The Engineering Projects

Diode: Definition, Symbol, Working, Characteristics, Types & Applications

Hi Guys! Hope you are doing great. Today, we will have a look at an electronic component named Diode. We will discuss Diode working, Symbol, Applications and characteristics in detail.

A diode is an electronic component, that allows the flow of current in one direction only. It exhibits low resistance in one direction and very high resistance in the opposite direction. Whoever has been a science student, knows about diodes. Although it seems to be a tiny component of a circuit, apparently it is true but it has a lot of complexities or you can say, it's a storm in a teacup.

Diodes are normally used in rectifiers, where they convert AC signals to DC signals. They come with a wide range of applications including power conversion, radio modulation, logic gates, temperature measurements and current steering. I'll try to cover everything related to diodes so let's get started:

Diode Definition

• A diode is a 2-terminal, basic discreet electronic component, made up of semiconductor material, which allows a unidirectional flow of current through it, i.e it only conducts current in one direction.
• A diode is analogous to a uni-directional water flow valve, which allows the water to flow in one direction but restricts it to flow backward.
• Diode consists of two terminals, named:
  • Anode (+).
  • Cathode (-).
• These terminals are connected to two doping regions:
  • P-Type region.
  • N-Type region.
• The P-Type region consists of positively charged ions called Holes, while the N-Type region consists of negatively charged electrons. We will discuss its construction in detail later.

• In a diode, current flows from Anode to Cathode(diode acts as a closed switch), but if the current flows in the opposite direction(i.e. from Cathode to Anode), the diode will block it, so we can say, the diode is acting as an open switch.

Diode Symbol

• The diode symbol and its real package are shown in the below figure:

• The arrowhead in a diode symbol represents the direction of the current flow i.e. current can flow from anode to cathode.

Construction of Diode

Now let's have a look at the construction of a diode:

• A diode is normally made up of a semiconductor material i.e. silicon, germanium, gallium arsenide etc.
• Two crystals of the same semiconductor material(normally silicon) are doped with different types of impurities, one crystal with pentavalent impurity, while the second one with trivalent, to create two types of semiconductor materials named:
  • P-Type Semiconductor: Majority Charge Carriers are Holes(+).
  • N-Type Semiconductor: Majority Charge Carriers are Electrons(-).
• When these two semiconductors are joined/merged together, the free electrons from the N-Type start to move towards the P-Type region, while the Holes start moving towards the N-Type region.
• At the border of these two regions, electrons get combined with Holes and neutralized.
• These neutralized atoms create a layer at the border(of N-Type & P-Type regions) and stop the flow of electrons & Holes. This newly created third layer/region is called the depletion region.
• The depletion region is very small in size and acts as a barrier for the flow of charge carriers(i.e. electrons & Holes) from the N-type to P-type region.
• Below diagram will give you a better idea of Diode construction:

• As you can see in the above figure, we have 3 regions in a final diode, named:

1. N-Type Region: Majority Charge Carriers are Electrons(-).
2. P-Type Region: Majority Charge Carriers are Holes(+).
3. Depletion Region: No Charge(Neutral)

• Two electrically conductive electrodes/probes are connected to these two Regions and are called:
  • Cathode: Connected to N-Type Region.
  • Anode: Connected to P-Type Region.

You must have understood by now, how diodes are constructed? Now, let's have a look at How diode works?

Diode Working

As we discussed in the above section, when two semiconductor materials are merged together, a momentary flow of charge carriers occurs, which results in the creation of a depletion region. This state of the diode is normally termed as Zero Biasing State, as there's no power applied at any terminal. In operational mode, the diode has two other biasing states, named as:

• Forward biased.
• Reverse biased.

Diode as Forward Biased

• The PN Junction created at the center of two regions is very small but it's powerful enough to stop the free electrons from passing through it.
• So, if we could provide some external power to these electrons, they can break this barrier and can make their entry into the P-Type region.
• This external power required to overcome the depletion region is normally termed as a Forward Threshold Voltage of diode.
• This threshold voltage value depends on the semiconductor material used in the diode construction i.e. for silicon it's +0.7V and for Germanium, it's +0.3V.
• So, for a normal diode, if we provide an external power of +0.7V, the electrons will overcome the depletion region and in simple words, the current will start flowing through the diode.
• As you can see in the below figure, the positive terminal of the battery is connected with the anode of the diode and as we will provide a voltage greater than its threshold voltage, the diode will start conducting and is said to be acting as forward biased.
• In forward biasing conditions, an ideal diode has zero resistance, but as I told you earlier, an ideal condition does not exist.

Diode as Reverse Biased

• If the polarity of the applied power is reversed i.e. positive terminal of the battery gets connected with the cathode(-), while the negative terminal gets connected with the anode(+), the depletion region will start to increase.
• In this state, the diode won't allow the current to flow through it and is said to be acting as reverse biased.
• In a reverse Biased state, the diode acts as an open switch.
• The PN junction in reverse biasing offers a very high resistance due to the thickness of the depletion region.
• A diode in ideal condition when reverse biased has infinite resistance.

History of Diode

• Introduced in 1906, the first semiconductor diode was named as Cat's Whisker Diode that was fabricated using mineral crystals.
• Mostly, diodes are designed using silicon because it can handle high temperature, however, germanium is also used when low voltage drop is required.

• When there is no applied voltage across the diode terminals, the diode will not conduct and very thin depletion region exists with no charge carriers around the pn junction of the diode.
• The diode will only conduct when applied voltage at the forward biased condition is greater than the diode built-in potential and it allows the flow of electrons from the cathode to the anode.
• Don't get confused with the arrow sign of the diode pointing from the anode to the cathode. It shows the conventional current flowing from anode to cathode. Conduction will be carried out from cathode to anode when a certain voltage above built-in potential is applied.

 

• A diode will stop conducting when the applied voltage is reverse biased and allows the depletion region to expand, blocking the flow of current. However, when a reverse biased voltage is too large, it allows the small current to flow which is called leakage current. It is too small that most of the time it is ignored while considering the current ratings.
• Similarly, when the reverse biased voltage is too large, it allows the depletion region to expand too much till it collapses, reaching a condition called breakdown, which appears to be very harmful for the quality and operation of the device.
• When we check the value of resistance by multimeter, it shows the low value at one terminal and high value at other terminal which indicates diode is working. It doesn't indicate the actual value of the resistance, instead, it shows the voltage drop across the pn junction.
• For silicon diodes, the forward voltage drop is 0.7 V, which is the voltage required to overcome built-in voltage in order to start the flow of current from cathode to the anode. Similarly, forward voltage drop for germanium is 0.3 voltage which makes it an ideal choice for the applications where low voltage drop is required.
• The voltage drop is highly dependent on the current flowing through the diode, however, it remains constant over a wide range of currents.

Junction Diodes

Diodes are divided into two types based on the formation of the junction between the terminals.

p-n junction Diode

• A pn junction diode is made from semiconductors like silicon or germanium where an N-type region is created with the help of negative charge carriers called n-type semiconductor while the P-type region is created with the addition of positive charge carriers called p-type semiconductors.
• Initially, there is no flow of current between two regions until they are joined together, resulting in a formation of pn junction where movement of electrons starts from N-type semiconductor to P-type semiconductor.

• There exists a region around pn junction where there are no charge carriers called depletion region. When depletion is very thin, indicates a conduction from N-type region to P-type region. When deletion region is very large, indicates no or little flow of current between two regions.
• The diode action takes place around the pn junction. When forward voltage potential more than built-in potential is applied between the diode terminals, it allows the flow of electrons from N-type region to P-type region, while blocking the flow of electrons in reverse order.
• Foward biased mode means the flow of electrons from N type to P type region. Reverse biased mode means no flow of electrons, blocking the current in other direction.

Schottky Diode

• Schottky diode is another type of junction diode where the junction is formed using metal-semiconductor instead of using p-n junction. It is an ideal choice for the applications where high switching speed is required.

Current-Voltage Characteristics

The voltage in V-I curve shows the voltage applied across the diode terminals and current shows the corresponding current obtained as the result of the applied voltage. Based on needs and requirements, the V-I characteristics of the diode can be customized using the suitable semiconductor material and doping concentration of impurities during the manufacturing of the device.

