science) education of phobia.tech.

9v battery and led circuit-Simple LED Circuit

I know you are new to the electronic field. Also, I guest you burn a few LEDs at this movement (haha). Do you want to know why? Okay then, stick to my article. I will explain how to connect LEDs correctly and also what is the reasons you burn your LEDs. (tags: Simple LED Circuit, 9v battery and led circuit)

First of all, we connect the circuit now, after that you can read what is the theory behind all these things as your interest. All of these theories are explained at the end part of this article. Okay let’s go to the article but I recommend reading the theory part first and after reading these things.


What do we need?

simple led circuit components 9v battery 3v battery 1.5v battery LEDs resistors wires
  • LEDs
    • any colour of the LED
  • Resistors
    • 10, 390, 470, 560 ohms
  • Battery
    • 3v, 6v, 9v, or 12v
  • wires
    • normal circuit wires

We have two terminals in LED, a longer one for the positive terminal and a shorter one for the negative terminal.


Simple led circuit: 1.5v battery

Do you have a 1.5 V battery? okay then, find another 1.5 V battery. Because LED needs a minimum of 1.8 V to operate, therefore, you can’t operate a LED using a single 1.5 V battery. (1.5 < 1.8)


Simple led circuit: 3v battery with 10 ohms resistor

3v battery and led circuit

Okay, here is the simple 3 V LED circuit diagram and the Example circuit that I made for you. First, you can find 3 V battery or get two 1.5 V battery and connect them with serial way like the diagram and also use 10 ohms resistor to protect the LED but it was not necessary. always remember that the longest pin in LED is for positive (+) and a shorter one for negative (+). I hope you can understand this and also please read the Theory part of this article which is in the end part of this article for more information.


Simple led circuit: 6v battery with 390 ohms resistor

LED, 390 ohms resistor 6 v diagram

Here you can see the circuit diagram and also you can use four 1.5 v batteries or one 6 v battery with this circuit. The 390 ohms resistor is the most important component in this circuit and also if you forget to connect this to the circuit then surely your LED will burn. You have to read the final heading (Theory) of this article to get more knowledge. (tags: Simple LED Circuit)


9v battery and LED circuit with 470 ohms resistor

9v battery and led with 470 ohms resistor diagram

Here are my 9v battery and led circuit with a 470 ohms resistor. Also, You can see positive and (+) and negative (-) terminals are marked in the 9V Battery. Also now you know the positive (+) terminal is the longest pin and negative (-) terminal is the shorter pin in the LED. For more information, continue reading this article and also you can get all the knowledge about these LEDs, Resistors, and Batteries. (tags: Simple LED Circuit, 9v battery and led circuit)


how to connect led lights to car battery (12 v battery with 560 ohms)

LED with 12v diagram

Here you can see, this diagram shows how to connect a LED with a Car Battery (12). You have to use 560 ohms resistor to connect with this circuit and also you can refer more with this article. (Read the theory part of this article which is in the last) (tags: Simple LED Circuit, 9v battery and led circuit)


THEORY

Hi there, Welcome to the boring part of this article and also Please refer to this part completely I’m sure you will get something from here. Don’t forget to comment on this article and also give your idea and point out the topics that I missed here. 🙂

I hope you have a battery and some LEDs. When you connect your LED to the battery directly it will destroy immediately. Do you know normally LEDs are working in the 1.8 – 3.8 V voltage range? However, the range varies with the color of the LED. (tags: Simple LED Circuit)

The following chart will help you to understand the LEDs operating voltage.

