LIGHT EMITTING DIODE

What is Light Emitting Diode(LED)?
A Light Emitting Diode(LED) is a semi conductor device that emits visible light when current flows through it. LED is the source of light which converts electrical energy to Light Energy. PN junction diode emits Monochromatic Light , occurring at single wave length.

Light Emitting Diodes are especially PN junction Diodes operated in Forward Bias.

Early LED's can produce Red Light only. But modern LED's can produce different colors including Red,Green,Blue(RGB).We can produce white light also with the help of advancement in the technology. LED requires 1.5-4 V and 10mA to power on. One needs to use a series resistor to prevent overloading.

LED CIRCUIT

In electronics , the basic LED circuit is an electric circuit used to power a Light Emitting Diode(LED).
This simplest circuit consists of a voltage source and a series resistance and an LED. Optionally a switch can be used to open or close the circuit. This switch may be replaced with another component or circuit to from a continuity tester.

HOW DOES LED WORK?

Each time an electron recombines with a positive charge, Electric potential energy is converted into electromagnetic energy. For each recombination of negative and positive charge a quantum of electromagnetic energy is emitted in the form of light with a frequency characteristics of the semi conductor material.
 
 Here are the some of the Advantages of LED over incandescent and fluorescent illuminating devices.
 1.Low Power requirement: Most of the LED's can be operated with Battery supplies.
 2.High Efficiency: Most of the power supplied to the LED has been converted into radiation with    minimum heat production.
3.Long Life: LED's have long life span (often more than 100,000 hours) .If the LED is properly designed then it can be function for decades.

APPLICATIONS :

1.LED's are used in Digital Clocks and display purpose in many applications.
2.They are used in Traffic Controlled systems, Indicator lights and remote controlled devices.
3.As the LED's have long life span they can replace traditional light bulbs in several areas. 

KNOW ABOUT PHOTO DIODE

DIODES

What is a Diode?
Diode is an electronic component with active electrodes ,which allows the flow of current only in one direction.The two electrodes of the diode are Anode(+) and cathode(-).  Diodes are made up of semiconductor materials like silicon, Germanium.

The fundamental property of the diode is to allow the flow of current in only one direction.

How PN junction diode is formed?

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PN junction diode is made from a combination of 2 extrinsic semiconductors such as P-type semiconductor and N-type semiconductor. P-type semiconductor is formed when intrinsic semiconductor is doped with trivalent elements such as Al, Ga and Indium. N-type semiconductor is formed when intrinsic semiconductor is doped with pentavalent impurities such as Phosphorous, Arsenic or Antimony.
Here the joint between P-type and N-type semiconductors is called as PN junction. At the PN junction electrons from the N-type semiconductor will be attracted to the holes of P-type semiconductor. As a result the electrons and holes at the PN junction will disappear forming a layer called "depletion layer". At the same time P-type semiconductor become more negative and N-type semiconductor will become more positive. This results in a potential difference across PN junction.
This potential difference is called as 'Junction voltage or Barrier Voltage'. This junction voltage will prevents the charge carriers from flowing across the depletion region.
Diode can be used in both Forward Bias and Reverse Bias. The polarity of the applied voltage which allows the flow of current is known as 'Forward Bias'. The polarity of the applied voltage which doesn't allows the flow of current to flow is called as 'Reverse Bias'.

Forward Bias:

In Forward Bias positive terminal of the Battery is connected to the P-type material and negative terminal of the Battery is connected to the N-type material of the PN junction Diode. In forward Bias the diode acts as short circuit and start conducting , so that current will pass through Diode .But the diode starts conducting After the 'Cut in voltage or Break over voltage'.Cut in voltage is defined as the minimum voltage below which current is negligible above which the diode starts conducting.Cut in voltage for si is 0.7v and Germanium is 0.3v . 

Reverse Bias:

In Reverse Bias positive terminal of the Battery is connected to the N-type material and negative terminal of the Battery is connected to the p-type material of the PN junction Diode.In reverse Bias the diode acts as open circuit and no current will flow through the diode. 

V-I CHARACTERISTICS OF PN JUNCTION DIODE

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Diodes are mainly used as Rectifiers, Signal limiters, Voltage Regulators ,Switches ,Signal Modulators , Signal Demodulators,Clippers,Clampers.

TYPES OF DIODES: 

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1.LIGHT EMITTING DIODE

2.PHOTO DIODE
  

And also see : TRANSISTORS

RESISTORS

A Resistor is an Electrical component which limits or regulates the flow of current.The Resistor's ability to reduce the current is known as 'Resistance'. Resistance is measures in ohms(Ω).

Resistance value is stable over a wide range of environmental conditions.

 We can also say that The resistance 'R' of a resistor is equal to the resistivity 'ρ'  times the resistor's length 'l' divided by the resistor's cross sectional area 'A'.
 

The term Resistor is derived from ohm’s law .Ohm's Law: 

According to ohm’s law Current is directly proportional to voltage.
V∝ I
V=IR , and R=V/I
Here 'R' is the resistance which opposes the flow of current.
Carbon or metal film resistors are the most commonly used resistors.