• The depletion region housed between the pn junction shows how the movement of electrons between the two N-type and P-type regions takes place.
• When pn junction is formed, the electrons from N-type region transfers to the P-type region, where they join the holes present in the P-type region.
• When electron combines the hole, the resulting pair disappears and the region around pn junction gets depleted with no charge carriers present. Resulting depletion region around the pn junction acts as an insulator.
• It is important to note, the width of depletion region cannot exceed without limit. When an electron-hole pair is created, it results in the formation of positively charged ion in the N-type region and negatively charged acceptor ion in the P-type region.
• As the formation of electron-hole pair proceeds, it results in the creation of built-in potential where increasing electric field developed around the depletion region, stops the further formation of an electron-hole pair.

Foward Biased Mode

• When the external voltage applied between the diode terminals comes with opposite polarity as the built-in potential, it starts the current flow where depletion region acts as a conductor. In this case, the depletion region formed around the pn junction will be very thin.
• The built-in potential is different for different diodes i.e. 0.7 for silicon and 0.3 for germanium.
• If the external voltage of opposite polarity with more than 0.7 V is applied between the diode terminals in case of a silicon diode, it allows the current to flow from anode to cathode. The diode is considered as "turned on" in this case.
• The voltage above which diode starts conducting through depletion region around the pn junction is called forward threshold voltage which is different than the built-in voltage.

Reverse Biased Mode

• When the external voltage applied between the diode terminals comes with the same polarity as built-in potential, it allows the depletion region to expand and stops the flow of current where depletion region acts as an insulator.

Types of Diodes

There are many types of diodes available in the market which are mainly used for the customization of voltage or current. Most of the pn junction diodes are made from silicon and germanium. Before the inception of these power diodes, selenium was used to manufacture the diodes.

Selenium diodes come with low efficiency as compared to silicon diodes, because high forward voltage around 1.4 or 1.7 V is required to start conducting around the pn junction, resulting in the need of much larger heat sink. Following are the most commonly used diodes in the electronic devices.

LED Diodes

• These diodes are made from the crystalline substance that emits light in different colors like red blue green or orange, depending on the crystalline material used in the diode.
• These diodes emit incoherent, narrow-spectrum light, capable of producing wavelengths in the wide range.
• Most of the LED diodes are low-efficiency diodes, which make them an ideal choice for the signal applications. LED diodes are also used in the formation of opto-isolator.

Avalanche Diodes

• These diodes are very identical to Zener diodes, where they start conducting in the reverse direction when reverse bias voltage becomes greater than break down voltage. These diodes come with an ability to break down at a certain voltage, without destroying them completely.
• Both Zener and Avalanche diodes are quite similar with respect to their mode of operation with one practical difference i.e. both didoes exhibit temperature coefficient with opposite polarities.

Zener Diodes

• Zener diodes, also termed as reverse breakdown diodes, are the diodes that conduct in reverse bias condition.
• Zener breakdown effect occurs at a very specific voltage, making them suitable for use as a precision reference voltage.
• In reference circuits, temperature coefficient balancing can be achieved by using a combination of zener diodes and switching diodes.
• Both avalanche and zener diodes fall under the category of breakdown diodes and electrically they response quite similar with one exception i.e. zener diodes operate with a breakdown voltage below 5 V, while avalanche diodes operate with a breakdown voltage above 5 V.

Crystal Diodes

• Crystal diode, also known as Cat's Whisker diode, is point contact diode which is not easily available in the market. This diode comes with a thin metal, known as an anode, and semiconductor crystal, known as a cathode.

Photodiodes

• Photodiodes are composed of semiconductor materials that are light sensitive, making them an ideal choice for solar cells and optical communications.
• These diodes are mostly available in single diode package, however, single dimensional or double dimensional array combination is also widely available.

Applications

Diodes allow the current to flow in one direction which makes them suitable for most of the applications where current controlling is prerequisite. Following are the major applications of the diodes.

ONE. Logic gates are designed using diodes with other electronic components.

TWO. Diodes are also used as a waveform clipper, where they clip the negative or positive peak of the signal in order to attain specific voltage.

THREE. Didoes are helpful for temperature measuring because the forward voltage drop across them is very sensitive to temperature. Most of the diodes come with negative temperature coefficient which remains constant above 20 Kelvin.

FOUR. Diodes are widely used for the demodulation of amplitude signal. The amplitude of AM signal is directly proportional to the original audio signal and comes with positive and negative peaks of the carrier wave. The diode is used to rectify the AM radio signal, resulting in only positive peaks of the carrier wave. A filter is applied in order to extract the audio signal from radio carrier wave, which then produces sound waves when applied to the amplifier.

FIVE. Rectifiers are made from diodes which widely replace the commutator for converting AC signal to DC signal.

SIX. Some electronic circuits are very sensitive and show high spikes in the voltage during the execution of the project. These diodes are used to prevent the circuits from high voltages spikes which appear to be very damaging, if not controlled properly, in the early stages.

That's all for today. I hope you have found this article useful. If you're unsure or have any question, you can approach me in the comment section below. I'd love to help you according to best of my expertise in any way I can. Feel free to keep us updated with your suggestions, they help us to provide you quality work that resonates with your needs and demands. Thanks for reading the article.

Introduction to 2n6491

Hello Friends! Hope you are doing great. We always come up with useful information that helps you solve your problems and keeps you updated with the knowledge that resonates with your needs and demands. Today, I am going to unlock the details on the Introduction to 2n6491. It is an NPN power transistor mainly used for general purpose amplification and switching purpose. It exhibits high DC current gain and comes with TO-220 package. I'll break down all information related to this transistor in easy steps, so you can grab the main concept easily. Let's dive in and explore what is this about and its main applications.

Introduction to 2n6491

• 2n6491 is an NPN (negative-positive-negative) bipolar junction transistor mainly used for general purpose amplification and switching purpose.
• It has three terminals used for external connection with the electronic circuits called emitter, base, and collector.
• All these three terminals are different in terms of their doping concentration. An emitter is highly doped as compared to base and collector.
• The base is lightly doped which is responsible to trigger the electron reaction in the transistor.
• The collector is moderately doped which is used to collect the electors from base terminals.
• When a voltage is applied at the base terminals, it gets triggered and starts the electron reaction.

• The base terminal then draws small current which is used to control large current at the collector and emitter side.
• This transistor is a current controlled device where small current at the base side is used to control the large current at the other terminals.
• The number of electrons from emitter side is diffused to the base side where they act as minority carriers. Holes behave as majority carriers at the base side.
• When electrons come from the emitter side, it will combine with the holes in the base terminal.
• However, a base cannot control all number collected from the emitter side, resulting to diffuse the remaining electrons to the collector side.
• Diode plays a vital role in the construction of this transistor. When two diodes are joined back to back, they constitute a transistor.

2n6491 Pinout

• The following figure shows the pinout of this NPN transistor. It consists of three terminals called emitter, base, collector.

• Free movement of electrons from a base to collector terminal occurs when a voltage is applied at the base terminal. Actually, movement of electrons is nothing but a bridge between emitter and collector.

Circuit Diagram of 2n6491

• Following figure shows the circuit diagram of this NPN transistor.

• The voltage at the base side is positive with respect to the emitter and current flows from the emitter to collector.
• The amount of current we get at the output side is highly dependent on the small current at the base side which is the result of the voltage applied at the base terminal.
• The emitter current is equal to the sum of base and collector current because doping concentration of emitter is more than base and collector, resulting in a more current present at the emitter terminal as compared to other terminals.
• Common emitter current gain is an important factor determining the characteristics of the transistor. It is the ability of current being amplified. It is called beta and denoted by ß which is a ratio between collector current and base current. Beta plays an important role in the amplification purpose and also known as an amplification factor.
• Similarly, the common-base current gain is another important factor which is obtained when base to collector voltage is constant. It is called alpha and denoted by a. It is a ratio between collector current and emitter current. The alpha value is always less than one and lies between 0.95 and 0.99. However, more often than not, alpha value is taken as unity.
• This NPN transistor contains electrons as majority charge carriers while PNP transistors contain holes as majority charge carriers.

Absolute Maximum Ratings

• Following figure shows the absolute maximum ratings of 2n6491.

• These are the stress ratings which, if exceed from the absolute maximum ratings, can damage the device at large.
• If these ratings are applied for the maximum period of time, they can affect the device reliability.
• We can see from the figure, collector-emitter voltage is 80 and collector-base voltage is 90.  And maximum power dissipation is 75 W.
• It is important to consider these absolute maximum ratings before you pick this transistor for your project. These ratings play a vital role in the execution and performance of the whole project.
• If ratings of this transistor don't match with your requirements, then you can try other transistors like 2n3903 that comes with different ratings.

Applications

• This transistor is mainly used for general purpose amplification.
• Fast switching applications involve this transistor.