Color of LEDVoltage (V)Current (mA)
White3.2 – 3.820 – 30
Warm White3.2 – 3.820 – 30
Blue3.2 – 3.820 – 30
Red1.8 – 2.220 – 30
Green3.2 – 3.820 – 30
Yellow1.8 – 2.220 – 30
Orange1.8 – 2.220 – 30
Pink3.2 – 3.820 – 30
UV3.2 – 3.820 – 30
table 01 (9v battery and led circuit)

Okay, now take your battery and check it’s the voltage. Also It has been marked on the battery. It should be one of the following values: 1.5V, 3V, 6V, and 12V. (tags: Simple LED Circuit)

LED with 1.5v battery

Let’s see what happens when you connect the LED directly with the 1.5V battery. Now you know LEDs operating voltage is between 1.8 and 3.8V. but when you supply 1.5V to the LED, which is lower than the minimum operating voltage of the LED. Also If the battery has 1.5V, you cannot get the perfect brightness from it. Then you realize that you can’t emit light from
LED using a 1.5V battery.

LED with 3v battery

Now let us see what happens when you connect the LED directly with a 3V battery. 3V is a value, which is in the operating voltage range of LED. Now again look at the “table 01” that I mentioned above. According to that, you can see white, blue, green, pink, UV needs a minimum of 3.2V to get maximum brightness. Then you can understand that you cannot operate these color LEDs using a 3V battery. However, according to “table 01” red, yellow and orange LEDs have 2.2V of maximum operating voltage. But 3V > 2.2V. Anyhow, we can see led can emit brighter light without burning when they connect into 3V. But it can shorter their life. Also To avoid this problem we can use resistors. (tags: Simple LED Circuit)

LED with 6v, 9v, and 12v battery

Finally, let’s see what happen when we connect LED directly with 6V, 9V or 12V battery. I think now you have all the knowledge to imagine this situation. These voltages are higher than the maximum operating voltage (6V/9V/12V > 3.8V). Also, If we connect LED directly with these batteries immediately it will burn. To avoid this you need to use resistors. (tags: Simple LED Circuit)

Resistor???

Now let’s see what is the resistor. The resistor is a very important component in electronics. The resistor is used to block the current through a circuit and then reduce the voltage of the component that we need. Also, Resistors can connect series or parallel with the circuit according to our requirements. When it comes to the LED, resistors are connected series with LEDs. Also, The value of the resistor can be calculated using the color code. (tags: Simple LED Circuit)

Let’s see about the circuits

You can scroll up and see the relevant circuit diagram that I provided in with the related title.

3V basic LED circuit

Let’s see how we can connect LED with a 3-volt battery. Also If you are using Red, Yellow or Orange color LEDs, you need to connect it through 10 ohms resistor.

6V basic LED circuit

If you are using red, yellow or orange color LEDs, then connect the LED through 210Ω resistor. Also If the LED has a different color (except red, yellow and orange) we use 140Ω resistor series with the LED.

9V basic LED circuit

If you are using red, yellow or orange color LEDs, also you need to use a 360Ω resistor with LED. Or if you use a different color than above use 290Ω resistor to protect your LED.

12V basic LED circuit

If the LED has red, yellow or orange use 510Ω resistor series with the LED and also if LED has different colors use 440Ω resistor. (tags: Simple LED Circuit, 9v battery and led circuit)


Okay, I think you get something from this article. now you can give feedback for my article. Click here to read more article in my site and also you can refer more here. Thank you…

What is an Arduino?

Arduino is a simple programmable Circuit board, just like a small computer. You can program this to input data, process data and also get output from it or perform some action as output. Arduino is an open hardware development device, therefore you can program and create whatever you want it’s free. and We can make simple color light Patterns to complex Robots using this Arduino.

Arduino board

This is my Arduino nano board, And also you can buy different models of Arduinos. Like Arduino Mega, UNO, nano, pro mini, also, etc. But I recommend using UNO or Nano as a beginner.


What are the components of this board?

atmel mega 328p IC arduino board

This is the main part of the Arduino board, The Atmel chip. this is nano and also it has Atmel mega 328p chip as the main IC. You can see Different kinds of Atmel chips in different Arduino boards. Let’s see about that.

