The Engineering Projects

Simplest LM386 Audio Amplifier in Proteus

Hey Learners, welcome to another exciting tutorial about electronics. We are talking about an audio amplifier using LM386. This is a very simple IC that we are going to used for the amplification of the audio signals. We shall go through the core postulation about the topic and then work on the practical implementation of the experiment. Just have a look at the topics of discussion:

1. Introduction to LM386 Audio Amplifier.
2. Components of LM386 Audio amplifier.
3. LM3386 Audio Amplifier Working.
4. Simulation of the LM386 Audio Amplifier Circuit in Proteus.

In addition, you will find interesting information in the DID YOU KNOW sections.

Introduction to LM386 Audio Amplifier

Audio signals play important role in many devices. These signals are used to regulate the life of the community in many ways. These signals, when required, are amplified by some means to use them more effectively and efficiently. Many devices can do this task. Yet, at the present time, we are going to discuss LM386 Audio Amplifier. Let's have its definition:

• "The LM386 audio frequency Amplifiers are the types of low power audio amplifiers used commonly in small amplifier systems and can be run on even a 9V battery."

The input signals once pass through the LM386, are amplified and the user senses a loud sound as compare to the input signal. This type of amplification is really important in the circuits where a signal is required to show the completion of the task, requirement of the involvement of the user or an error in the circuits.

Components of the circuit of LM386 Audio Amplifier

In this article, we're using the very simple circuit of LM386 Audio Amplifier to show the easy but understanding hypothesis of the topic. This circuit consists of capacitors, audio signals, LM386 IC, power source and speaker, out of which, we have to discuss the LM386 IC, Audio signals and speaker.

LM386 IC

The LM386 is a versatile chip that can easily be used in many kinds of circuits. The IC  runs no low voltage, therefore it is a very common yet power operational amplifier that is used even in DIY guitar pre-amplifiers. If we look at the basic definition of LM386 then we find:

"The LM386 is an 8-pin Dual inline integrated circuit that can work on very low voltage and when connected with some simple components can be used as an operational amplifier in a large number of amplifying circuits."

The power intake and efficiency depends totally upon the models of the LM386. Basically, there are three models of aLM386 IC as mentioned below:

Number of Pin	Name of pin
1	Gain
2	Negative input
3	Positive Input
4	Ground
5	Gain
6	Bypass
7	Input power
8	Output of IC

Being an op-amp, the LM386 has a very basic task. The IC gets the power from its input terminals and using its circuitry, it amplifies the power output signal on the rate of tens, hundreds, thousands and so on. The total output purely depends upon the input and the model of LM386.

Speaker

The speakers are the devices that takes the audio signals and convert them into voice. This conversion is done by the special mechanism of speaker. In this experiment, the output will me hear with the help of this speaker.

Variable Resistor

As the name describes, the variable resistor is the special device that is capable of changing the value of resistance according to the requirement of the user. The + and - terminal of variable resistor are used to increase and decrease the resistance respectively. In this way, the input audio signals can be controlled.

Working of LM386 Audio Amplifier

1. The working of the LM386 Audio Amplifier starts with the audio signal generation of audio generator.
2. These signals passes through the capacitor that regulates these signals and then pass them to the LM386.
3. The IC inputs these signals, the pin 6 of the LM386 is connected with the DC Source hence it powers it up. The IC now amplify the audio signals.
4. From pin 5 of the IC, the amplified audio signals are generated. Meanwhile, the resistor and capacitor regulates the signal so that the user may sense these signals in the right sequence of waves.
5. Finally, the speaker takes these signals as input and convert it in the form of sound so that the user can hear it easily.

Procedure to simulate the LM386 in Proteus ISIS

By availing all the information given above, let's simulate the circuit in Proteus ISIS. Just apply the instructions given below:

Material Required

1. LM386 IC
2. Resistor
3. Capacitor
4. POT HG
5. Speaker
6. Ground Terminal
7. Audio device

• Start your Proteus ISIS.
• create a new Project.
• Click on P button.
• Choose 1st five components mentioned in the list given above.
• Arrange all the components on the working area by following the image given next:

• Go to Terminal Mode from the left side of your screen and choose ground. Now, set it just below the circuit.
• Go to Generator mode>choose audio and set it just on left side of arrangement.

• Double click the audio probe>brows>upload this file.
• [audio wav="https://www.theengineeringprojects.com/wp-content/uploads/2021/06/file_example_WAV_1MG.wav"][/audio]
• Change the values of the components as described in the following table :

Component	Value
C1	1nF
C2	100F
C3	1uF
C4	47nF
C5	47 nF
C6	220uF
R1	10 ohm
R2	10 ohm
DC Power Supply	9V

 

• Once all the values are changes, just go to virtual Instrument mode and select the oscilloscope above the components.
• At this time, join the components with the help of connecting wires.

•  Hit the Play button with your mouse and simulate the circuit.
• Change the values of the voltages of terminals and current through the nobs to get the visible wavelengths.

one can see clearly that the output signal(blue waves) are more amplifier and strong than the input signals (Yellow waves).

Conclusion of experiment

The LM386 is the IC that can be used to amplify the audio signals. The input frequency and thus the volume of the sound amplifies and we can hear the loud sound. One can change the intensity of sound by using the active variable resistor.

RC Electronic Circuits Simulation in Proteus ISIS

Hello friends! Welcome to the Engineering components. Today, We are talking about the very common topic of electronic devices. In this tutorial, we'll pick very common components and learn about their role in circuits. If you are a beginner in the world of electronics, you must read this article till the end because we'll learn all the things from scratch till the completion of the circuit. In this article, you will learn:

1. Introduction to electronic circuits
2. Categories of electronic circuits.
3. Introduction to Resistor and Capacitor.
4. What are RC Circuits?
5. Simulation of R Circuits in Proteus ISIS.