That's all for today. You must have a look at MOSFET which is a unipolar voltage controlled device different than this NPN transistor which is a current controlled bipolar device. If you're unsure or have any question, you can ask me in the comment section below. I'd love to guide you according to best of my expertise in any way I can. Keep us updated with your valuable suggestions, they allow us to give you quality work that aligns with your needs and demands. Thanks for reading the article.

How to Create PWM in Raspberry Pi 3

Hello friends, I hope you all are doing great. In today's tutorial, I am going to explain How to Create PWM in Raspberry Pi 3. In our previous tutorial, we have seen How to Create GUI in Raspberry Pi 3, & we have also controlled an LED from the GUI Buttons. So, I am gonna take that project and will add PWM code in it. So, I would recommend you to first have a look at LED Blinking with Raspberry Pi 3 in which we have designed this simple project and then check How to Create GUI in Raspberry Pi 3, where we have controlled that LED digitally with GUI. But today, we are gonna control the intensity of this LED by creating a PWM Pulse in Raspberry Pi 3. Along with that, we are also gonna have a look at How to use Scale in Raspberry Pi 3. I will add a new scale in the same GUI and when we change the value of this scale and the LED intensity will also change. So, let's get started with How to Create PWM in Raspberry Pi 3:

Create PWM in Raspberry Pi 3

• In our previous post, we have created a simple GUI to control an LED, that GUI is shown in below figure:

• I hope you have remembered the Grid system which we discussed in last lecture, we are now gonna add a new scale in our GUI and we will place it at row = 1 & column = 2.
• It's on the right side of 'LED OFF' button. Here's the code for it.

Scale1 = Scale(Gui, from_=0, to=100, orient = HORIZONTAL, resolution = 1, command = ChangePWM)
Scale1.grid(row=1,column=2)

• We have created a new slider and it's value starts from 0 and it ends at 100.
• Its orientation is horizontal, by default its vertical.
• We have assigned it a function named as ChangePWM and this function will execute whenever we change the value of this slider.
• As, we haven't yet created the function so if you will change its value then it will give error.
• If you run it, it will look something as shown in below figure:

• I have given it a value from 0 to 100 because our PWM pulse value also goes from 0% to 100%.
• If you don't know much about PWM then you should have a look at How to use Arduino PWM Pins, just read the PWM part I have discussed it in detail there.
• In raspberry Pi 3, we have Pin # 12 and Pin # 32 as PWM Pins but I have tried different I/O Pins and this PWM commands works quite fine on all of them. :P
• Anyways, I am going to use Pin # 12 of pi 3 so change this value from 11 to 12.
• So, first of all we are gonna create our PWM frequency, which I have set to 5000.
• After that I have started my PWM Pulse with a value of 0.

PwmValue = GPIO.PWM(LED, 5000)
PwmValue.start(0)

• As you can see in above code our PwmValue is 0 so which means our LED will remain OFF.
• Now, we have to create our slide function ChangePWM.
• So, add the below code after your Buttons functions:

def ChangePWM(self):
    PwmValue.ChangeDutyCycle(Scale1.get())

• Just make sure to add this self in functions' name.
• Slide function works a little different than Button function, so we have to add this self. If you have ever worked on embedded then we add (void). :P
• ChangeDutyCycle is the command to change duty cycle of our PWM Pulse.
• So, we are simply getting value of our Scale and then giving this value to our pwm pulse which in turn changes the intensity of our LED.
• So, if we have 0 on slider then our LED will be at lowest intensity so means OFF and at 100 it will glow at maximum intensity or 5V.
• Here's our complete code:

# ************************************************************************** #
# ****                                                                  **** #
# *********** Code Designed by www.TheEngineeringProjects.com ************** #
# ****                                                                  **** #
# ****************** How to Create a GUI in Raspberry Pi 3 ***************** #
# ****                                                                  **** #
# ************************************************************************** #

# Importing Libraries

import RPi.GPIO as GPIO
import time
from tkinter import *
import tkinter.font

# Libraries Imported successfully

# Raspberry Pi 3 Pin Settings

LED = 12 # pin12
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD) # We are accessing GPIOs according to their physical location
GPIO.setup(LED, GPIO.OUT) # We have set our LED pin mode to output
GPIO.output(LED, GPIO.LOW) # When it will start then LED will be OFF

PwmValue = GPIO.PWM(LED, 5000)
PwmValue.start(0)

# Raspberry Pi 3 Pin Settings

# tkinter GUI basic settings

Gui = Tk()
Gui.title("GUI in Raspberry Pi 3")
Gui.config(background= "#0080FF")
Gui.minsize(800,300)
Font1 = tkinter.font.Font(family = 'Helvetica', size = 24, weight = 'bold')

# tkinter simple GUI created

def ledON():
    GPIO.output(LED, GPIO.HIGH) # led on
    Text2 = Label(Gui,text=' ON ', font = Font1, bg = '#0080FF', fg='green', padx = 0)
    Text2.grid(row=0,column=1)

def ledOFF():
    GPIO.output(LED, GPIO.LOW) # led off
    Text2 = Label(Gui,text='OFF', font = Font1, bg = '#0080FF', fg='red', padx = 0)
    Text2.grid(row=0,column=1)

def ChangePWM(self):
    PwmValue.ChangeDutyCycle(Scale1.get())

Text1 = Label(Gui,text='LED Status:', font = Font1, fg='#FFFFFF', bg = '#0080FF', padx = 50, pady = 50)
Text1.grid(row=0,column=0)

Text2 = Label(Gui,text='OFF', font = Font1, fg='#FFFFFF', bg = '#0080FF', padx = 0)
Text2.grid(row=0,column=1)

Button1 = Button(Gui, text=' LED ON', font = Font1, command = ledON, bg='bisque2', height = 1, width = 10)
Button1.grid(row=1,column=0)

Button2 = Button(Gui, text=' LED OFF', font = Font1, command = ledOFF, bg='bisque2', height = 1, width = 10)
Button2.grid(row=1,column=1)

Scale1 = Scale(Gui, from_=0, to=100, orient = HORIZONTAL, resolution = 1, command = ChangePWM)
Scale1.grid(row=1,column=2)

Text3 = Label(Gui,text='www.TheEngineeringProjects.com', font = Font1, bg = '#0080FF', fg='#FFFFFF', padx = 50, pady = 50)
Text3.grid(row=2,columnspan=2)

Gui.mainloop()

• You can download this PWM code by clicking the below button:

[dt_default_button link="https://www.theengineeringprojects.com/RaspberryPi3/How to Create PWM in Raspberry Pi 3.rar" button_alignment="default" animation="fadeIn" size="medium" default_btn_bg_color="" bg_hover_color="" text_color="" text_hover_color="" icon="fa fa-chevron-circle-right" icon_align="left"]Download PWM Pulse Code for Raspberry Pi 3[/dt_default_button]

• So, now let's run our code and get the results. I have shared the below image in which I have set the value of scale to 15.

So, that was all about How to Create PWM in Raspberry Pi 3. In our coming tutorial, we are gonna have a look at How to Control Direction & Speed of Dc Motor with Raspberry Pi 3. So, will meet you guys in next tutorial. Till then take care and have fun !!! :)

How to Create a GUI in Raspberry Pi 3

Hello friends, I hope you all are doing great. In today's tutorial, I am going to show you How to Create a GUI in Raspberry Pi 3. There are many different third party libraries available and the one I am going to use is tkinter. I have tried these libraries and I liked it the most so that's why I'm gonna use it in my future Raspberry Pi 3 Projects. In our previous tutorial on Raspberry Pi 3, we have had a look at LED Blinking using Raspberry Pi 3. So, today I am gonna work on the same project and we will add a GUI in it. GUI is an abbreviation of Graphical User Interface and it is used to give a presentable form to your project. We will add some buttons on our GUI and we will turn ON or OFF our LED using buttons. It's quite a basic tutorial but its essential to cover before working on bigger projects. So, let's get started with How to Create a GUI in Raspberry Pi 3:

How to Create a GUI in Raspberry Pi 3

• I hope you have already Setup your HDMI LCD with Raspberry Pi 3, as we have done in our previous tutorials.
• Here's an image of our final setup:

• So open a new File in your Python IDLE and save it, I have given it a name CreateGUI.py
• First of all we are gonna import our libraries in python, so here's the code:

# ************************************************************************** #
# ****                                                                  **** #
# *********** Code Designed by www.TheEngineeringProjects.com ************** #
# ****                                                                  **** #
# ****************** How to Create a GUI in Raspberry Pi 3 ***************** #
# ****                                                                  **** #
# ************************************************************************** #