Atmel chip (Processor)Arduino BoardMemory (RAM)Digital Pins (I/O)Analog Pins (I/O)
ATmega328
(16 MHz)
Arduino Uno, nano, pro mini,…2 KB SRAM, 32 KB flash146 (6/0)
AT91SAM3X8E
(84 MHz)
Arduino Due96 KB SRAM, 512 KB flash5414 (12/2)
ATmega2560
(16 MHz)
Arduino Mega8 KB SRAM, 256 KB flash5416 (16/0)
ATmega32u4
(16 MHz)
Arduino Leonardo2.5 KB SRAM, 32 KB flash2012 (12/0)
Table of Arduino board types

Other components

components of arduino board

Let’s see about the components in this Arduino nano board. Also, This is the front side of the circuit. You can see here,

  1. Oscillator
    • This Oscillator generates 16 MHz frequency, Also That frequency helps to operate this Atmel Mega 328P chip. In different Atmel chips need a different value of frequencies. Also, All the values are shown in the table.
  2. Reset Button
    • This is a simple push-button, also You can press this to restart the program in this board.
  3. USB Mini-B Port
    • This port is used to connect this Arduino with your PC. also You can refer more to Wikipedia.
  4. LRD Indicators
    • Here you can see 4 lights, Also It indicates some information to the user. First and also Second lights indicate the serial communication of this Arduino board. Also, The third light indicates the power connection of the board. Forth light for the Testing purpose and also we can use it to get output from this board.

Also, Let’s see back side of the nano board,

3.3v regulator IC, serial communication IC
  1. Serial Communication IC
    • Atmel chip only can operate with serial signals, therefore This IC (CH340G) helps Atmel chip to Communicate with the PC. It converts USB data signals to serial data signals.
  2. 3.3V Regulator
    • This Arduino operates with 5V voltage. Sometimes we need 3.3V to connect some components with this board, In that case, we can get that 3.3V output from this regulator.

Arduino Nano pin diagram

arduino pin set, analog pins, digital pins, ground pins, reset pins, 5v pin, 3.3 v pin, 3.3v
  1. Digital Pins
    • We have 12 digital pins in nano. Also, we can use these pins to connect digital components. It can only operate with two-stages, in high stage pin has +5V voltage and also low stage pin has 0V voltage which is equal to the ground pin.
  2. Analog Pins
    • Here in Nano has 8 analog pins. Also, we can get analog readings through these pins. Also, It can vary between 0V to 5V.
  3. Reset Pins
    • There are two reset pins we have in nano. Also If we supply this pin to +5V voltage, the board will consider the same action as we press the reset button on the board. Also, It will restart the program in the Arduino.
  4. Ground Pins
    • Also, This is the 0V pin. We can use this pin when the components are connecting to this board and also we supply external power for this board.
  5. 5V Pin
    • Also Using this pin we can get +5V dc voltage from this board.
  6. 3.3V Pin
    • This pin is using the 3.3V regulator, Also we can get +3.3V output from this pin.

What is the difference between Arduino Nano and UNO?

What is the difference between Nano and UNO?

You can see here, when we compare these two UNO board is larger than Nano. But components in there are same. Also, Thay all are work with the same concept.



Also, I think now you are ready to program this board. You can see how to work with this in our next article. you can read more articles in our phobia.tech site and also you can refer more from here.

Rocket Motion – Variable Mass Problem (Mechanical Physics)

rocket motion

Rocket Motion – Variable Mass Problem (Mechanical Physics Part 2)

  • v is upward vertical rocket velocity related to Stationary Earth.
  • vo is the initial rocket upward velocity of propellant Fuel relative to stationary earth. also initial exhaust velocity relative to stationary earth.
  • D is downward atmospheric force, this is neglect this time for simplicity.
  • T – Thrust force applying Newton’s 3rd Law.
  • u – exhaust velocity relative to the rocket.
  • Fext – Net external force expended in accelerating rocket and also variable mass propellant fuel.

Defining Ideal Rocket

  • There is no twisting or turning moment force acting on the rocket.
  • The thrust T acts precisely at the rocket’s center of mass.
  • The rocket and it’s propellent fuel mass solely involved in upward translational rectilinear motion.
  • There is a realistic assumption of constant fuel burn rate implying constant thrust T.
  • The gravity acceleration is assumed to be constant.