How to find resistance of a Resistor?

Each Resistor has different type of colors on it .By make use of these colors we can calculate the resistance value of a Resistor.There are 3 types of color codes for a resistor:
1)4 band Resistor
2)5 band Resistor
3)6 band Resistor

Color code for  4 Band Resistor:

In a Four band Resistor 4 Bands make the resistance value.
 Band 1-digit
Band 2-digit
Band 3-multiplier
Band 4- tolerance

The first two bands will take the digit values according to

Black

0

Brown

1

Red

2

Orange

3

Yellow

4

Green

5

Blue

6

Violet

7

Gray

8

White

9

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The 3rd band(multiplier) is color coded as follows:
black – x1        brown – x10       red – x100
orange – x1K   yellow – x10K   green – x100K
blue – x1M      violet – x10M    grey – x100M
white – x1G      gold – .1           silver – .01

The color code for tolerance is as follows:
brown – 1% red – 2% orange – 3%
yellow – 4% green – .5% blue – .25%
violet – .1% gray – .05% gold – 5%
silver – 10%If the value of resistance is 470 ohm and the 4th band of the resistor was silver(10%) ,then the value range would be resistance value+/- 10% = 460 to 480.

Here in the above example The 4 bands of the resistor are
Brown, Black, Red, Green
(Brown=1),(Black=0),(Red=2)
Tolerance(Green) = ±0.5%
Resistance value=10 x 100 = 1k ohm

Color code for  5 Band Resistor:

In a Five band Resistor 5 Bands make the resistance value.
Band 1-digit
Band 2-digit
Band 3-digit
Band 4-multiplier
Band 5- tolerance

                                               
Here the 5 bands of the resistor are
Red,Red,Black,Red,Gold
red=2,Red=2,Black=0,red=100
Tolerance(gold)=5%                                         Resistance value=220X100=22K ohm

Color code for  6 Band Resistor:

In a Six band Resistor 6 Bands make the resistance value.
Band 1-digit
Band 2-digit
Band 3-digit
Band 4-multiplier
Band 5-tolerance
Band 6-temperature coefficient

Here we have 6 bands of resistor are  Yellow,Brown,Red,Orange,Brown,Violet Resistance=412X1000=412k Ohm

Also Know about: Capacitors

ARDUINO

 Hi friends. If you are crazy about electronics and want to do projects, then ARDUINO is the right choice for you.

What is Arduino?

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Arduino is the open source   electronics prototyping platform based on the micro controller . Arduino is a single board platform intended to make the application of interactive objects .Arduino  hardware consists of  everything needed to support the micro controller,  all you need to do is just simply connect it to a computer with a USB cable/power it with a Ac to Dc adapter or battery to use it.

About Arduino UNO

The current version of the Arduino hardware reference design is   "Arduino UNO"  .The Arduino UNO is one of the more popular boards of  the Arduino family and  it is a great choice for beginners.
Arduino UNO  has
→  ATmega328 micro controller,
→ operating voltage of 5V. 
→ 14 digital input/output pins ,  6 analog inputs,
→  32KB flash memory(ATmega328)  and
→ clock speed of  16Mhz.
→  a USB connection, a power jack, and a reset button.

Why Arduino?

Arduino is an open source electronics prototyping platform , easy to use hardware and software. It is intended for anyone interested in creating interactive objects. Arduino is user friendly. we can take inputs from a variety of objects like sensors or switches , and we can control variety of objects like motors, and other physical outputs. 

How to use Arduino?

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In order to work with Arduino you need to purchase Arduino UNO Hardware kit or you can design your own Arduino. Arduino is programmable. You have to program it in order to use it. For programming an Arduino we use Arduino programming IDE(Integrated Development Environment). 

DOWNLOAD ARDUINO SOFTWARE  

Arduino does not need a separate  hardware ( programmer) in order to load new code onto the board ,We can simply use a USB cable to upload the program to the Arduino board.It is very easy to learn and program An Arduino.

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ARDUINO COOKBOOK  

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 APPLICATIONS OF ARDUINO 

 Arduino can interact with LED's, motors, speakers, GPS units, cameras,internet, WI-fi ,smart phones  and and many electronic devices. It is very easy to control these electronic devices by using  Arduino. Arduino is used in many electronics and robotics projects and it is a great choice for beginners. It's a fun way to automate everything, enabling you to control simple devices. Many innovative projects have been designed by make use of Arduino.


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DIFFERENT TYPES OF REGISTERS

BINARY CELL:

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A binary cell is a memory allocation element that can store one bit of information(1 or 0).
We have Binary cell with logic '1' and logic '0'. A binary cell is referred as bit.

REGISTER:

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A set of binary cells is called a register. A register is characterized by
1)name of the register.
2)number of binary cells in it.

Different types of Registers

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DDR,PIN and PORT registers are frequently used in coding of an MC.
These registers are used to give instructions to the MC as of which pins are used as input/output pins.