# Importing Libraries

import RPi.GPIO as GPIO
import time
from tkinter import *
import tkinter.font

# Libraries Imported successfully

• In the above code you can see, we have imported a new library which is tkinter library and we have also imported font from it.
• Now we are gonna do some initial settings of our Raspberry Pi 3 LED Pin, as we have have done in LED Blinking using Raspberry Pi 3.
• Here's the code for that:

# Raspberry Pi 3 Pin Settings

LED = 11 # pin11
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD) # We are accessing GPIOs according to their physical location
GPIO.setup(LED, GPIO.OUT) # We have set our LED pin mode to output
GPIO.output(LED, GPIO.LOW) # When it will start then LED will be OFF

# Raspberry Pi 3 Pin Settings

• In the above code I have set all warnings to False as I think warnings are just annoying. :P
• After that I have set our GPIO mode to Board because its lot easier to remember Pin Number as their number on board.
• You can set this mode to BCM as well.
• Next we have made our LED Pin output and have made it Low as I wanna keep my LED in OFF state when project starts up.
• Now let's place some code for GUI initialization and basic settings,here's the code:

# tkinter GUI basic settings

Gui = Tk()
Gui.title("GUI in Raspberry Pi 3")
Gui.config(background= "#0080FF")
Gui.minsize(700,300)
Font1 = tkinter.font.Font(family = 'Helvetica', size = 24, weight = 'bold')

# tkinter simple GUI created

• First of all, I have create an object named Gui, which is actually my GUI Board.
• Then I have given it a title, which will appear as name of this GUI or software.
• I have made the background light blue, it will look good.
• the minimum size, I have set is 700 x 300, its in pixels (x, y).
• Finally we have set our Font, which we are not using yet but will use in next section.
• Now if you run your code then you will get something as shown in below figure:

• You can see in above figure that we a got a simple board and the title is also there.
• So, now let's add some Labels first on our GUI in pi 3:

Text1 = Label(Gui,text='LED Status:', font = Font1, fg='#FFFFFF', bg = '#0080FF', padx = 50, pady = 50)
Text1.grid(row=0,column=0)

Text2 = Label(Gui,text='OFF', font = Font1, fg='#FFFFFF', bg = '#0080FF', padx = 0)
Text2.grid(row=0,column=1)

• I think these codes are self explanatory, I have added two texts "LED Status: " and "OFF".
• I have given them the Font1 which we created in last section and then the background is again white, and I have also added some padding in x and y direction so that it won't touch the borders.
• In this GUI tkinter coding we have grid system. The below image will clear the idea:

• We have added both our Labels in first row, so here's the output of above code:

• Now let's add two buttons below these Labels, which will control our LED and will turn it ON and OFF.
• Here's the code for adding Buttons in GUI using tkinter:

Button1 = Button(Gui, text=' LED ON', font = Font1, command = ledON, bg='bisque2', height = 1, width = 10)
Button1.grid(row=1,column=0)

Button2 = Button(Gui, text=' LED OFF', font = Font1, command = ledOFF, bg='bisque2', height = 1, width = 10)
Button2.grid(row=1,column=1)

• You have seen in above code that now these two buttons are in second row so they will come below these Labels.
• The only thing worth mentioning here is the Command, its actually a function which will execute on pressing that button.
• So, now we need to add these functions above Label codes.
• Just try to understand the code rite now, I have shared the complete file below, which you can easily download.
• So, here's these two functions' codes:

# Function for Buttons started here

def ledON():
    GPIO.output(LED, GPIO.HIGH) # led on
    Text2 = Label(Gui,text=' ON ', font = Font1, bg = '#0080FF', fg='green', padx = 0)
    Text2.grid(row=0,column=1)

def ledOFF():
    GPIO.output(LED, GPIO.LOW) # led off
    Text2 = Label(Gui,text='OFF', font = Font1, bg = '#0080FF', fg='red', padx = 0)
    Text2.grid(row=0,column=1)

# Function for Buttons ended here

• In some cases you need to merge your columns or rows, for that you can use below code.
• In below code, I have merged the columns of last row by using 'columnspan=2' and added our site's link.
• It has merged the first two columns of last row and here's the code:

Text3 = Label(Gui,text='www.TheEngineeringProjects.com', font = Font1, bg = '#0080FF', fg='#FFFFFF', padx = 50, pady = 50)
Text3.grid(row=2,columnspan=2)

• And finally we need to add our main loop code, which is like while(1) in python, it is given below:

Gui.mainloop()

• Now run your code and you will get something as shown in below figure:

• I have combined all the above codes and here's it's final form, it's now easy to understand:

# ************************************************************************** #
# ****                                                                  **** #
# *********** Code Designed by www.TheEngineeringProjects.com ************** #
# ****                                                                  **** #
# ****************** How to Create a GUI in Raspberry Pi 3 ***************** #
# ****                                                                  **** #
# ************************************************************************** #

# Importing Libraries

import RPi.GPIO as GPIO
import time
from tkinter import *
import tkinter.font

# Libraries Imported successfully

# Raspberry Pi 3 Pin Settings

LED = 11 # pin11
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD) # We are accessing GPIOs according to their physical location
GPIO.setup(LED, GPIO.OUT) # We have set our LED pin mode to output
GPIO.output(LED, GPIO.LOW) # When it will start then LED will be OFF

# Raspberry Pi 3 Pin Settings

# tkinter GUI basic settings

Gui = Tk()
Gui.title("GUI in Raspberry Pi 3")
Gui.config(background= "#0080FF")
Gui.minsize(700,300)
Font1 = tkinter.font.Font(family = 'Helvetica', size = 24, weight = 'bold')

# tkinter simple GUI created

# Funtion for Buttons started here

def ledON():
    GPIO.output(LED, GPIO.HIGH) # led on
    Text2 = Label(Gui,text=' ON ', font = Font1, bg = '#0080FF', fg='green', padx = 0)
    Text2.grid(row=0,column=1)

def ledOFF():
    GPIO.output(LED, GPIO.LOW) # led off
    Text2 = Label(Gui,text='OFF', font = Font1, bg = '#0080FF', fg='red', padx = 0)
    Text2.grid(row=0,column=1)

# Funtion for Buttons ended here

Text1 = Label(Gui,text='LED Status:', font = Font1, fg='#FFFFFF', bg = '#0080FF', padx = 50, pady = 50)
Text1.grid(row=0,column=0)

Text2 = Label(Gui,text='OFF', font = Font1, fg='#FFFFFF', bg = '#0080FF', padx = 0)
Text2.grid(row=0,column=1)

Button1 = Button(Gui, text=' LED ON', font = Font1, command = ledON, bg='bisque2', height = 1, width = 10)
Button1.grid(row=1,column=0)

Button2 = Button(Gui, text=' LED OFF', font = Font1, command = ledOFF, bg='bisque2', height = 1, width = 10)
Button2.grid(row=1,column=1)

Text3 = Label(Gui,text='www.TheEngineeringProjects.com', font = Font1, bg = '#0080FF', fg='#FFFFFF', padx = 50, pady = 50)
Text3.grid(row=2,columnspan=2)

Gui.mainloop()

• If you got into any trouble then ask in comments.
• Now when you click on the "LED ON" Button then your LED will turn ON and when you click on the "LED OFF" button, then your LED will go OFF.
• LED status text on GUI will change from OFF to ON.
• Both Raspberry Pi 3 Screen and its hardware setup are shown in below figure: (click & zoom)

• Now when you click the LED OFF button then LED status will change from ON to OFF as shown in below figure:

• I hope you have got the main idea of How to create GUI in Raspberry Pi 3.
• In my coming tutorial, I will share many tutorials on raspberry Pi 3 in which we will create such simple GUIs and will display different sensors' values and will also control them.
• You can download this CreateGUI.py file by clicking the below button:

[dt_default_button link="https://www.theengineeringprojects.com/RaspberryPi3/CreateGUI.rar" button_alignment="default" animation="fadeIn" size="medium" default_btn_bg_color="" bg_hover_color="" text_color="" text_hover_color="" icon="fa fa-chevron-circle-right" icon_align="left"]Download CreateGUI.py File[/dt_default_button]

So, that was all about How to Create GUI in Raspberry Pi 3. I hope you have got the detailed idea of GUI creation. In my coming tutorial, we will have a look at How to Control DC Motor with Raspberry Pi 3. Thanks for reading, have fun !!! :)

Hostinger vs. Siteground: which one is better?

