The Engineering Projects

JLCPCB: A Quick PCB Manufacturer - Only PCB Solution You Need

Hi Friends! We are here to help you with valuable information keeping in view of your needs and requirements. This is a platform where you get knowledge related to engineering & technology and anything exhibits technical aspect. Today, I am going to give a quick review of one of the best PCB fabrication houses called JLCPCB. PCB plays an important role in the execution of many projects. A recent surge in an innovative technology has removed the need of joining various electronic components using old methods where you required an end to end wiring to place components together. This is where PCB comes into play.

JLCPCB Fabrication House

If you take a deep interest in the embedded system, more often than not, you need to fabricate the PCB. It is good to fabricate your PCB on your own if you have enough time before the execution of the project. But when you have many projects in place, fabricating PCB by yourself is not a good idea. This is where you look for the fabrication house on which you can trust and expect quality service. Selecting a right PCB fabrication house is kind of tricky and time consuming when you're overwhelmed by lot of information available on the internet. I'd be doing injustice if I wasn't giving an unbiased review about this outstanding PCB fabrication house known as JLCPCB. This is not an exaggeration. This is the result of our personal experience working with them. They are the quick PCB manufacturer and provide top-notch service. Their quality product has forced me to write a quick review about them. If you are unsure and skeptical of where to start the designing process, you can look at this list of Top 10 PCB Design Software.

Best Quality

Everyone is concerned, when it comes to quality. Yes, you wouldn't like to put your whole project at stake for sake of getting the low-quality product. JLCPCB understands the nature and complexity of your project and provides you quality product that resonates with your needs and demands so you keep coming back for what they have to offer.

Live Chat Support

If you are a new customer or returning one, they deal with everyone equally. They help you throughout the whole process i.e. from citing the quotation to the completion of the end product, so you don't feel you are left out in the process. They come with a quick chat support service where you can ask them anything related to your desired product. Make sure you contact them during their business hours. If you are unable to connect them through live chat support service during business hours you can leave them a message at support@jlcpcb.com, they will give you quick response at their earliest. They take out of the box approach to deal with your questions and queries until you feel satisfied.

Quick Quotation

Placing an order is very easy. You don't need to get intimidated by registering or login before you place an order. This quick PCB manufacturer house comes with PCB calculator on their site from where you can put the details of your product and get an instant quote. However, you'll be asked to register and put login details once you are sure and satisfied with the quotation. This saves you a bunch of time and worry, making sure only serious people put their login details who are deeply interested in getting the required product. They are in this PCB fabrication field for 10 years now and retain almost 200,000 customers around the world. This is a big achievement though. No? You decide. You can get a quote from this quick PCB manufacturer here.

Forum

The forum is an important introduction to their website where many professional of the same interest take an active part in the discussion running on their website. If you are unsure or have any question, you can ask in the forum, you'll get an instant reply. They also have a team of professionals who keep your needs and demands on the top, making sure you are completely satisfied before you place an order.

Fast Delivery

Time appears to be very crucial for many projects especially when you have too many projects in place and you need to deliver in time. In this case, you look for the service who delivers within due date. Don't you worry, they have got you covered. They are quick PCB manufacturer and deliver exactly what they promise. However, lead time is different for different orders, based on the nature and complexity of the project. Generally, lead time ranges from 2 business days to 1 weeks week. However, if you are in hurry and require product before the lead time mentioned on their site, you can ask them in advance.

Types of PCB

They have an ability to fabricate any kind of PCB ranging from the single layer, double layer, multilayer, rigid to flexible PCB. They provide you ease of uploading of Gerber file of your product, so you can look and anticipate the whole PCB before it gets delivered to your place. This process refrains you from the risk of getting the wrong product that may cause a problem in the later stage of your project. However, in case you find a faulty product or you feel the product you get, doesn't align with your requirements, you can quickly ask for the replace or refund. They will either replace the product or give your full refund without any question asked.

Covered with Silkscreen and Soldermask

You might be thinking if the finished product is covered with solder mask and silkscreen layer? Yes, it does. The final product you get, contains proper finishing and traces are aligned together in a way that you won't find any broken layers. And the copper layers that are placed on the board are thick and can afford high temperature and pressure. Thick copper layers allow the board to dissipate energy, saving the project from too much heat that can cause problems in the execution process. Rigid-Flex is another type of PCB that is not available quite often but you can order it from this company.