Let's look at the description.

Introduction to Electronic Circuits

We come across many circuits in our daily lives, some of them are electrical circuits and some are electronic circuits. There are many differences between them but the main difference is, that electrical circuits do not have decision-making capacity whilst electronic circuits do have this ability. In electronic circuits, we power up the components with the mean power source and get the output. Hence we may define the electronic circuits as:

• "The electronic circuits are the types of circuits in which the individual electronic components are used that are connected to the power source with the help of wires so that the current can pass through the components."

The electronic circuits are also called discrete circuits because they are somehow, opposite to the integrated circuits. Most of the circuits use a combination of electrical and electronic circuits.

Categories of Electronic components

As we know, electronic components are used in many ways. For convenience, we divide the electronic components into categories. These are categories into two main sections:

1. Active Components.
2. Passive components.

The main focus of this article is passive components. The passive components include Capacitor, Resistor and Inductor. These are symbolized as C, R and L respectively. We'll learn about the first two of them today.

Introduction to Resistor and capacitor In electronic circuits

The Resistor and capacitor may be said to be the backbone of thousands of electronic circuits. To design a circuit, one should have a clear concept of these components. So, Let's have their introductions:

Resistor in Electronic Circuits

As the name implies, the resistor shows the resistance for the current in the circuit. It has a tube-like shape that has a molded figure and has a wire at the start and end. One may define the resistor as:

• The resistor is a passive, bi-terminal electrical component that is used in the circuit to have the electrical resistance in the current. When we use it in electronic circuits, it reduces the sudden current flow in the circuits, biases the active elements, divides the voltages in the circuit and performs such other tasks.

Current is the flow of electrons, this flow should be resisted by some mean, so that the components used in the circuit will be safe from damage. To control this opposition, one must have a clear idea about the resistance. The resistance is the measure of the property of the resistor to oppose the current in a circuit. The resistance of the resistor is symbolized by the strip of different colors. Each color has a meaning of different value.

Capacitor in Electronic Circuits

The capacitor works like a battery. The body of the capacitor is so simple and easy to understand, yet plays an important role in many types of circuits. The introduction of Capacitor is given next:

• The capacitor is an electrical component consists of two metallic plates and two wires connected with two plates that store energy passes through it in the form of an electrostatic field in between its two metallic plates. Its body is packed in an envelope.

As you can see in the picture, capacitors are manufactured in the form of a tube-like shape with two wires that are used to connect within the circuit. The capacitors are made in a variety of ranges according to their role in the circuit.

RC Electronic Circuits

As we know the Resistor is denoted as R and the capacitor is denoted by C. The RC circuits are the simple and easy circuits to understand.  We introduce the RC Electronic circuits as:

"The RC Circuits are the Resistor-Capacitor circuit in that consist of only resistor and capacitor as passive components of capacitor and these are connected with the current or voltage source according to the type of circuit."

One should keep in mind that we are talking about the category of passive components right now. Otherwise, some other components such as the power generating component are also used in the circuit. The are two categories of RC Circuits mentioned next:

1. RC Series circuit.
2. RC Parallel circuit.

RC Series circuits are the ones in which the resistor and capacitors are connected in series whereas, when we talk about the RC Parallel circuit, the R and C are connected in parallel to each other. RC circuits are also called the filter circuit or network circuit because many RC circuits are used to filter the unwanted frequencies of signals from the circuit and keep only the required ones. The RC Circuits are further classified on the basis of the number of components used in the circuit. The circuit is called the first-ordered RC Circuit if it contains only one resistor and one capacitor. Similarly, if it has two resistors and capacitors then the circuit is called the second ordered RC Circuit. To have a clear idea about the circuit, design it on the Proteus.

RC Electronic circuits in Proteus ISIS

To experiment, just follow the steps given next:

Required Components

1. Resistor
2. Capacitor
3. Battery
4. Connecting wires

Procedure

• Start your Proteus software.
• Click on the "P" button and choose the required components one by one.
• Arrange these components in the working area.
• Connect the components with connecting wires.
• Play the circuit with the play button present on the lower-left corner of the screen.

This image shows two types of circuits. The upper circuit is the RC Series circuit and the lower circuit is the RC Parallel circuit. Hence today, we learned about the introduction of Electronic circuits, we saw what are RC circuits, their components and their types depending upon different parameters. We also simulated the circuits in Proteus.

Pure Sine Wave Inverter using 555 Timer in Proteus.

Hi Mentees! Welcome to another electronic tutorial about the 555 Timers. We are working on Proteus and in the present experiment, we'll design the circuit of Pure Sine Wave Inverter. Inverters are the opposite devices to rectifiers. We'll show you the meaning of this sentence in action Yet, before experimentation, we have to learn some predominant concepts about the experiment. So, We'll go through the following topics:

1. Introduction to Pure Sine Wave Inverter.
2. Components used in the circuit of Pure Sine Wave Inverter.
3. Working of the circuit of sine wave inverter.
4. Circuit simulation of pure sine wave inverter in Proteus.

Introduction to Pure Sine Wave Inverter

In electronics, we examine the output of devices in the form of waves. Basically, there are four types of waves including sine wave, sawtooth wave, square wave and triangular wave. The title of the circuit we are discussing today consist of two main concepts:

1. Sine Wave
2. Inverter

Let's recall them one after the other.

• Sine Wave: The sine wave is a mathematical curve that is a smooth, s-shaped, periodic, continuous wave and is described as the graph of sin function indicated by Y=sin x.

The sine waves are used in Mathematics, physics, engineering, signal processing and other related waves. In Electronics, the sine wave indicates the AC.

• Inverter: Inverters are the electronic devices that are used to convert the DC into AC. We can say, Inverters are the opposite circuits of rectifiers. The purpose of this inverter is the same.