Hello friends, I hope you all are doing great. In today's tutorial, I am going to give you a detailed comparison, Hostinger vs. Siteground and will tell you which one is better? When it comes to website hosting, it can be considered an important part of the whole web development thing. If you thought that just creating a website would be enough to make it all successful, then you would definitely be wrong. There are many other factors that come to light when you build a website. Web hosting is one such factor. To find a popular and well-known web hosting service is really important for any web developer as it helps in the product development process. Plus, who wouldn’t want their websites to have the perfect ratings and reviews? Having the perfect web hosting service provider is the first step towards that goal of yours. But how do you get to know which one is the best one? Well, this is what we are going to tell you in this article.

Choosing One From A Whole Bunch

There is not a single doubt about the fact that the web is filled with hundreds of options for web-hosting services. We, as a data-driven world, are only concerned about the functionality of such services where we should be putting our main focus on the quality of the web hosting service provider. Web hosting services certainly form a huge part of the industry and there are numerous options from which you can make your own pick. But due to so many options, most buyers tend to get a bit overwhelmed and end up choosing the wrong product. Also, there is the risk of the fraud services as well. Sure, some of the web-hosting service providers are simply the best when it comes to offering the best services. But there are also many web hosting service providers that tend to provide mediocre services as they only care about their profit. So, to keep yourself safe from such service providers, it is important to take the decision wisely. An informative comparison between the different service providers is necessary. Well, you are just in luck this time as we have a new player in the web hosting industry. Hostinger is one of the best and the most popular web hosting service providers and is known all around the world. With the help of the fantastic features and budget-friendly rates, it has created a name for itself in the industry. You can check out more about Hostinger and its features from hostinger.com website. However, not just Hostinger but there are some other services that are known for providing the best web hosting services in the industry. Siteground is one such service that comes close in the competition. An older name in the market, Siteground has made quite a reputation for itself in the industry with the help of its features. So, how exactly do you get to know which one will be the best one for your website? Well, buckle up people because now is the time to compare between these two web hosting service providers to find out who the real winner is. To make your task even easier, we have done the comparison for you. Have a look down below.

Hostinger vs. Siteground

Webmasters and developers will understand the best about the quality of the website more than anyone else. But then again, sometimes it happens that they don’t really put that much of an effort in figuring out what the best web hosting company is. So, we are doing the task for you in here we shall be discussing and comparing the different parts of both the web hosting service providers Siteground and Hostinger to determine who wins. So, without wasting any more of your precious time, let’s get started with the comparison.

1. Pricing And Plans

A person’s budget is often the deciding factor when it comes to choosing the web hosting services. Well, to be honest, both the services might have everything similar, but not the price. The price of the monthly services of Siteground stands at $5.95, which is certainly not very much. However, when compared to the price of Hostinger, it is clear which one the better option is. The monthly price of the services of Hostinger is at $3.49 which makes it an affordable and well as a great solution. Also, when compared to the 6 subscription plans of Hostinger, the mere 3 options of Siteground doesn’t stand much of a chance.

2. Features

The features of the web hosting services are the ones that decide whether it is a good service provider or not. One of the best things to judge the quality of a website hosting service is to make sure that it has all the features. Well, when it comes to features, Hostinger again takes the lead with interesting and unique features such as Free Domain name registration option and Unlimited and free SSC storage option as well. Although most of the features of both the services are similar, these features are what make Hostinger the best web hosting service provider.

3. Uptime

The server uptime is a crucial thing when it comes to the performance of the website. So, don’t you think that you should use a service provider that has a record of the best uptime? I mean, why would choose a service which doesn’t guarantee an uptime at all times. The comparison between the uptimes of Siteground and Hostinger show that Hostinger is again the better choice. The uptime of Hostinger is 100% whereas Siteground’s uptime is at 99.9%. Well, it most certainly came close in this competition.

4. Website Loading Time

Another one of the crucial factors that help in the judging of the website performance is the website loading time. The longer it takes to load a website, the more impatient and uninterested the people will get. So it is needless to say that the web hosting services that offers a less website loading time obviously wins. In case of Hostinger, the time is 77ms whereas Siteground has got 504ms. So, Hostinger clearly gets the lead in here as well. From studying the different comparisons it can be clearly said that Hostinger is undoubtedly the better choice amongst the two website hosting service providers.

Introduction to BJT (Bipolar Junction Transistor)

Hey Guys! Hope you are doing great. Today, I am going to discuss the details on the Introduction to BJT (Bipolar Junction Transistor). It is an electronic component mainly used for amplification and switching purpose. As the name suggests, it is composed of two junctions called emitter-base junction and collector-base junction. Don't confuse BJT with regular transistors. A transistor is a semiconductor device, comes with three terminals that are used for external connection with electronic circuits. A transistor is termed as a trans resistor which is used as switch or gate for electronic signals. Small signals applied between one pair of its terminals are used to control much larger signals at the other pair of terminals. Actually, transistors are divided into two categories called unipolar transistor and a bipolar transistor. Bipolar junction transistor uses two charge carries i.e. electrons and holes while unipolar transistor like FETs (Field Effect Transistors) uses only one charge carrier. I hope you are aware of another type of transistors called MOSFET. I'll try to cover each and everything related to this bipolar junction transistor, so you find all information at one place. Let's get started.

Introduction to BJT

• Introduced in 1948 by Shockley, BJT is an electronic component mainly used for switching and amplification purpose.
• It is composed of three terminals called emitter, base, and collector, denoted as E, B and C respectively.
• This transistor comes with two PN junctions. The PN junction exists between emitter and base is called emitter-base junction and the PN junction exists between collector and base is called collector-base junction. Emitter-base junction is forward biased and the collector-base junction is reverse biased.
• In the start BJTs were made from germanium, however, recent transistors are made from silicon.
• BJT comes in two types called NPN transistor and PNP transistor.
• It is a bipolar device where conduction is carried out by both charge carriers i.e. electrons and holes. The number of electrons diffused in the base region is more the number of holes diffused in emitter region. Electrons behave as a minority carrier in the base region.
• Under normal conditions, when the emitter-base junction is forward biased it allows the current to flow from emitter to collector. When a voltage is applied at the base terminal, it gets biased and draws current, which directly affects the current at the other terminals.
• BJT is called a current controlled device where small current at the base side is used to control the large current at other terminals. All three terminals of the BJT are different in terms of their doping concentrations. The emitter is highly doped as compared to base and collector.

• The collector is moderately doped and its area is larger as compared to emitter area, allowing it to handle more power.
• When a voltage is applied, the majority of electrons from emitter are diffused into the base where these electrons act as minority charge carriers, making the holes in the base region majority charge carriers.
• As the base is very thin and lightly doped it cannot hold the number of electrons for too much time, allowing the electrons to diffuse from base to collector.
• Making a slight change at the voltage applied at the base-emitter terminals can cause a significant change at the current between emitter and collector terminals.
• This is the process used for amplification purpose.
• When the emitter-base junction is not forward biased the amount of current at the base and collector terminal is zero, no matter how much voltage is applied at the base terminal.
• Common-Emitter current gain is a term mostly used for BJTs. It is a ratio between collector current and base current. Similarly, a common-base current gain is defined as a ratio between collector current and emitter current. Most of the time its value is taken as unity.
• Construction of BJT is not symmetrical in nature. The lack of symmetry of BJTs is due to the difference in doping concentration between the terminals.
• Generally, BJTs are operated in forward-biased mode. Interchanging the emitter and collector allows the forward biased mode to change to reverse biased mode. This interchange causes a wide impact on the values of current gains, making them much smaller as they are in forward-biased mode.
• The mode of operation where an emitter-base junction is forward biased and the collector-base junction is reverse biased is called active region.

Types of BJT

BJTs are divided into two types based on the nature and construction of the transistor. Following are two main types of the BJT.

NPN

• NPN (negative-positive-negative) is a type of BJT where a P-doped layer of semiconductor exists between the two layers of N doped material.
• The P doped region represents the base of the transistors while other two layers represent emitter and collector respectively.
• NPN transistors are also called minority carrier devices because minority charge carriers at the base side are used to control large current at other terminals of the transistor.
• The current moves from an emitter to the collector where electrons act as a minority carrier at the base side.