Regular Maintenance

They have recently installed advanced lines, where they take proper measures and keep checking the machines with a regular interval, making sure preventive maintenance is properly maintained and controlled.

Economical Cost

Did I mention you'll get the product at the most economical cost? Yes, that's right. If you order few or in bulk, rest assured, you'll get the product in less price as compared to available in the market. Their low prices don't put you in doubt of getting low quality. They know how to keep the quality and price intact, making sure the product you get, matches with your needs and demands. You'd be thinking why I haven't mentioned any limitation or drawback of their service. Reality is, there is not any. In case, I had found one, I'd be the first person mentioning that at first place. Because we have an experience of getting their service multiple times and they haven't disappointed us once. That's all for today. This is enough to get you started and make a final decision. They are the quick PCB manufacturer and go an extra mile to meet your needs and demands. If you have any question, you can ask me in the comment section below. I'd love to help 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. Thanks for reading the article.

Introduction to 7805

Hey Fellas! We always strive to keep you updated with best and valuable information so you keep coming back for what we have to offer. Today, I am going to uncover the details on the Introduction to 7805. It is a positive voltage regulator used for providing constant output voltage over a wide range of input voltage. Before we move on, you must be clear what is voltage regulation? Voltage regulation is referred as the measure of voltage change between input and output. The IC 7805 does the same thing. It provides constant output voltage when a range of different voltage is applied at the input terminal. This component comes with three terminals called input, ground, and output. This is called positive voltage regulator because it generates positive voltage with respect to the ground terminal. Transistors and voltage regulator IC like 7805 work in a similar way with the intention of providing voltage regulation. I'll discuss each and everything related this integrated circuits, so you get a clear idea what it does, and how it is used over a wide range of applications. Let's dive in and explore what is this about and everything you need to know.

Introduction to 7805

• 7805 is an IC used for voltage regulation and comes in TO-220 version. This component belongs to 78xx series where xx defines the output voltage it generates.
• Voltage fluctuation is a common practice during the execution of many electronic projects. This component overcomes and prevents this voltage fluctuation by providing a constant output voltage at the output terminal.
• The best part is that it doesn't require any additional components to set output voltage.
• It is a compact IC that comes with a built-in protection circuit that avoids the circuits from too much heating, making it suitable for circuits drawing high current.
• The input voltage range applied to the input terminals of this IC varies from 7 V to 18 V (in some cases 7 to 35 V), resulting in the generation of constant output voltage around 5 V.
• You can see, there is a huge difference between input voltage and the output voltage that gets regulated. This difference is discharged as heat. The surge of heat generation can damage the device and affect the overall project performance.
• There are two ways to overcome this heat generation i.e. you can use a heat sink that is widely used for heat dissipation OR you can limit the input current 2 to 3 V above the regulated voltage at the output terminal. For example, you'll get 5 V at the output terminal, so it is suitable to limit input voltage within 7 or 8 V.

• Heat sink comes in different sizes based on the amount of heat that is required to disperse. It is advised to calculate the size of heat sink before you put your voltage regulator in operation.
• With the addition of heat sink, this IC can control output current at around 1.0 A.
• This voltage regulator is an ideal choice for the applications where safe area compensation, thermal shutdown, and current limiting is required.
• This device is designed with the purpose of getting constant output voltage, however, it can be coupled with external components with the intention of generating desired voltage and current.
• This IC comes with an accurate circuit which generates constant voltage so no capacitors are required to produce smooth output, however, it is advised to place 10µF capacitors in the input and output terminal to remain in the safer side.

Pinout of 7805

• Following figure shows the pinout of this voltage regulator.

• Pin 1 shows the input voltage applied to this regulator which ranges between 7 to 18 V.
• Pin 2 shows the ground terminal. Voltage regulator generates positive voltage with respect to the ground terminal.
• Pin 3 shows the output terminal where regulated voltage is obtained. Regulated voltage shows the tolerance between 1.5 % to 2 %.
• This regulator has a capacity of controlling output current around 1 A.
• It shows a voltage dropout around 2 V. It is advised to provide minimum 7 V at the input terminal in order to obtain exact 5 V at the output terminal.

Absolute Maximum Ratings

• Following figure shows the absolute maximum ratings of 7805.

• These are the stress ratings, which if exceed from absolute maximum ratings, can damage the device severely.
• Before you place this regulator in the circuit, make sure it undergoes and exhibits same stress ratings as defined by the manufacturer.
• Similarly, it these stress ratings are applied for a maximum period of time above the normal operating conditions, they can affect the device reliability.
• These ratings are obtained with a storage temperature range at around 150 °C.
• This IC exhibits a thermal resistance around 5 °C/W which is the resistance in the heat flow.