Hence, when we combine these concepts, we get the following definition of Pure Sine Wave Inverter:

• "The Pure Sine Wave Inverter is a circuit that takes the input in the form of DC and gives output as AC. It is used to run any type of instruments designed to run on smooth sine wave output."

We can make the circuit with the many methods, out of which two are:

1. Pure Sine Wave inverter through MOSFET.
2. Pure Sine Wave Inverter through 555 Timers IC.

The focus of this article is the 2nd type. So let's look at its circuit.

Circuit of Pure Sine Wave Inverter using 555 Timer

If you understand the working of its components, the circuit of the sine wave inverter is quite simple. It consists of some simple electronic components that every engineer uses many times. But out of them, 555 Timer and Transformer should be discussed here.

555 Timer

The 555 Timer is a great integrated circuit. It is used in thousands of circuits that have the requirement of pulses with uniform length. It is an 8 pin integrated circuit that may be used in three modes. In this tutorial, we'll use the 555 Timer in Astable Mode.

Transformer

A transformer is a passive electronic device that is used to transfer electrical energy from one source to another by the mean of electromagnetic induction. The main purpose of the transformer is to change the level of the input current (high or low) to the output current. The circuit of Pure Sine Wave Inverter is designed so, we provide the 12V DC as input and get the 240V AC as output. In addition to these, we will use Inductor, diode, capacitor, resistor and power source in our circuit.

Working of Pure Sine Wave Inverter using 555 Timers

• The working of the Pure Sine Wave Inverter starts when the 12 volts DC is applied to the components.
• These 12 volts enter the 555 Timer through pin 3 of the 555 timer that is in the Astable Mode. Due to this Mode, the 555 timer produces a single uniform pulse that is fed into the inductor.
• Every time, when a new pulse enters the inductor, it stores the energy in the form of an electromagnet. In the time t, when this energy is fully discharged through the inductor, its signs of induction change. After that, a new pulse enters the inductor and this process goes on. This energy passes through the resistor and finally fed into the transformer.
• In our case, the transformer is stepped high and it gives us the output of 240V AC. One can check this using AC Voltmeter.
• The diode connected to pin 7 of 555 Timer passes the current in only one direction (because it is a diode) and sends this pulse to the transformer by the mean of a capacitor for a steady pulse.

Simulation of Pure Sine Wave Inverter in Proteus

Using all the concepts discussed above, let's get started with the simulation of the circuit by following the simple steps.

Required Devices

1. 555 Timer
2. Vsource (DC power source)
3. Diode
4. Capacitor
5. Inductor
6. Transformer
7. Resistor
8. Connecting Wires
9. Ground Terminal

Circuit Simulation of Pure Sine Wave Inverter

• Excite your Proteus simulator.
• Start a new Project
• Tap to the "P" button of the screen and choose 1st seven devices one after the other from the list of required devices.
• Arrange all the devices on the screen by following the image given below:

• Left click on the screen>Go to Place> Terminal>Ground and set it just below the circuit.
• Change the Values of the devices according to the table given next:

  Components	Values
  R1	1KR
  R2	1KR
  R3	0.02KR
  C1	1nF
  C2	100nF
  C3	100uF
  Inductor	1mH
  Transformer	Primary= 1H, Secondary= 2000H

• Go to Instruments>Oscilloscope and set it at the output side.
• Connect terminal A with
• Now connect all the components carefully with the connecting wires.
• Click on the Play button just at the lower-left corner of the screen and start the simulation.

• You will find the Sine Wave Inversion on the output screen of the Oscilloscope.

Truss, in the present article, we saw the introduction of Pure Sine Wave Inverter, Look at its devices and components, saw the working of the whole circuit and learned to design the circuit in the Proteus practically. We hope you learned well.

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

Hello friends, I hope you all are happy, healthy, and, content. Today, our discussion is all about "Diodes". 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. You might have read a lot about diodes in physics, in today's discussion we would be moving step by step into the pool of diodes from definition to working of diodes, their types, and then lastly its applications. Let's get started!

Diode Definition

First things first, Let's define diode,

• A diode is a basic discreet electronic component made up of semiconductor material, used in electronic circuits, which allows unidirectional current to flow through it, i.e it only conducts current in one direction.
• You must be thinking, how is it possible for a device to conduct electricity in only one direction only, even when it has two terminals?

• The answer lies in making of a diode, a diode has zero resistance in one direction, meanwhile, the other direction has infinite resistance, hence maintaining the flow in only one direction hindering the flow in other direction, but keep one thing in mind, its an ideal case, otherwise a little bit of current flow is always there and ideal cases do not exist!
• A diode can act as a conductor and as an insulator as well. When the diode is reverse biased it acts as an insulator meanwhile when a diode is forward biased, it acts as a conductor.
• Diodes are mainly made up of two famous semiconductors silicon and Germanium.
• There are several different types of a diode, make of each one differs according to its function and the way it transmits current, don't worry we are going to have a detailed account of it soon.

Diode symbol

• The above symbol represents a diode, it's the symbol for a basic diode, let me clear one thing for you, there are several different types of diodes that we would be studying next and each one is represented with a different symbol accordingly. So, do not doubt yourself when you see a slightly different one!
• You can observe two ends or two terminals labeled as cathode and anode respectively.
• The Arrowhead represents the anode and direction of current flow.
• The other end is the cathode represented as a line attached to the terminal vertex of the triangle representing the anode.

History of Diode

Here is a brief account of the history of diodes, a little touch-up hurts no one!

• So, the History of diodes dates back to 1900 when the thermionic diodes and semiconductor diodes were made for radio.
• Vacuum tube diodes were the trendiest items of early 1950 being used and altered by several scientists through different experiments such as Fredrick Guthrie and Thomas Edison.
• Fleming valve was the first recognized diode of its age with all the elements present in a diode in the true sense.
• In world war ll, crystal diodes and Crystal rectifiers were used intensively in radar systems which led to extreme usage and development in the diode world, all thanks to their wide window of utility.