PNP

• PNP (positive-negative-positive) transistor is a type of BJT where N doped semiconductor layer which acts as a base, is housed between the two layers of P doped material.
• The base uses small base current and negative base voltage to control large current at the emitter and collector side and voltage at the collector side is larger than the voltage at the base side.
• In PNP transistor current direction and voltage polarities are reversed as compared to NPN transistors.
• PNP transistors work in a similar way like NPN transistor with some exception i.e. holes are diffused through the base from an emitter and are collected by the collector.
• This transistor is rarely used for applications as conduction carried out by the movement of electrons is considered fast and holds more value as conduction by movement of holes.

Regions of Operations of BJT

Bipolar junction transistors come with different regions of operation. These modes of operations set a tone for current flowing from emitter to collector.

Forward Active Mode

• BJT comes with two junctions called emitter-base junction and collector-base junction. Emitter-base junction is forward biased and the collector-base junction is reverse biased.
• For amplification purpose, most of the transistors come with high common emitter current gain which shows the exact current and power gain required for amplification purpose.
• The collector-emitter current is largely dependent on the base current where small current at the base side is used to control the large current at the emitter and collector side.

Reverse Active Mode

• By interchanging the emitter and collector, transistor goes from active mode to reverse active mode.
• Most of the transistors are designed to afford high current gain, but reversing the role of emitter and collector makes the current gain very small as compared to forward biased region. This type of mode is rarely used unless a failsafe condition is required.

Saturation

• BJT exhibits saturation mode when both junctions are forward biased. This mode of operation is referred as a closed circuit which allows a large amount of current flowing from emitter to collector side.

Cut-off

• When the emitter-base junction is not forward biased, the transistor is said to have in the cut-off region where collector current and base current will be zero, no matter how much voltage is applied at the base terminal.

Three Basic Configurations of BJT

BJT is a current controlled device which is mainly used for amplification and switching purpose. There are three ways to connect this device with external electronic circuits called: 1. Common Base Configuration 2. Common Collector Configuration 3. Common Emitter Configuration The nature of the current being controlled at the output is different for different configurations.

Common Base Configuration

• Common base configuration is a configuration where the common base is shared between input and output signal.
• Voltage is applied at the emitter-base junction and corresponding output signal is obtained at the output across the base-collector junction.
• The base voltage is connected to some reference voltage or can be grounded in some cases with the intention of making common base between input and output signals.
• Following figure shows the circuit diagram of common base configuration.

• Current at the emitter side is quite large, where electrons are diffused into the base terminal. These electrons make a pair with some holes present in the base, while most of them leave the base and are collected by the collector.
• This type of transistor comes with remarkable high voltage characteristics which don't make it an ideal choice for many applications. In this configuration, an output and input voltage is in line with each other. The input characteristics of this transistor are quite identical to forward biased diode while output characteristics are similar to a regular diode and come with a high output to input resistance ratio.
• Common base current gain is a very important factor used in this configuration which is a ratio between collector current and emitter current. It is denoted by a alpha.
• a = Ic/Ie
• The alpha value ranges between 0.95 to 0.99, however, most of the time its value is taken as unity. High-frequency response of common base configuration makes it an ideal choice for single stage amplifier.

Common Collector Configuration

• This configuration is also known as voltage follower where the input is applied at the base terminal and output is taken from emitter terminal.
• This configuration is mainly used for impedance matching as the input impedance of this configuration is very high while output impedance is very low.
• Common collector configuration is termed as non-inverting amplifier where output signal and an input signal are in phase with each other.
• The current gain of this transistor is very large because the load resistance is at the receiving end of both collector current and base current, making it a suitable for amplification purpose.
• Hence very little voltage gain, around unity, can help in producing very large current gain.
• Following figure shows the circuit diagram of common collector configuration.

Common Emitter Configuration

• This configuration is widely used in transistor based amplifier, where an input signal is applied between emitter and base while the output is taken from emitter and collector.
• This configuration comes with highest current and power gain which makes it an ideal choice for amplification. Input impedance is connected to forward biased PN junction which shows low value while output impedance is connected to reverse biased PN junction which shows high value.
• Most of the transistors generally come with common emitter configuration because this exhibits the ideal power and current required for amplification purpose.
• Common emitter configuration is termed as inverting amplifier circuit where an input signal is out-of-phase with the output signal.
• Following figure shows the circuit diagram of common emitter configuration.

 

• The common emitter current gain of this transistor is very large as compared to a current gain of common base configuration which is a ratio between collector current and base current. It is denoted by ß beta which is the measure of current being amplified.
• ß = Ic/Ib
• Output current at the collector and emitter side is highly dependent on the current at the base side.
• Current at the emitter side is the sum of current at the base and collector side because emitter side is highly doped as compared to base and collector.
• Ie = Ib + Ic
• When the voltage is applied at the base terminal it triggers the electrons reaction which forces the electrons to move towards the collector side.
• Any small change at the voltage applied at the base terminal results in a very large change at the current obtained at the collector side.

Pros of BJTs

• Bipolar junction transistor comes with a large amplification factor.
• This type of transistor provides a better voltage gain.
• This transistor comes with a capability of operating in four regions i.e active region, reverse mode, saturation and cut-off region.
• BJT provides a better responese at higer frequiencies.
• BJTs also act as a switch.

Cons of BJTs

• BJT is very sensitive to heat and produces noise is some cases.
• The switching power of BJTs is very low as compared to unipolar transistors like FETs.

Applications

• BJTs come with two major applications called amplification and switching.
• They are the building blocks of most of the electronic circuits, especially where audio, current or voltage amplification is required.
• NPN transistors are preferred over PNP transistors for amplification purpose because conduction carried out through mobility of electrons is better than conduction through mobility of holes.

That's all for today. I have tried my best to break down each and everything related to BJTs so you can digest the main concept easily. In case you are unsure or have any question you can ask me in the comment section below. I'd love to help you according to best of my expertise. Feel free to keep us updated with your valuable suggestions, they allow us to give you quality work. Thanks for reading the article.

How to Write a Successful Tech Resume

Hello friends, I hope you all are doing great. In today's tutorial, we are gonna have a look at How to Write a Successful Tech Resume. Technology is one of the most dynamic and rapidly evolving industries in the world. It is one of the largest sectors in the world that is driven by knowledge workers and anything that happens here has a global implication. The ecosystem of tech industry makes it unique in terms of its organizational design and a lot of things work differently here. While a tech firm is a profit maximizing corporate house in essence, but the way it operates is a lot different than a conventional corporate firm. Just like tech firms market themselves differently, their recruitment practices are a bit different too. If you are seeking a job in the tech sector, a conventional resume that might otherwise work well elsewhere, will not work well in the tech sector. Recruiters in tech sector have their own criteria to assess the potential candidate. They look for someone who not only has sound tech knowledge and is up to date with the most current knowledge but has the ability to take challenges and come up with creative solutions. Although a quick Google search will enable you to find a lot of resume samples for tech related jobs, here are a few things you should take care of when writing a tech related resume.

Keep it Short and Relevant

In a conventional corporate job, you would be encouraged to list every single accomplishment that you had in 20 years of your career and you would be tempted to write pages full of information this will not work in the tech industry. Your recruiters in tech are geeks who do not have time to read irrelevant information that is of not much use to them. Know that technology changes rapidly and your skills in FoxPro or GW Basic that you made in the 90s would be totally irrelevant. Your recruiters will be more interested in your skills and knowledge regarding latest industry trends and the most recent achievements. List as many iOS apps that you have developed but skip anything that is obsolete. When your resume is crisp and concise with relevant information, your recruiter will have a reason to give it another look.

Strongly Written Work Portfolio

When you are describing your previous work experiences on your resume, a loosely written list of your duties will not do much favor to you. This is where you have to spend time and write strong descriptions that explain your contribution to the projects you were part of. Use metrics and numbers to demonstrate measurable accomplishments, for example explain a difficult project that you completed in X number of days or a major tech product that you developed and launched. Talk about deadlines, timelines, monetary milestones and leads so that your recruiter can measure you competence in solid numbers. Loosely stating how you are a team player with leadership skills will not do much good for you in the tech world. Try that most of your achievements are as recent as possible so that the recruiters know that you are updated with the market trends.

Web Directory Submission: Does it Work Now?

Hello Friends! I always strive to keep our visitors' needs and demands on the top and try to provide the relevant content that completely aligns with their field of interest. Today, I am going to unlock the details on What is Web Directory Submission? Is it Still Effective for SEO? This is the fifteenth article on the complete SEO series. You can check my previous article on PBN that helps you create a network of blogs pointing to your main blog. Before we move to web directory submission we must be sure What is web directory? It is defined as a directory that is composed of a number of websites with relevant information about websites like site links, what they do and address. Directory submission is a process where you submit your website in a relevant directory that falls under your niche. This process was introduced a long time ago. But does it still work for appearing your blog on the top of search engines? We'll discuss this in this post. Let's dive in and explore the main features of directory submission, how it is used and affect your blog?