Applications

This voltage regulator is used over a wide range of applications. Following are some main applications of this regulator.

• Used in a circuit where a constant voltage is required.
• It is used in a phone charger and portable CD player.
• UPS power supply circuit and remote control extension make use of this regulator.
• This regulator is widely used where internal circuit current limiting is required.
• Safe area compensation is another advantage obtained from this regulator.
• This regulator is mainly used for generating constant voltage output, but it can be customized to use for the required current and voltage at the output.
• It is an ideal choice for the applications which support current around 1.0 A to 1.5 A which cannot be obtained without proper heat sinking.
• Safe operating area protection and thermal shutdown make it suitable for many applications involving high temperature and pressure.

That's all for today. I hope you have found this article useful. If 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 in any way I can. Keep your feedback and suggestions coming. They allow us to provide you quality work that aligns with your needs and demands. Thanks for reading the article.

Introduction to 2n3792

Hey Guys! Hope you are doing great. Transistors are the fundamental parts of the recent electronic devices. They are available in two types i.e. NPN and PNP transistors. Based on the technical aspect and utilization, both types come with different benefits and advantages. Today, I am going to discuss the details on the Introduction to 2n3792. It is a PNP (positive-negative-positive) silicon bipolar power transistor mainly used for amplification and medium speed switching. It is manufactured using epitaxial planer process and comes in TO-3 casing. I'll cover each and everything related to this transistor so you don't need to go anywhere and find all information in one place. Let's explore what is this about, its main applications and everything you need to know.

Introduction to 2n3792

• The 2n3792 is a PNP bipolar transistor which is mainly used for amplification and medium speed switching applications.
• It consists of three layers where one N-doped layer is housed between two P-doped layers.
• It has three terminals called emitter, base, and collector. All these terminals are different in terms of their doping concentrations. The emitter is highly doped as compared to base and collector terminals.
• In this transistor, base-emitter is more positive with respect to base and collector. While negative biased voltage is applied at the base terminal.
• It is a current controlled device where small current at the base side is used to control the large current at other terminals.

• In this PNP transistor, current directions and voltage polarities will be reversed as compared to NPN transistors.
• It works in a similar way to NPN transistor i.e. both are used for amplification purpose where small current at the base side is used to control the large current at the emitter and collector side, however, there is one exception, unlike NPN transistor, holes are diffused through base from the emitter and collected by the collector.
• This PNP transistor is rarely used for amplification purpose because conduction carried out by the movement of electrons is considered more valuable than conduction carried out by the movement of holes.

Pinout of 2n3792

• Following figure shows the pinout of this PNP transistor. It consists of three terminals.

1. Base 2. Emitter 3. Collector 

• Voltage is applied at the base terminal, which draws small current.
• The output current obtained at the collector terminal is highly dependent on the voltage applied at the base terminal. This process is used for amplification purpose.

Circuits Diagram of 2n3792

• Following figure shows the circuit diagram of 2n3792.

• Current at the emitter terminal is equal to the sum of current at the base and collector side. The emitter is highly doped so it exhibits more current as compared to other terminals.
• In this transistor current direction is reversed as compared to NPN transistor. In this case, current flows from collector to emitter.
• Voltage polarities are also reversed. Negatively biased voltage is applied at the base terminal in order to initiate holes reaction which is then used to control the large current at the other terminals.
• As the name suggests, this is a bipolar junction transistor where conduction is carried out by both charge carriers i.e. electrons and holes, but holes are majority charge carriers in this case. While electrons are majority charge carriers in NPN transistors.

Absolute Maximum Ratings of the 2n3792

• Following figure shows the absolute maximum rating of the 2n3792.

• These are the stress ratings that play an important role in the selection of this transistor for electronic circuits.
• If stress ratings exceed the absolute maximum ratings, they can damage the device.
• Similarly, if these ratings are applied for the maximum period of time above normal operating conditions, they can effect the reliability of the transistor. Before you pick this transistor for your project, make sure, it exhibits and undergoes same ratings as defined by the manufacturer.
• Power dissipation is 150 W and these absolute maximum ratings are taken at the absolute junction temperature around 200 ºC.
• Thermal resistance is 1.17 ºC/W which is the measure of resistance to the heat flow.