Working and Construction of Diode

In order to understand the working of a diode, let us first discuss its basic structure, how would you understand the working until unless you understand the make and build of a thing!

The basic structure of a Diode

• A basic diode is made up of a semiconductor, a p-type semiconductor and an n-type semiconductor joined together. Do you have a basic idea of semiconductors? Semiconductors are materials that have properties lying within the spectrum of metals and nonmetals, you can read our detailed article on the periodic table if you want to know more about the elements and their respective properties.
• Anyhow, we were talking about semiconductors, semiconductors are of two types, Intrinsic semiconductors, and extrinsic semiconductors.
• Intrinsic semiconductors are pure semiconductors without any additional impurity. They include silicon and germanium.
• Extrinsic semiconductors are the ones with doping, don't worry we are about to discuss it next.
• I hope you have a general idea about p-type and n-type semiconductors, if not, we have got you covered. Read the next section for details;

Doping in Semiconductors

To understand p-type and n-type semiconductors, you must be aware of the concept of Doping. We can define doping as; Doping is the intentional addition of impurities into an intrinsic semiconductor. It changes the physical, electrical, and optical characteristics of that very intrinsic semiconductor.

1. p-type semiconductors

• A p-type semiconductor is made by doping i.e adding an impurity which is an electron acceptor by nature into the semiconductor i.e gallium and boron are added to the silicon, turning it into a p-type semiconductor.
• You must be thinking about why they are called p-type semiconductors? Let me tell you, The name p-type is given due to the presence of a positive charge on the semiconductor.
• The p-type semiconductor contains a majority of holes and a minority of electrons.

2. n-type semiconductors

• The n-type semiconductor is made by doping the semiconductor with an electron donor element.
• The n-type semiconductor has a majority of electrons and a minority of holes.
• The name n-type is given due to the negative charge of electrons present in the semiconductor, you knew that already, or you didn't?
• Arsenic and phosphorus are used for the doping of silicone making it a n-type semiconductor.

Now we are done with the basics of n-type and p-type semiconductors, let us discuss their utility in making a semiconductor diode. The following section includes a breakdown of components and concepts lying in the scope of diodes.

PN junction

• Our discussion would be incomplete without the PN junction, can you think of a diode without it? Yes, there are a few exceptions but typical ones necessarily have a PN junction.
• As I have told you earlier semiconductor diodes are made up of n and p-type semiconductor materials joined together to make a diode.
• The merger of these two materials is responsible for the making of PN junction made between the contact point of two materials.
• After the formation of the PN junction, the process of diffusion takes place, we would be discussing it next, don't worry!

Depletion Region

• There is a considerable difference between the amount of holes and electrons on both sides. If you know about the simple concept of diffusion, a particle moves from the area of higher concentration to the area of lower concentration and vice versa, same happens here, the holes from the p side move to the n side of the diode.
• Meanwhile, electrons move from the n side where they are higher in concentration to the p side where they are lower in concentration.
• This movement of electrons and holes generate a diffusion current leading to the formation of an immobile layer of positive and negative ion on the PN Junction, this layer is called depletion region.
• Now you must be thinking why I'm telling you about the depletion region? Why is it necessary?
• The depletion region limits the diffusion of electrons and holes from the opposite doped semiconductor portion, otherwise, after the constant diffusion, all the electrons and holes would have been diffused into each other leaving behind almost no charge carriers to conduct the current when the diode is connected to the battery.
• On the other hand, the size of the depletion region maintains the current flow and resistance. Larger the depletion region, the Larger the resistance. You will understand this concept more easily once we would be done discussing the forward and reverse biasing of the diode and characteristics of the diode. Stay tuned!

Biasing conditions of the Diode

To understand the working of a simple diode, you must know about the biasing conditions of the diode first,

• Forward biasing

• Reverse biasing

• Zero biasing

1. Forward Biasing

• When the positive terminal of the battery is connected to the p-type semiconductor meanwhile the n-type semiconductor is connected to the negative terminal of the battery it is called forward biasing of the diode.
• The depletion region is very thin in this case and it is easier for the forward Voltage or VF to overcome the depletion region for conduction of current.
• PN junction offers very little resistance to the current flow due to the thin depletion region.
• In forward biasing condition, an ideal diode has zero resistance, but as I told you earlier, an ideal condition does not exist.

 2. Reverse Biasing

• In reverse biasing condition, negative terminal is connected to the p-type region of the diode, meanwhile positive terminal is connected to the n-type region of the diode.
• The depletion region in this case is very thick.
• 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.

3. Zero biasing

• Voltage has not been applied to the diode, in zero biasing condition.
• In zero biasing conditions, there is a thermal equilibrium in the diode.
• The natural potential barrier is present in the diode, which is 0.5V to 0.7V for silicon and for germanium this potential barrier is 0.3V.

Characteristics of diode

• We have already learned about the forward and reversed biased condition of the diode, in order to understand the current and Voltage characteristics of both the conditions , consider the following graph consisting of a single characteristic curve.
• The voltage is usually plotted on the x-axis of the graph meanwhile the current takes the y- axis.
• The starting point of the graph can be seen in the center, where both the values i.e current and the voltage is zero.
• Forward current can be observed extending upwards, above the horizontal axis meanwhile, reverse current extends downwards.
• In the upper right corner you can see the combined values of forward voltage and forward current.
• The lower left corner shows the combined value of reverse current and reverse voltage.