What is Directory Submission

Web directory submission is one of the oldest ways to create a backlink. Using this process, you submit your blog or website in a relevant directory with your blog information like a link, address, and what your blog is capable of doing.

• This is considered as an Off-Page SEO which directly or indirectly affects your blog, but you have no direct control over this process. Directory submission doesn't work as it did before.
• Previously, it was effective and useful for link building. Back then, search engines were not smart enough where they gave value to all those sites coming with a high number of backlinks, all the while ignoring if these sites were giving value and providing relevant information to visitors.

Getting a backlink from spammy sites that bring little or no value to your blog is strictly prohibited by the Google, falls under a manipulative process to get a backlink, and holds no value for SEO. Search bots work smartly and quickly catch the sites who try to build backlink by directory submission all the time. But does directory submission still work? That's the main question bothers most of the bloggers, especially who are new to blogging.

• The answer to this question is YES directory submission still works as long as you're doing it correctly. If your blog is new and you want to highlight your content in front of relevant visitors, directory submission still works.
• However, if you only focus on directory submission for building backlinks, it could severely affect your blog overall health and bring more damage than good. Google prefers those sites that come with a diverse backlinking profile.
• Also, it doesn't matter how many backlinks you get but the quality of link does. If these sites from where you get backlinks have the high authority or page ranking, Google will consider your backlink as a vote from the authority site and directs a number of visitors to your blog.

You can check our complete guide of SEO Tutorials where I have listed all posts related to On Page and Off SEO.

How it Works

Directory submission is simple. You just pick a relevant directory that falls under your blog niche and submits your blog information in it. These directories are managed by the editors who follow some rules and regulations before you get accepted by them. Some will accept your blog immediately and some take some time before you get indexed in their directories. It is a matter of time; if you want to get accepted immediately you need to pay. But not all directories work in the same way.

• There are some valuable directories where they only prefer authority sites and demand no money in exchange for a backlink. It takes time to get accepted by these directories. Rest assured, if your blog is well reputed and come with high DA, you'll make a place in these directories, not immediately but eventually.

Normally it takes one month to get a place in those directories but some take 6 months before they accept your blog. They strictly review your site and cross-check based on the terms and conditions they have created for a blog to be indexed. If you meet those terms and conditions, you'll get accepted immediately. As I mentioned earlier, directory submission is not as effective as it was before, but it still influences your blog health, provided you get the backlink from authority sites.

Directory Submission for Business

Directory submission proves to be more effective for businesses than simple blogs or websites. If your blog comes with different online products, then directory submission is a thing you must practice frequently.

• When you are running a business and you get enrolled in a directory, your business comes with a higher chance of appearing in front of relevant visitors.

When users are looking to buy something they prefer to look into directories with the relevant website where they can read the reviews and suggestions about a specific product.

• There are a lot of benefits to getting indexed in directory submission, especially for businesses, but it comes with one drawback unless you're providing a flawless service. If someone reviews bad on the directory site about your product, it can affect your overall reputation.

If you want to run your business like a pro, you need to keep the product quality high that aligns with the demands of the visitors. If someone finds your product low quality that fails to meet their demands, it will force them to review bad about the product that is enough to make a dent in your business reputation.

Top Directories for Website Submission

There are a lot of directories out there you can choose, based on your niche and requirements. The directory you pick must be relevant to your topic and comes with high domain authority. Following are three most popular directories that must be your first priority to get indexed in.

Yelp

If you are running a business, you can't ignore the importance of Yelp directory. This is a platform where visitors interact and share their experiences they get working with specific business. This sets a tone for your business. Positives reviews and feedbacks allow you to appear as a brand, results in attracting a number of customers. Yelp comes with certain rules and regulations that you must pass in order to get indexed in their directory. They don't accept every other business under the sun. Don't rush to get indexed in this directory before the inception of your business. Make sure, you have established a business that can attract a number of visitors where they get what they want. Also, Yelp doesn't work in every country. You can check on their website if your country falls under their eligibility criteria. Once you get enrolled in this directory, make sure to keep the quality of products and services up to the mark. It will help you get a reputation in the early stages of your business. Take an active part in this directory. In case you get a negative review about your product, interact with the customers in a timely manner and help them fix the issue as soon as possible.

• You must provide compensation if your customers undergo bad experience. This can be in the form of a discount for their next visit or any other way based on the nature and capacity of your business.

Your customers are your brand ambassadors. The more you strive to keep the customers' satisfaction on the top, the more you come with a chance of flourishing and growing in your business.

Yahoo

It is another addition to highlight your business in front of a number of people. This is considered as a featured listing directory where only high domain authority websites with quality backlinks can make a place.

• You need to pay to get enrolled in this directory. As mentioned earlier, you don't have to pay for every directory submission, if you do and get caught by the search crawlers, you may get penalized by Google.

But there are some exceptions where Google takes a flexible approach. Google accepts and gives value to the sites enrolled in this directory.

• Don't fall a prey to every other directory submission site which comes with very low eligibility criteria and provides cheap rates for your site to get indexed in it in exchange for a backlink.

DMOZ.org

When it comes to regular web listing, sites like DMOZ.org carry some weight. However, this directory is not as useful as it was before. Also, it gives no guarantee to bring your blog to the top of search results. This directory was created with the intention of uncovering your work in front of a number of people that were deeply interested in your services or products. Facebook turns the things around as it does the same job what this directory used to be doing a long while ago. Now, you can simply create a Facebook page if you want to highlight your work or product in front of targeted people.

Parameters to Consider for Directory Submission

Taking precautions in the early stages of your business can save you a bunch of time. If you really want your business gets off the ground, there are some steps you need to follow. Directory submission, if done in a wrong way, poses a severe threat to your business. Following are some steps you must consider before preparing your blog for directory submission.

Reciprocal Link

Not all web directory sites work in same way. Some work in a reciprocal manner. Before they index your blog on their site, they ask for a reciprocal backlink for their site. This is the least you could do to rank your blog.

• This practice is strictly prohibited by Google where you build backlink profile in a reciprocal manner. Now google becomes more intelligent and strives to bring the most relevant and useful information in front of its visitors.

Directory that Accepts your Blog Right Away

Some directory websites work in a suspicious way and accept your blog right away without reviewing it. If this is the case, you must refrain yourself from submitting your blog on these sites.

• If they are accepting your blog without testing or reviewing it, it means there is something wrong. Every quality website directory follows some strict rules and takes proper measure before they accept your blog.

Manually Audit the Directory

If you are skeptical about the web directory sites and unsure to submit your blog, you can manually audit those sites.

• If you find these directories sites are populated with high authority sites and give backlink based on some following some protocols, then you can submit your blog to these directories.

Alexa Ranking

Alexa ranking is one of the best ways to check site reputation. Go to alexa.com and put the directory link where you want to submit your blog. If it comes with a higher ranking, it gives a green signal that this directory is worth using.

• However, this is not the only way to check the blog authority and reputation. But this is enough to get a clue if directory site gives respect to high authority sites.

Domain Authority

Domain authority is another way to check if the directory website is well reputed and follow some protocols to keep itself higher in the search engine.

• Domain authority is a concept given by Moz. You can go to Moz and check the domain authority of the site you want to submit your blog on. If a website has domain authority around 50, then you hope for submitting your blog on that domain.

Directory Submission in the Eyes of Google

Google was lenient before and valued those sites with a number of backlinks. But soon it discovered giving value to those sites that were unable to fulfill the requirements and demands of visitors was of no use.

• Why would someone come to visit google if they knew the information they got wouldn't be resonating with their field of interest? This made Google force to filter out the sites using spammy way to appear on the top of the search engines and started giving importance to those sites that come with quality content and bring more value to the visitor.

Goole gives value to the sites that are indexed in quality web directories. Getting a backlink from directory submission only is not effective and put your blog in extreme danger.

• Google prefers those sites that come with diverse backlinking where a number of quality sites are linking to your profile.

Conclusion

Getting backlinks solely from directory submission may not be your first priority but you can't ignore the importance of getting backlinks from authority directory sites especially when you run a business. Google gives value to the sites pointed to quality backlinks, and it doesn't matter if they are coming from other blogs or directory submission sites, as long as they are maintaining quality, they are a good fit for your website. And if you are bringing value to the customers, your content will be worth sharing across the web. Make sure, you are not completely relying on directory submission for generating a backlinking profile. Make your backlink profile diverse in nature if you want value and respect from Google. What is your experience with directory submission? Feel free to keep us updated with your valuable opinion and suggestion for creating backlinks. Thanks for reading the article.