Applications

• This transistor is used for medium speed switching applications.
• It is also used for an amplification purpose.

That’s all for today. I hope you have found this article useful. If you are unsure or have any question, you can ask me in the comment section below. Your suggestions and feedback will be highly appreciated, they allow us to provide you quality work that resonates with your needs and expectations. Thanks for reading the article.

Introduction to 2n4123

Hey Guys! I am back to give you a daily dose of information so you can excel and grow in your relevant field and keep coming back for what we have to offer. If you are a hobbyist or student, you require a transistor for the execution of your project every now and then. Today, I am going to unlock the details on the Introduction to 2n4123. It is an NPN (negative-positive-negative) general purpose transistor which is mainly used for the amplification and switching purpose where collector current around 100mA is required. It is a semiconductor device mainly composed of silicon and comes with three terminals where a voltage applied to the one pair of terminals is used to control the current at the other pair of terminals. I'll break down each and everything related to this transistor in easy steps so you can grab the main concept easily. Let's dive in.

Introduction to 2n4123

• The 2n4123 is an NPN bipolar junction transistor mainly used for amplification and switching purpose, especially where collector current of 100mA is required.
• This transistor comes with three terminals called emitter, base, and collector that are used for the external connection with the electronic circuits.
• All these three terminals are different in terms of doping concentration. Emitter terminal is highly doped as compared to base and collector terminals.
• The base terminal is lightly doped which controls the number of electrons. Collector terminal is moderately doped which collects the number of electrons from the base terminal.
• Actually, NPN transistor is a combination of diodes joining back to back.

• This NPN transistor is termed as a current controlled device which is different than JFET that is voltage controlled device.
• One P-doped semiconductor layer is housed between the other two N-doped layers. The P-doped layer represents the base terminal while other two layers represent emitter and collector respectively.
• When a voltage is applied at the base terminal, it draws small current which is then used to control large current at the emitter and collector terminals.
• This process is used for amplification purpose where small current controls the large current.
• An output current obtained at the collector terminal is highly dependent on the intensity of voltage applied at the base terminal.
• This transistor operates in forward biased mode. If a transistor is not forward biased, collector current will be zero, no matter how much voltage is applied at the base terminal.

2n4123 Pinout

Following figure shows the pinout of this NPN transistor which mainly consists of three terminals. 1. Emitter 2. Base 3. Collector 

• When a voltage is applied at the base terminal, it triggers the electron reaction, resulting in the diffusion of electrons from the base to collector terminal.
• This movement of electrons is highly dependent on the voltage applied at the base terminal.
• The number of electrons diffused into the base terminal from the emitter is greater than the number of holes diffused into the emitter region.
• When the electron enters the base terminal it combines with the hole inside the base terminal where resulting pair disappears.
• The base terminal cannot control all electrons diffused into it from the emitter terminal, resulting in the transfer of electrons from the base to collector terminal.

Circuit Diagram of 2n4123

• Following figure shows the circuit diagram of the 2n4123.

• Current at the emitter terminal is equal to the sum of base and collector current because doping concentration of emitter is more than other terminals.
• The base is more positive with respect to the emitter which makes it an ideal choice for controlling the number of electrons.
• There are two current gain factors that are mostly used to determine the characteristics of the transistor. One is common-emitter current gain which is a ratio between collector current and base current. This is called Beta and denoted by ß.
• Its value ranges between 20 to 1000, however, the standard value is taken as 200.
• Beta is a ratio between two currents so it exhibits no unit. It is also known as amplification factor and determines the amount of current being amplified.
• Another current gain is common-base current gain which is a ratio between collector current and emitter current. It is called alpha and denoted by a. Alpha value ranges between 0.95 to 0.99, however, most of the time its value is taken as unity.
• It is important to note that if we interchange emitter and collector, then the transistor will become reverse biased and these current gains show low value as compared to values taken from forward biased transistor.
• In this NPN transistor, electrons are main charge carriers, which is different than PNP transistor where holes are major charge carriers.

Absolute Maximum Ratings of 2n4123

• Following figure shows the absolute maximum ratings of this transistor.

• These are the stress ratings that must be controlled before you place this component in the electronic circuit.
• If these stress ratings are exceeded from the absolute maximum ratings, they can damage the device at large, which ultimately affect the performance of the project.
• Similarly, if these stress ratings are applied for a maximum period of time above normal operating conditions, they can affect the device reliability.
• These ratings are determined on the basis of the maximum junction temperature of 150 °C.