Forward Characteristic of Diode

• We have already studied about the forward biasing of the diode, forward characteristic corresponds to that.
• In forward characteristic the current IF flows in forward direction and depends on the amount of forward voltage VF.
• The relationship between VF and IF is called IV characteristic of diode or ampere volt relationship, this is the point of focus of our discussion!
• When forward voltage is zero i.e
• 0V, the forward current IF is also zero i.e 0mA.
• From the graph we can clearly see that the increase in forward voltage , VF causes can increase in forward Current IF, when the value starts from the point 0 of the given graph.
• Now its the turn for the most important point of the curve, the knee voltage denoted as VK.
• You must be thinking why we call it knee voltage? And how is it achieved? Have a look at the line formed , it seems like an extended knee, so we call it knee voltage. Knee voltage is the point where forward voltage VF is large enough to overcome the depletion region of the diode and there is surge in forward current IF, marking the highest point of voltage, knee Voltage VK.
• Knee voltage varies from material to material i.e VK is material specific.

Reverse Characteristic of Diode

• During the reverse biased condition, a very little current is conducted by the diode.
• You can observe the Reverse Voltage and Reverse current in the graph, represented by VR and IR respectively.
• There is a very little amount of charge carriers which conduct the reverse current IR.

• We cannot observe a considerable increase in Reverse current IR even with a large amount of Reverse Voltage VR.
• VBR is one of the most important characteristics of the reverse biased diode, its the breakdown voltage of the reverse biased diode which refers to the amount of voltage at which the reverse current IR increases rapidly breaking the PN junction.

Diode Equation

Following equation refers to the ideal condition of the current and voltage of a diode either in forward biased or reversed biased condition; The equation corresponds to the following things;

• I is the diode current sometimes represented as ID as well.
• IS is the reverse bias saturation current and is not constant for any device, it usually varies with temperature.
• VD is the voltage across the diode
• VT is the thermal voltage which is equal to 25.8563 mV at 300 K.
• In other conditions, Vt equals Boltzmann's constant × temperature ÷ electron charge i.e kT/q
• n is the ideality factor, also called the quality factor and emission coefficient.
• The equation is called Shockley ideal diode equation in which the ideality factor is preset to 1.
• In other conditions, the ideality factor can range from 1 to 2 or maybe higher than that in some cases.
• In forward bias condition, the ideality factor is almost negligible and the equation can be written as;

Types of Diode

With the advancement in technology and increasing human needs, diodes also changed shapes and took over several functions, there are several types of the diode, some of them are explained below;

1. Zener Diode

• It is a heavily doped PN junction diode that works in a reverse-biased condition when a certain specified voltage is reached, this voltage is called Zener Voltage.
• The Breakdown voltage marks the best possible functional capacity of the diode.
• Zener diode is used for voltage regulation, you may observe one in clipping operations, circuit protectors, surge suppressors, and switching applications among the countless other uses which can not be listed here at once.
• They are available in different zener voltages and can be used according to the need.

2. PIN diode

• A PIN diode is a semiconductor diode having a wide undoped semiconductor region sandwiched between heavily doped n-type and p-type regions.
• PIN photodiode doesn't rectify or distort the signal.
• They have a wide range of applications being used in microwave switches and radars.
• PIN diodes are also used in fiber optics and photodetectors.
• Gamma rays and x-ray photons can be detected using a PIN photodiode.

3. Schottky diode

• This is not like a typical PN junction diode, Schottky diode is made by the combination of the metal with the n-type semiconductor.
• Because of the absence of a typical P and N-type combination, we do not see a depletion region in this diode.
• They are also called the hot carrier or Schottky barrier diode.
• These are highly efficient and used in digital devices which are highly sophisticated and fast.

4. Photodiode

• This is one of the most famous types of diodes which are almost known by everyone. A photodiode is a semiconductor p n junction.
• It works in a reverse-biased condition when current is generated on the absorption of light, i.e it converts light in current.
• They have countless applications in the medical, automotive, and other industrial fields such as CAT scanners, PET scanners, light meters, cameras, bar code scanners, and whatnot!
• Photodiodes are used in signal demodulation, detection, and switching.

5. Laser Diode

• Have you ever thought of the full form of the word LASER? You might have, but for the people who haven't, here it is, light amplification by stimulated emission of radiation.
• Laser diode works on the principle of stimulated emission.
• A laser diode works exactly opposite to the photodiode, it converts the voltage into high-intensity coherent light.
• The p-n junction of acts as the active region or laser medium of the diode.
• Laser diodes are highly efficient and can be produced at much lower costs than other diodes known to us.
• Laser diode requires a lower power to operate and produce coherent light than other diodes.
• There are countless applications of laser diodes being used in radiological scans, barcode readers, laser pointers, laser printing, and much more.

6. Tunnel Diode

• A tunnel diode is also known as Esaki diode.
• Tunnel diode as the name suggests works on the principle of tunneling, based on quantum mechanical effects.
• These diodes have a 10nm pn junction which is heavily doped which works on the negative conductance property of the semiconductors.
• Tunnel diodes are used in high-frequency oscillators and receivers, microwave circuits are also made using them.
• They are not widely used in every other circuit because of their low current.

7. Varactor diode

• Varactor diode is made up of two things, a diode and a variable capacitor. They are used as voltage-controlled capacitors.
• It is also named as varicap diode.
• A varactor works in a reverse-biased condition, I hope you know how the reverse-biased condition works, don't fret, if you still don't know, give it another read from the previous sections.
• They are used in frequency modulation, RF phase shifter, and have multiple other applications.

8. Vacuum Diode

• It is the simplest form of the diode and works on the principle of thermionic emission. It does not a PN junction, which are present in the modern day diodes, it's an old school one!
• The cathode and anode are made up of specified metals, different metals are used for the purpose.
• Both the cathode and anode are enclosed in a vacuum tube.
• The cathode is heated with the help of a power supply which in turn releases the electrons, these electrons are then attracted towards the anode.
• The stream of electrons flows from cathode to anode generating current.
• Vacuum diode only works in forward biased condition, in reverse biased condition, it does not work.
• It is the most primitive form of the diode and was used in almost every electronic appliance in the twentieth century, when technology was about to touch the new horizons, there were many available options such as radio, television, computers, and telephones to name a few with a vacuum diode as their functional component.