Why you should select JLCPCB - An Outstanding PCB Fabrication House

Hey Friends! Hope you are doing great. I am back to give you the daily dose of useful information that helps solve your problems, allowing you to make a better decision. Today, I am going to give you a quick review about one of the best PCB fabrication houses called JLCPCB. If you are hobbyists or a student, you need to connect a number of electronic components together to streamline your project every now and then. Breadboards are ideal for this purpose if you need a temporary solution. When things go complex and you need a permanent solution, breadboards fail to meet your needs and demands. This is where PCB comes into play. The function of PCB board is same as a breadboard i.e. connecting number of components together but it gives a permanent solution to your problems. Instead of fabricating board own their own, some people prefer ordering PCB online. Why? Because it saves their time and helps them focus other important features of a project. There are a lot of PCB fabrication companies out there and most of them come with identical prices in one way or the other. The difference occurs when it comes to quality. Providing quality product while maintaining the prices intact is a real deal where most of the companies lack. They either provide a competitive price or quality product, not both of them together. Forgive me if I'm exaggerating, but that's reality in most of the cases. When quality increases, companies tend to demand more price that is not suitable for most of the people especially when you are a student. Don't worry I've got you covered. You don't need to wrestle your thoughts to find the suitable manufacturer for your PCB fabrication.

JLCPCB - PCB Fabrication House

JLCPCB is a fabrication house that aligns with your need and requirements and delivers exactly what it promises. It comes with every type of PCB solution from single layer to multilayer to complex rigid-flex PCBs. You can pick any board based on your needs and requirements. You can manufacture PCB on your own if you don't get intimidated by playing with chemicals or you need only one or two boards for your projects. Things don't work the same way when you need a lot of boards required to get your project done in less time. You have to rely on other companies that provide a quick solution to your needs. We have personal experience working with this company couple of times. The boards they delivered were perfect where traces were smoothly aligned on the board. It was a while ago when we got our boards and they are still working fine. You can get your Quote here. 

Boards with Thick Traces

Most of the customers are concerned about the nature of traces and materials used for boards, as they have to work on the projects that involve high temperature and pressure where a quality board is needed that can resist high temperature. JLCPCB always takes such things into account and produces boards with thick traces that prove to be ideal for high temperature and pressure. These boards come with a quality of dissipating energy outside the board, helping in retaining the quality of the project they are used in.

Quality Customer Service

One amazing thing that I have discovered about them is their quality customer service. If you think the product you got, doesn't resonate with your demands and nature of the project, you can immediately contact them and ask for the revision of the product. Or if a faulty product is delivered, you'll get a refund with no questions asked within one day.

Gerber File

No need to worry and anticipate what the actual product looks like. They come with an option to upload Gerber file where you can check the board and calculate the number of traces on it. Gerber file truly highlights the features of the board what it actually looks like, minimizing the risk of getting a wrong product that would get you in trouble in future.

Economical Price

Economical price is one of the reasons why you should prefer working with this fabrication house. Some people become skeptical about quality on seeing very low prices on their sites. You don't need to worry about that, this fabrication house is located in China, where labor cost is too low. If you order same product from different countries like UK or US, this would almost double the cost.

Customer Satisfaction

They know very well how to grow and retain the customers. They have 10 years experience in their field and come up with a professional staff that not only provides you quality product but also helps in making the final decision for selecting the ideal board that aligns with your project, so you don't need to come back over and over again.

AOI Ensured

In order to make sure all traces and pads are connected and aligned together, all boards pass through AOI (automated optical inspection). The flying probe test is applied to check the vias of the board, provided boards are two layers or multilayers as single layer boards don't require this test. They have advanced systems covered with quality control where they keep a proper check on the machines and do regular maintenance in order to provide a quality product.

Forum

If you have any question related to your project you can ask in the forum available on their site. The forum is their online community where they keep together people of same interest who take an active part in discussions and provide valuable solutions to your problems. Their professional team is also very active on the forum, and they make sure you don't feel left out in PCB manufacturing process.

Fast Delivery

No need to worry about the delivery time of the board. They take a deep interest when it comes to the quick delivery of the product. However, delivery time is different for different boards, depending on the complexity and nature of the board. Prices are given on their site and you can order as low as $2/10pcs. Yes, you heard me right. And each piece comes with solder mask and silkscreen in order to increase the strength of the board that provides the insulation between the copper layers in case any conductive material touches the board. I'm trying to add one or two negative opinions to make this review unbiased, but the reality is there is not any. You might be thinking I am sugar coating them based on the number of good things about them. I bet you'd be writing same when you get hands-on experience working with them. This is all about JLCPCB - PCB Fabrication House, a quick solution to your problem. If you are unsure or have any question, you can approach me in the comment section below. I'd love to help you according to best of my expertise and skills. Feel free to inform us about your opinion about them. Thanks for reading the article.

LED Blinking using Raspberry Pi 3

Hello friends, I hope you all are doing great. In today's tutorial, we are gonna have a look at LED Blinking using Raspberry Pi 3. It's our first embedded project on Pi 3 and its quite simple. In our previous tutorials on Raspberry Pi 3, we have seen How to install Rasbian on SD Card for Pi 3 and then we have also setup HDMI LCD with Pi 3. So, now our raspberry Pi 3 is ready to program. In today's tutorial, we will interface a single LED with digital Pin of Raspberry Pi and then we will design a simple code in Python which will turn this LE ON and OFF. It will be quite simple and I will guide you step by step, but if you got into any trouble then ask in comments and I will help you out. So, let's get starteed with LEd Blinking using Raspberry Pi 3:

LED Blinking using Raspberry Pi 3

• On our previous tutorials, we have already set up our computer with raspberry Pi 3. If you haven't read those articles then you must go through them first.
• So, here's our final setup as shown in below figure:

• You must have noticed in above figure that we have an extra Bread Board, which was not present in our Previous Setup.
• I have placed an LED on this Bread board and here's its circuit diagram:

• I would recommend you to use Bread Board but if you can manage to connect legs of resistor and LED then that's fine as well. :P
• Here's a close look of this LED placed in Bread Board.

• Now we have successfully designed our simple electronic circuit.
• It's time to start moving towards coding part.
• We are gonna use Python language that's why I am gonna open pre installed tool in raspbian named as Python 3 (IDLE).
• We are gonna use this environment to design our python code.
• So click on your Menu > Programming > Python 3 (IDLE), as shown in below figure:

• Python 3 will open up, so click on File and then New File to create a seperate File for this project, as shown in below figure:

• You can give a name to this New File, as I have give it Blink.py , .py is the extension for python files.
• In this Blink.py, we are gonna write our code, which will blink the LED, here's our code:

• Copy the below code and paste it in your Blink.py file as shown in above figure.

import RPi.GPIO as GPIO
import time

LED = 11 # pin11
print(" ******** LED Blinking using Raspberry Pi 3 ********* ")
print(" **** Designed by www.TheEngineeringProjects.com **** ")
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD) # We are accessing GPIOs according to their physical location
GPIO.setup(LED, GPIO.OUT) # We have set our LED pin mode to output
GPIO.output(LED, GPIO.LOW) # When it will start then LED will be OFF

while True: #Compiler will keep on executing this loop (infinite loop
GPIO.output(LED, GPIO.HIGH) # led on
time.sleep(2) #delay
GPIO.output(LED, GPIO.LOW) # led off
time.sleep(2)

• You can also download this Blink.py file by clicking below button:

[dt_default_button link="https://www.theengineeringprojects.com/RaspberryPi3/LED Blinking using Raspberry Pi 3.rar" button_alignment="default" animation="fadeIn" size="medium" default_btn_bg_color="" bg_hover_color="" text_color="" text_hover_color="" icon="fa fa-chevron-circle-right" icon_align="left"]Download Blink.py File[/dt_default_button]

• When you run this Blink.py File by pressing F5, then your LED will start blinking. Here's the screenshot of LED in ON state:

• So, that's how you can interact with hardware pins of Pi 3.

I hope after following today's tutorial you can quite easily design this LED Blinking using Raspberry Pi 3. If you got into any troubles then ask in comments and I will sort them out. In the next tutorial, we are gonna have a look at How to Create a GUI in Python. Till then Take care and have fun !!! :)