Applications

• This NPN transistor is mainly used for general purpose amplification.
• Switching applications involve this NPN transistor where collector current around 100mA is required.

That's all for today. I hope you have found this article useful. If you are unsure or have any question, you can ask me in the comment section below. I'd love to help you in any way I can. Keep your suggestions coming. Your valuable suggestions and feedback keep us busy providing you quality work that resonates with your field of interest. Thanks for reading the article.

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.

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.

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.

Introduction to 2n6547

Hey Fellas! Hope you are doing great and having fun in your lives. We always try to keep you updated with useful information that resonates with your needs and expectations so you can grow and excel in your relevant field. I am back to give you a daily dose of useful information that may help you resolve your queries and problems related to engineering and technology field. Today, I am going to unlock the details on the Introduction to 2n6547. It is an NPN bipolar junction transistor that comes with high voltage and current capability and fast switching speed, mainly used in switched mode power supplies and flyback and forward single transistor low power converters. I'll try to cover each and everything related to this NPN transistor, so you don't need to go anywhere and find all information in one place. Let's dive in and explore what is this about and what are its main applications?

Introduction to 2n6547

• 2n6547 is an NPN bipolar junction transistor that comes with high voltage and current capability and fast switching speed, mainly used in switched mode power supplies and flyback and forward single transistor low power converters.
• It comes in a TO-3 metal case and is an ideal choice for industrial and switching applications from single and three-phase mains.
• This NPN transistor is a bipolar junction transistor where conduction is carried out by the movement of both charge carriers, i.e electrons, and holes, however, main charge carriers are electrons.
• It mainly consists of three terminals called emitter, base, and collector.

• All three terminals are different in terms of size and doping concentration. An emitter is highly doped as compared to base and collector while a base is lightly doped.
• When a voltage is applied at the base terminals, it triggers the electron reaction which draws current.
• Small base current is used to control large current at the emitter and collector side.
• Electrons play an important role in maintaining the bridge between emitter and collector of this transistor.

2n6547 Pinout

Following figure shows the pinout of 2n6547

• This transistor is basically a current operated device where small current at the base side is used to control the large current at the emitter and collector side.
• The ability of base current to control large currents is used for amplification purpose.
• This transistor is a bipolar current controlled device which is different than JFET that is a unipolar voltage controlled device.

Circuit Symbol of 2n6547

Following figure shows the circuit symbol of 2n6547.

• The base of the transistor is more positive than the emitter while the voltage at the collector side is more than base voltage.
• Current at the emitter side is equal to the sum of current at the base and collector side.
• As it is an NPN transistor, it sources the base current to the transistor.
• The measure of a number of electrons that pass from base to collector is called transistor efficiency.
• The base is lightly doped and the emitter is heavily doped that will allow the electron to move from the emitter to base more than it will allow the holes from base to emitter.
• Transistors always operate in forward biased mode. If we interchange emitter and collector and makes it reverse biased, then the value of alpha and beta will be much lesser than they will be in forward biased mode.
• Forward current gain is represented by beta ß, which is an important factor for amplification purpose. It is a ratio between collector current and base current and its value ranges between 20 to 1000, however, its standard value is 200.
• Current gain is another important factor which is a ratio between collector current to the emitter current and it is denoted by alpha a. Value of alpha ranges between 0.95 to 0.99, however, most of the times alpha value is considered as a unity.

Absolute Maximum Ratings of 2n6547

Following figure shows the absolute maximum ratings of 2n6547.

• It is important to note that these are the stress ratings. If these stress ratings are exceeded above absolute maximum ratings, they can damage the device at large and affect the quality of the component.
• If these stresses are applied for a maximum period of time, they can affect the reliability of the component.
• Take strict measures and follow international protocols while dealing with this components, otherwise, they can affect the project you are picking this component for.

Applications

• It is mainly used in switched mode power supplies.
• Flyback and forward single transistor low power converters make use of this device as it exhibits high voltage and current capability.
• This transistor is an ideal choice for switch mode applications ranges between 115 to 220 V.
• Inductive circuits where fall time plays an important role, are equipped with this transistor.
• For industrial purpose, it is used for motor drive control.

That's all for today. This transistor comes with electrons as majority carriers, different than PNP transistor that comes with holes as majority carriers. I hope you have found this article useful. However, if still you feel skeptical 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. Keep up updated with your valuable feedback and suggestions, as they allow us to give you quality work that meets your requirements. Thanks for reading the article. Stay Tuned!