1.DDR-Data Direction Register

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→This register is used to tell us about which pins in a particular port are to be used as input pins and which pins are to be used as output pins.
→Setting a bit in the DDR register to logic 1 will makes the corresponding pin as output pin.→Setting a bit in the DDR register to logic 0 will make the corresponding pin an input pin.
Ex:1)DDRA=0b11110000
the above statement means that the first 4 pins of port A(PA0-PA3) are set as input pins and the last four(PA4-PA7) are set as output pins.

2.PIN Register

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→This register is used for the ports that are configured as the input ports.
→The inputs at each pin of the input port are stored in this PIN register.
→Setting a bit as logic 1 in PIN register means that,that particular pin in that specified port has been used for input operation.

→Setting a bit to logic 0 means that,that particular pin in that specified port has not been used to give input.
Ex:1)PINA=0b11110000
the above statement means that first 4 pins are not used to give input and the other 4 have been used to give input.

3.PORT register

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→This register is used for the ports that are configured as the output ports.
→The outputs at each pin of the port are stored in the PORT register.
→Setting a bit as logic 1 in this register means that,that particular pin in that specified port has been used to take the output.
→Setting a bit as logic 0 means that,that particular pin in that specified port has not been used to take the output.
Ex: 1)PORTA=0b11110000
The above statement means that first 4 pins have not been used to take output..but other pins have been used.

ATMega16 MICROCONTROLLER

At mega is the one of the IC series of a Micro controller. At mega 16 has 16 KB of flash memory. At mega 16 micro controller is a 40 pin wide DIP(Dual Inline Package) chip of At mega series by ATMEL.In At mega 16 Micro controller
At →stands for the company that manufactures Micro controllers i.e. Atmel Corporation.
mega→ stands for family/series of Micro controller.
16→stands for the flash memory of the micro controller ,Here At mega 16 has 16KB of flash memory.

Now we need to know about At mega 16 Micro controller and It's PIN configuration. Every MC is characterized by its PIN configuration.
Atmega 16 micro controller has 40 Pins in which 32 pins(PA0-PA7,PB0-PB7,PC0-PB7,PD0-PD7) are bidirectional and 8(Reset,vcc,Avcc,ref,Aref,Grnd,Xtal1,Xtal2) pins are fixed.
A PIN is input/output pheripheral of a Micro controller. A PORT is collection of 8 pins. Atmega 16 has four ports namely PORTA,PORTB,PORTC,PORTD.
PIN 1-8     → PORTB
PIN 14-21 → PORT D
PIN 22-29 → PORT C
PIN 33-40 → PORT A

PIN DESCRIPTION:

PA0-PA7,PB0-PB7,PC0-PC7,PD0-PD7  are the set of pins used for bidirectional input and output operations.
RESET         → To reset the input.
VCC,AVCC →  For Digital supply voltages.
XTAL1        →   Input to the inverting oscillator amplifier.
XTAL2        →   Output of the inverting oscillator amplifier
AREF          →   Reference pin for ADC
GND            →  Ground.

APPLICATIONS:

 As these Micro controllers are programmable we can use them in electronic devices where artificial intelligence is required.These micro controllers are used in robotics projects like Line follower and Maze Solver etc.,
  

MICROCONTROLLER

What is a Micro Controller?

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Micro Controller is the most commonly used IC(Integrated Circuit).If a circuit consists of various circuit elements ,then placing thousands of such components in a small chip becomes an IC. We can simply say that " Micro controller is a small computer on a Single IC which contain RAM,Memory and Input/Output peripherals' .

Using of Micro Controller is a prototype or a real time Application. In order to communicate with Micro Controller you need input/output peripherals.

In MC pins are used as peripherals.We can use Microprocessor for the same purpose also. But there are some difference between Microprocessor and Micro Controller .

DIFFERENCES BETWEEN MICRO CONTROLLER AND MICROPROCESSOR

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MICROPROCESSOR:

1.Micro Processor can perform no of tasks and run variety of programs simultaneously.
For example, you can listen to music while writing some thing in your writer or doing work in your web browser etc.,
2.These are costly. Efficiency is more as compared to micro controllers.
MICRO CONTROLLER:
1. Micro controller is a computer on a chip optimized to control electronic devices. Micro controller is used to perform single task such as controlling a specific system.
2.Efficiency is more.These are economical and have wide range of uses.

But the reason for using Micro controller is that it is economical and has wide range of uses. We can use Micro Controllers in small projects and application where use of  microprocessor may not require.

Micro Controllers are programmable.You have to program them in order to use them. It has its own programming language and compilers. Program is fed into its memory. When MC is on its works according to the program.

APPLICATIONS

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Micro Controllers are used in many electronic projects where artificial intelligence is required. These are used in Robotics . If you want to move your Robot then you can simply program your Micro Controller and you can control your robot.these are used in many applications like ATM machines, cellphones,pen drives,laptops and in many electronic gadgets etc.

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And also Learn about :TRANSISTORS