In the beginning part of the analysis, the rocket does not escape the earth’s gravity field.

Rocket Motion
Rocket Motion
Rocket Motion

Derivation of Rocket Equation

Rocket equation
Rocket equation
rocket equation

Generalized Equation (Rocket Motion – Variable Mass Problem)

[katex]{ F }_{ a }\quad +\quad T\quad -\quad mg\quad =\quad \frac { md(v) }{ dt }[/katex]

This generalizes the rocket equation considers rocket weight by factoring out external gravity force of rocket and fuel weight from Fa but keeping drag D as part of Fa .

Rocket Motion – Variable Mass Problem (Mechanical Physics Part 2)


Rocket Equation 2 (Rocket Motion – Variable Mass Problem)

[katex]\frac { dv }{ dt } \quad =\quad \frac { T }{ m } \quad -\quad g[/katex]

This equation is really / corollary to the above equation.

  • g is constant gravitational field acting upon rocket and propellant masses and also thrust force T.
  • m – Total mass including propellant fuel.

[katex]T\quad =\quad \frac { ud(m) }{ dt }[/katex], thrust excreted by exhaust velocity of propellent.

Rocket equation 2

g is constant gravitation field then,

Since it vaeies inversly thrue rocket length.

Rocket equation
  • vo – Initial rocket velocity.
  • vbo – Burn out velocity, rocket velocity moment at complete.
  • dv = vbo – vo, maximum burn out velocity.
  • u = – ( v – vo ), effective exposed velocity.

Initial total rocket and propellant

Rocket Motion rocket equation 2
rocket equation

Rocket Equation 3 (Rocket Motion – Variable Mass Problem)

Rocket equation
rocket calculation

Also, this gives maximum rocket velocity at time t. Rocket Motion – Variable Mass Problem (Mechanical Physics Part 2)


Rocket Equation 4 (Rocket Motion – Variable Mass Problem)

Rocket equation 4

Propellent mass function,

rocket  equation

Which is the fraction of initial mass that is reaction mass.

rocket equation 4

Thrust to weight ratio

rocket equation

In other words the specific impulse can be defined as the ratio of the thrust produce to the rate at which the rocket consium its fuel.

Relationship between total impulse and specific impulse

relationship between total impulse and specific impulse

Determination of burn out time

Determination of burn out time
Determination of burn out time
Determination of burn out time
Determination of burn out time

Rocket Equation 5

Rocket equation 5

Question: (Rocket Motion – Variable Mass Problem (Mechanical Physics Part 2))

Consider a rocket moving in a space suppose that 2.1×106 kg of fuel a consiume during a burn last in 1.5×102 s. Give that there is a constant force on the rocket of 3.4×107 N. During this burn calculate the velocity of the exposting fuel. Hence calculate the increasing speed resulting some their burn. If the initial mass is 2.8×106 kg.

What is the initial vertical acceleration that can be important to this rocket when it is launched from the earth?

Answers,

………….


Rocket Motion – Variable Mass Problem (Mechanical Physics Part 2)

You can refer to “How to Build a Tesla Generator” from HERE, Also refer to the wiki.

Introduction To Visual Basic Application Development (Practical)


CHAPTER 02


Introduction To Visual Basic Application Development

Visual Basic : Introduction
  • “Visual” refers to the method used to create what the user sees (Graphical User interface).
  • “Basic” refers to the BASIC (Beginners All-Purpose Symbolic Instruction Code) programming language.
  • It is a high-level programming language that evolved from the earlier DOS version called BASIC.
  • Visual Basic originally created to make it easier to write programs for the Windows computer operating system.
  • One of the major reasons why Visual Basic has been so successful is that it includes everything that is necessary to write programs forWindows.
  • For many years, Microsoft Visual Basic has been the world’s most popular programming language.
  • From its very beginning, Visual Basic has brought unmatched flexibility and ease of programming to theWindows platform.
  • In its previous six versions, Visual Basic evolved into an extremely powerful development tool that was equally at home in business, academia, engineering, or everywhere else in which windows applications were being created.
  • The latest version of Visual Basic, called Visual basic .NET, is the most significant evolutionary change yet in the language. (Introduction To Visual Basic)