9. LED

• First things first, please do not call it LED diode, led already is a complete word, Light emitting diode, you can not write it , light emitting diode diode, or can you?
• Who is not aware of the light emitting diodes in this modern age? With endless advertisements and media campaigns, we all have a vague notion about LEDs to an extent.
• Light emitting diodes are similar to laser diodes but they do not emit laser beams on applying voltage.
• LEDs work in forward biased conditions i.e on applying and increasing voltage, current also increases emitting a non-coherent light.
• They are widely used in digital devices for display screens, optical fiber communication, and several detection systems.

10. Gunn diode

• If you remember, I told you earlier about the diodes without a PN junction, Gunn diode is one of them.
• The Gunn diode is a transferred electron device TED, which works on the Gunn effect, named after a scientist. It's a negative differential resistance device.
• There are three regions in total, N- region is the negative region, which is sandwiched between two P+ regions which are heavily doped.
• The materials used in the formation are Indium phosphide and Gallium Arsenide.
• It is a low-power oscillator used in the production of microwaves.
• Gunn diode provides high reliability, and high bandwidth at comparatively lower costs than other available options.

Applications and examples of Diode

As we are at the terminal stage of our discussion, you must be aware of the wide window of utilities we have for diodes, here is the list of few uses of diode which you might already know to an extent;

1. Inverter Technology

• You must be aware of the inverter technology used in modern appliances, they make use of rectifiers which convert the alternating current into direct current.
• Power conversion with the help of diodes has worked as the game-changer in the electronic world, the conversion of alternating current into direct current or higher dc voltage has revolutionized modern technology. You might have seen endless advertisements of invertors technology in home appliances such as air conditioners, and refrigerators to name a few.
• Automotive alternators and voltage multipliers are the well-known examples in this respect.

2. Boolean logic gates

• All of us have thoroughly learned boolean algebra and its logic gates in physics or somehow in computer sciences as well, I always had a love-hate relationship with the logic gates, I still don't know why!
• Those logic gates especially the AND and OR logic gates can be made using diodes and other necessary components required to complete the circuit.
• Diode logic gates were used a lot in the earlier production of computers when other available options were not cost-effective.

3. Signal Demodulation

• Do you know, what is signal demodulation? Let me answer this first, Picking up the actual signal from the modulated wave is called signal demodulation.
• Signal demodulation is carried out by the diode, usually for radio signals.
• The basic task is to remove the negative signals from the carrier wave, generating a clear output signal in terms of sound or an image.
• Signal demodulation is one of the most important things done by diodes.
• Can you guess how this process is carried out? The AM envelope detector, which is simply a diode and an RC circuit the leads for demodulation.

4. Electronics

• From transistors and rectifiers to Light emitting diodes and an endless spectrum of usage, diodes have a significant place in electronics.
• Diodes have plenty of variants to choose from, such as Diode 1n4004 is the most famous diode, which is used for rectification. It has a maximum current carrying capacity of 1A, there are plenty of options you can use as per your requirement.
• One of the most observed examples includes the LEDs, the festive fairy lights to large traffic signal lights and radiological detectors, we all have seen endless diodes in our lives.
• Zener diodes and tuning diodes act as voltage regulators, without them, your circuits would suffer a burnout soon, nobody can withstand a financial and human loss in general at such a large scale.
• We have discussed all of them in detail, you can refer to the section above, in case you have skipped it!

5. Bypass Diodes in Solar panels

• Hot spot heating is one of the many problems faced by the solar system, the solar cell gets damaged due to the low output in presence of shade, dust or snow or any other factors hindering the sunlight to the solar cell.
• Now, you must be thinking about how a hotspot is formed even though the cell itself is not working?
• It is absolutely true that the cell is not working, but the other cells are functional and the current of these cells flow through this faulty cell, heating it up and making a hot spot.
• For this purpose, to protect the faulty cell, bypass diodes are used. This is one of the least celebrated uses of diode indeed!
• These bypass diodes are connected in parallel with the solar cells which helps to reduce the flow of current through the flawed solar cell, making the current flow through an external circuit.

6. Diodes as Clippers

• Let's first discuss the function of a clipper circuit, in case you don't know, a clipper circuit is used to cut down certain parts of the signal, without disturbing the actual waveform, imagine you are making a sandwich with the sandwich cutter, upon cutting with the stencil the sandwich takes the shape of the cutter only from the corners, shedding off the extra parts and bits, but the actual build and assembly of the sandwich is not disturbed, the clipper does the same with the signals.
• These clippers are usually of two types, shunt clippers and series clipper, depending on their function.

7. Diodes in Radiology

• Have you ever been to the hospital for a scan? For a broken bone or for a diagnostic one?
• Laser diodes are the ones used for this purpose, we have already read about them in detail in our previous section.
• Nowadays, laser diodes are even used for surgical treatments such as retinal repair, and other eye-related surgeries. Lithotripsy is also done by laser, the stone in your kidney is broken from outside of the body, through a laser beam without any incision. Isn't it revolutionary? Definitely, it is!

So, friends, it was all about diodes, I presume you have a clear understanding of many concepts related to diodes including their basic structure, working,  types, and applications. I tried to keep it simple but significant, You can re-read the section you least understood, it happens to everyone and it helps. See you with another soon, have a good day ahead!