General Features Of The Visual Basic

  • GUI:- Graphical User Interface is there to represent the program objects and also the techniques.
  • Modularization:- Good program practice to modularize program.
  • Object-Oriented:- Creating objects while writing programs.
  • Debugging:- Runtime debugger helps to find and also fix the bugs/ errors at runtime.
  • Data Access aspect:- Users can able to create a database and also retrieve data at runtime.

Introduction to Visual Studio Express 2012

Introduction to Visual Studio Express 2012
  • Visual Basic Express 2012 is almost similar to Visual Basic Express 2010 & 2008, but it has added many new features.
  • Visual Basic Express 2012 no more comes as a stand-alone program, it is now integrating with other Microsoft Programming languages C# and also C++ in a package called visual Studio 2012.

(Introduction To Visual Basic Application Development)


.NET Framework Architecture

.NET Framework Architecture
  • The .NET Framework is Microsoft’s new platform for the development and implementation of applications program.
  • Simply, .NET is a new framework for developing web-based and also windows-based applications within the Microsoft environment.
  • Microsoft and other publishers of development tools realized that they could write the code needed to perform a variety of commonly needed tasks and also make this functionality available to the programmer in an easy-to-use form.
  • So, the framework did all the work behind the scenes, serving as an interface between the program and the operating system.
  • Two main parts of the .NET framework are:
    • Common Language Runtime.
    • .NET framework classes/ libraries.

Common Language Runtime (CLR)

Common Language Run time (CLR)

CLR is considering as the heart of .NET. It also provides a “runtime environment” for the execution of code written in any .NET Language.

  • Features :
    • Common type system
    • Common metadata
    • Intermediate Language (IL) to native code compilers
    • Code execution and security
  • Additional services :
    • Memory Management
    • Thread Management
    • Garbage Handling
    • Exception Handling
  • Much of the functionality available to the VB .NET programmer is provided by the .NET Class Framework.
  • This is a rich set of classes, interfaces, and also structures that provides support for data storage, access to system services, input/output, security and a whole host of other things that the programmer needs.
  • The class framework is arranged hierarchically using the concept of namespaces.
  • A namespace is nothing more than an identifier that is used to group related items together.
  • The root namespace contains classes for all of the base data types (Integer, Char, Array and so on) as well as for the Object type that is the base for all .NET components.
  • Applications that can make use of .net class library:
    • Windows applications
    • Console applications
    • Web applications
    • XML web applications/services
    • Windows services

Elements of a Visual Basic Application

From a programming viewpoint, Visual Basic is an object-oriented that consists of two fundamental parts.

A visual part and a language part

  • The visual part of the language consists of a set of objects, while the language part consists of a high-level procedural programming language.
  • These two elements of the language are using together to create applications.
  • Thus, for our purposes, we can express the elements of a visual basic application as:
A visual part and a language part

(Introduction To Visual Basic Application Development)


The Visual Element

  • From a user’s standpoint, the visual part of an application is provided within a window. This is the graphical interface that allows the user to see the input and also output provided by the application.
  • This user interfaces referred to as the graphical user interface (GUI).
  • From a programmer’s perspective, the GUI is constructed by placing a set of visual objects on a blank window, or form, when the program is being developed.
The Visual Element
  • The programmer can place various objects on this form, which is itself a Visual Basic object.
  • When an application is run, the form becomes a window that provides the background for the various objects placed on the form by the programmer.
  • The standard object Tool-box contains the objects we will use in constructing each graphical user interface.
The Visual Element (contd…)

Fundamental Object Types and their Uses

Fundamental Object Types and their Uses Introduction To Visual Basic Application Development

Creating a Visual Basic program

  • To create a Visual basic program you will need the following three windows:
    • Toolbox window for selecting objects
    • Form window for placing objects
    • The properties window for altering an object’s properties

Additionally, the Solution Explorer window should be visible when you begin.

  • Once the design windows are visible, creating a Visual Basic application requires the following three steps:
    • Create the graphical user interface
    • Set the properties of each object on the interface
    • Write the code

Setting an Object’s Properties

  • All objects on a form have properties, which define where on the form the object will appear. The color of the object, its size, and also various other attributes.
  • The properties window allows properties to be listed in alphabetic order, by property name or by property category, By default, also the properties are sorted by category.
  • The two columns within the properties window are where individual object properties are identified.
    • The column on the left is the properties list, which provides the names of the properties of the object also named in the object box.
    • The column to the right is the settings list, which provides the current value assigned to the property also on the left.
    • The currently selected property is the one that is highlighted.

(Introduction To Visual Basic Application Development)


The Properties Window

Introduction To Visual Basic Application Development

Basic Concepts in Introduction To Visual Basic Application Development

The Name Property:

  • The names that are allowed for all objects are also used to name other elements in the Visual Basic programming language and are collectively referred to as identifiers. Identifiers can be made up of any combination of letters, digits or underscores( _ ) selected according to the following rules:
    1. The first character of an identifier must be a letter.
    2. Only letters, digits or underscores may follow the initial letter (Blank spaces, special characters, and also punctuation marks are not allowed)
    3. An identifier can be no longer than 1016 characters
    4. An identifier cannot be a keyword.

Running an Application:

  • At any time during program development, you can run your program using one of the following three methods:
    1. Select the Debug Menu and Click Start
    2. Press the F5 function key
    3. Use the hotkey Alt + D, then press the S key.

Saving a Project:

  • Click the File menu and then click Save All.
    • At this point, all the forms, code modules, and ancillary files will be saved in a folder. Also, the name of the folder will be the project name.

OR

  • Click ” SaveAll ” icon in the Standard Toolbar.
    • Also, It recommends you save your solution to prevent accidental loss of work.

Adding an Event Procedure

  • In a well-designed program, each procedure will consist of a set of instructions necessary to complete and also a well-defined task.
  • Although a procedure that is executed when an event occurs is referred to as an event procedure or event handler.
  • The following slide illustrated The general structure of an event procedure:
Introduction To Visual Basic Application Development
Introduction To Visual Basic Application Development

Write two simple event procedures for action while a form loading in the execution of VB .NET

Example 1:

execution of VB .NET

Example 2:

execution of VB .NET
  • The first line of a procedure is always and also a header line.
  • A header line begins with the optional keyword Private and must contain the keyword Sub (which derives from the word Subprogram), the name of the procedure and also a set of parentheses.
  • For event procedures, the name consists of
    • an object identification,
    • an optional underscore character ( _ ),
    • a valid event for the object,
    • the parameters in parentheses,
    • the keyword Handles followed by the object identification,
    • an underscore character &
    • a valid event.
  • Event procedure templates need not be manually typed because they are automatically provided in the visual Basic Code window.
  • Before activating the code window, we need to decide what Visual Basic statements will be included in the body of our event procedure. (Introduction To Visual Basic Application Development)

Find some additional features of VB .NET compared to VB

For the Visual Application Development (Theory) lesson, click here. also, you can refer more in here.

Visual Application Development (Theory)

Learning Objectives in Visual Application Development

  • To provide an introduction to the fundamentals of programming.
  • Enable students to build simple and also graphical applications to address the problems they face in academic and business settings.
  • Enhance analysis, design, development, troubleshooting, and critical thinking skills.