Workforce Management Principles: Guides on Applying The Best Practices

There is no other area in the construction industry that needs a change more than resource management. Resource management is how you manage, plan, and allocate your workforce. Effective construction workforce management can help you understand aspects like:

• Which construction project needs more hands?
• Identify over and under-allocated staff.
• Track experience and skills with project history.

Simply put, effective workforce management helps contractors coordinate work and people, ensuring that everyone has the details or information required to do their jobs. However, in order to maintain a productive workforce, contractors have to put in plenty of time and hard work.

Visit https://gobridgit.com/construction-field-workforce-management/ to learn more about the importance of workforce management in construction.

There is no doubt that employees are the business’s most valuable asset. However, they are the most expensive as well. This is the reason why maximizing workforce efficiency and productivity should be your top priority.  When efficiency and productivity peak, the workforce quickly pays for itself.

To achieve this, there are certain workforce management principles and best practices that you need to apply.

Keep on reading as we list some important workforce management principles to know if you are a contractor.

#1 Standardize Key Processes

First things first, you need to create transparency and consistency by standardizing key processes in your construction work like swapping shifts, distributing leave, calculating pay, tracking hours, and so on. Contractors who are able to define these processes make an even playing field for the entire workforce, which creates a mutually beneficial culture of understanding and fairness. This is what the construction industry demands the most. For example, if a worker is not able to take up a shift that you have assigned due to personal reasons, he/she may apply for leave. However, if the process is unclear, things can be left until the last minute, stressing out the worker and leaving you in the lurch. Having an established leave request process in place can easily avoid this situation.

#2 Flexible Communication 

If communication lines are inflexible, even the most robust construction workforce management strategy can fail without a doubt. The role of communication is not widely understood in the construction industry yet. But those who have streamlined conversations between workers and contractors by empowering them with platforms that support continuous communication and connectivity have experienced good results. For example, if one of your workers who is working for a week at a construction site is now needed on a different site can get easily confused about the work and roles. With flexible communication, things can be easily conveyed. This is not just about making phone calls. Not everything needs phone calls. Things can be easily communicated via SMS and email as well. Contractors need to enforce this aspect in their workforce management system in order to streamline the communication process among the staff, workers, and subcontractors.

#3 Automate Number Crunching 

From HR to administration and operations, manually managing the workers’ pay rates and shift times can give you a serious headache. By automating pay, time, and leave calculations, contractors can improve data accuracy and free up time for administrative and HR personnel, allowing them to focus on more complex tasks. It is already understood that workers are paid on an hourly basis in the construction industry. Therefore, managing payrolls can be really daunting because even small errors can distress the workforce, and they may have to wait to get paid until you resolve the issue. Automating these processes can minimize payroll errors, which can result in higher worker satisfaction. Most importantly, you will experience reduced labor costs in the form of improved and robust time-tracking.

#4 Streamline Attendance, Time, and Payroll 

From the perspective of your workforce performance, streamlining attendance, time, and payroll is a proven way to heighten engagement and boost satisfaction. Contractors with automated time and attendance solutions can make things highly engaged for their workers and staff. This is because there will be less stress about tracking employee attendance. And employees know that they are responsible for their own attendance. With biometric systems, keeping track of employee attendance, time, and payroll is a piece of cake. The best part is that these can be integrated with most of the workforce management systems available out there. So, as a contractor, things can get smooth for you.

#5 Integrate and Unlock Insight 

You need to understand that the data collected from your construction workforce management system is worth so much more than holiday leave racked up, pay earned, and hours clocked. Contractors can integrate workforce management processes with core administrative and HR functions that can help them unlock a goldmine of workforce data regarding worker absence, performance, labor, and time. “Datafying”  or “datafication” of the entire process can not only streamline things in the payroll department but can also prove beneficial in optimizing performance, refining budgets, and developing strategic schedules. This way, you can focus more on your construction business and less on internal matters.

#6 Invest in a Quality Integrated Construction Workforce Management System 

Today, there are workforce management systems available in the market that are specifically designed for the construction industry. These systems can help you in optimizing your construction workforce planning. From creating operational efficiencies to mitigating risks and improving your bottom line, all can be achieved using easy-to-use resource planner software. The best part about using such systems is that you can enhance your construction workforce planning with complete employee oversight. That is, from future and current projects to overlapping workload issues, all can be tamed without any hassle. Most importantly, with a quality integrated workforce management system like Bridgit Solutions, you can identify over and under-allocated staff and solve problems before they even have an impact.

Conclusion 

These are some of the best practices that contractors should follow in order to streamline their workforce management. Things take time to get in place, and if you are just starting out, implementing these principles will enable you to focus more on your projects.

Ethereum Transactions

Hello friends, Hope you are doing good and having fun. I am here with another article on the blockchain. Previously, we have discussed the blockchain, some of its concepts, and its characteristics, and today I will talk about transactions. We would also explore the concept of gas in this tutorial. So let’s start by defining a transaction.

What is Ethereum Transaction?

• A transaction is a message signed by an account owner that is added to a block and recorded in the blockchain.
• A transaction is initiated by an externally owned account and then it gets transmitted to the Ethereum network.
• It can be originated only by an externally owned account (an account owned by a human) and not by a contract account.
• Through transactions, one can interact with the Ethereum world. As a result, they change and update the state of Ethereum.

• The transaction can be any action such as transferring ether or calling functions of a smart contract. Consequently, the state of the Ethereum virtual machine (EVM) is changed. For example, when account x transfers some ether to account y, a transaction is initiated and after that, the balances of both accounts are updated. The new balances are then stored in the Ethereum network.
• Any account or node has the right to initiate a transaction. But it must be verified through mining.
• Every transaction has a gas limit and a gas fee. This fee is given to miners as a reward for verifying (or mining) that transaction. I will cover the concept of mining in my next tutorials.