(Visual Application Development)


CHAPTER 01


Software Processes

  • When we provide a service or create a product we always follow a sequence of steps to accomplish a set of tasks.
  • We can think of a series of structured activities as a process.
  • Any process that has the following characteristics,
    • prescribes all of the major activities.
    • uses resources and produces intermediate and final products.
    • organized to include sub-processes & activities in a sequence.
    • Constrains or control may apply to activities (Budget control and also the availability of resources).
  • When the process involves the building of some product we refer to the process as a life cycle. (Visual Application Development)

Introduction to SDLC

  • The Software Development Life Cycle is the process, involving multiple stages also used to convert a management need into an application system, which is custom developed or purchased, or is a combination of both. (Visual Application Development)
  • SDLC is . . .
    • A model of a detailed plan on how to create, develop, implement and also deliver software.
    • A complete plan outlining how the software will be born and also raised and turned over to its eventual user.

Basic Pattern of General Life Cycle Models

Basic Pattern of General Life Cycle Models
Basic Pattern of General Life Cycle Models

Each phase produces output (deliverables) that will be the input to the next phase. So, a software process model is an abstract representation of a process. (Visual Application Development)


Types of SDLC

Sequential Development
Sequential Development
Iterative Development
Iterative Development

Sequential Development

Sequential Development
  • A development strategy wherein a strict set of development phases or stages followed in sequential or linear order.
  • Only when one phase or stage is completed can development move on to the succeeding phase or stage.
  • Also Sometimes referred to as a classical or traditional method of software development.

(Visual Application Development)


Iterative Development

Iterative Development
  • Iterative development is a strategy for scheduling a certain amount of time for rework or revisions in order to improve the quality of the different parts of the system being built.
  • It doesn’t start with a full specification of requirements.
  • Instead, development begins by specifying and implementing just part of the software, which can review in order to identify further requirements.

(Visual Application Development)


Flowchart for Iterative Development

Flowchart for Iterative Development

SDLC Models

  • Waterfall Model
  • Spiral Model
  • Rapid Application Development
  • V Model
  • Agile Model

Waterfall Model

Waterfall Model
  • Executed the Phases in sequential order
  • Completed Each phase before proceeding to the next.
  • Customer Can’t see Software until the end of the project.
  • It provides a structured approach.

Advantages of the Waterfall Model

  • Relatively simple to understand.
  • Give importance to documentation.
  • Each phase of development proceeds sequentially.
  • Allows managerial control where a schedule with deadlines is set for each stage of development.
  • Helps in controlling schedules, budgets, and also documentation.
  • It provides a structured approach.
  • Generally suited for stable projects.

Disadvantages of Waterfall Model

  • Requirements need to be specified before the development proceeds.
  • Can’t make the changes in requirements in later phases of the waterfall model. This implies that once the software enters the testing phase, it becomes difficult to incorporate changes at such a late phase.
  • No user involvement and working version of the software is available when the software is being developed.
  • It does not involve risk management.
  • Assumes that requirements are stable and are frozen across the project span.

(Visual Application Development)


Spiral Model

Spiral Model
Spiral Model
Spiral Model
  • The iterative model with an emphasis on risk analysis.
  • Aims to combine advantages of top-down and also bottom-up concepts.
  • Good for large and also mission-critical projects.
  • But success highly depends on risk analysis and can be costly.

Phases of the Spiral Model

  1. : Determine objectives and also constraints.
  2. : Assessed the risks and also the activities put in place to reduce the key risks.
  3. : Also Chose the development model for the system.
  4. : Reviewed the Project and also planned the next phase of the spiral.

Problems Addressed…

Problems Addressed
  • With conventional methods,
    • There is a long delay before the customer gets to see any results.
    • Development can take so long that the customer’s business has fundamentally changed by the time the system is ready for use.
    • It is obvious that there is nothing until 100% of the process is finished.

(Visual Application Development)


Rapid Application Development (RAD)

“A software development process that allows usable systems to be built in as little as 60-90 days and also often with some compromises”

“A software development methodology that uses minimal planning in favor of rapid prototyping.”

(Visual Application Development)

RAD Phases

RAD Phases
RAD Phases

A RAD Environment

A RAD Environment

Visual Application Development

For the Visual Application Development (practical) lesson, click here. also, you can refer more theory in here.