These points highlight the importance of a transaction. You can see that a transaction is the only thing that can change the state of the Ethereum virtual machine. By transaction, you can execute a smart contract or deploy a new smart contract to Ethereum and there is no other way to do that. Contracts cannot deploy themselves, contracts cannot call other contracts unless a transaction is initiated by an externally owned account. So, the Ethereum network state depends on the transactions.

Now, this was the definition and importance of a transaction in the blockchain. In the next part, I am going to explain the structure of a transaction.

Structure of Ethereum Transaction

Any transaction in the Ethereum network has some specific components when it is transmitted to the network. Every node receives the transaction and stores it in its memory. The data of a transaction or the components are listed below:

1. Recipient:

• The address of the account that will receive the transaction is called the recipient. The recipient can be an externally owned account or a contract account. Each transaction is directed towards a recipient.

2. Nonce:

• A nonce is a number showing the sequence of a transaction, Nonce is assigned by the account initiating the transaction.

3. Gas Price:

• Any transaction requires some fee that is paid by the creator of the transaction. The fee is calculated per gas unit. The unit is Wei a smaller unit of ether.

4. Gas Limit:

• The creator of the transaction gives the number of gas units that can be used for the transaction. This is the maximum limit of gas that would be consumed.

5. Value:

• The value specifies the amount of Wei or Ether that the sender account wants to send to the recipient.

6. Data:

• If a transaction recipient is a smart contract then the data contains information for executing functions of the contract. This includes data of variable length.

7. Signature:

• A Signature is the identification of the sender. The signature is generated when an externally owned account confirms and signs the transaction via its private key.

These are the components included in a transaction. In the next section, I will discuss the types of transactions in the Ethereum blockchain.

Types of Ethereum Transaction

The transactions can be classified into three general types that are listed below and defined further.

1. Funds Transfer
2. Contract Deployment
3. Function Execution

Funds Transfer

This type of transaction takes place whenever an account sends some funds (in form of ether) to another account. This transaction has a value associated with it but does not have any data. For example, when account A sends some money to account B for buying something. The gas price is set by the sender.

Contract Deployment

Whenever a contract is deployed on the Ethereum network, this transaction takes place. It has data that is the bytecode of the smart contract. There is no recipient for this kind of transaction. The gas limit must be enough for deploying a contract.

Function Execution

After a contract is deployed on Ethereum, its functions can be called. When a function is called by an account, then this type of transaction occurs. The transaction is directed towards a contract account, therefore the recipient is a contract address. The data contains the function name and its arguments.

So, friends, this was a general classification of transactions. Up till now, you must have got an idea of a transaction and its components. The steps of a transaction generation till its confirmation can be listed as below:

1. A transaction is initiated by the sender. The sender’s account provides important information such as recipient address, data, value, and gas limit. After generation, a hash is created that is called a transaction hash.
2. The transaction has is a unique identifier for a transaction. An example of this hash is given below:

0x2446f1fd773fbb9f080f674b60c6a033c7ed7427b8b9413cf28a2a4a6da9b56c

3. The transaction generated is transmitted to the network and added to the transactions pool waiting to be confirmed.
4. A miner picks transactions for the pool to add to the block. This verifies the transactions. When there are a lot of transactions, the waiting time is more. Therefore, a transaction with a higher gas price would be picked first by a miner. In this way, the miner will get more money.
5. A number called block confirmation number is given to a verified and added transaction. This shows the number of blocks created after the block in which the transaction was added. As the chain length of the blockchain increases, the transaction becomes more and more trusted and immutable.

This is the process through which a transaction passes. I hope you have an idea of it's working. Next time I will be here with another topic. Till then, take care!

What is Solidity Programming

Hello friends, hope you are doing fine and doing great. In the previous tutorial for introducing Smart Contracts, I told you about Solidity. Solidity is a high-level programming language for writing smart contracts. It is the most popular programming language for Ethereum. So, in this article, I will explain the basic components of solidity. Let’s get started by revising the key points of solidity.

Solidity Programming

• Solidity programming language is made for writing code for the Ethereum platform. These codes (smart contracts) help in executing different functions in Ethereum virtual machine (EVM).
• It is easy to learn the language. If you are familiar with C and JavaScript, you can easily learn solidity.
• The code written in solidity is converted into bytecode by solidity compiler. The compiler of solidity language is solc.
• The extension of a solidity file is .solc.
• It is a case-sensitive language.
• Solidity is a statically typed language.
• The process of writing and compilation is shown in the figure below.

The layout of a Solidity File

In this section, I am going to discuss the general layout of a solidity file. It contains different components. The layout of a solidity file is explained below. It has:

1. Pragma
2. Comments
3. Import
4. Contract / Library

Pragma in Solidity Programming

• Before writing the solidity program, you want to mention the version of solidity compiler. So that anyone using the file can choose the correct version for compilation.
• For this purpose, pragma directive is used. It specifies the compiler version of the file.
• Solidity is still growing and a lot of improvements have been made since its development. Therefore, the version keeps on improving.
• The current solidity version is 0.7.4.
• The version is mentioned by using the following syntax.

pragma Solidity ^0.7.0;

I should mention here that semi-colon is the statement terminator in solidity.

• It is declared as the first statement of the program.
• The version number comprises a major build number and a minor build number. When you use ^ character with version number, it means the latest version of the major build number.
• For example, as I declared the version 0.7.0 with ^ character. Here major build number is 7. So solidity compiler of version 7 will compile it.

Comments in Solidity Programming

• Guys, if you are familiar with programming, you must know that programming languages support the option of commenting. Solidity also provides this facility.
• There are two types of comment in solidity:
  • Single-Line Comments: single-line comment means a comment comprising of one line only.
  • Multi-Line Comments: multiline comments consist of more than one line.
• Forward slashes are used for denoting comments. Single line comment is denoted by double forward slash //. While multiline comment starts with /* and ends with */.
• It is a good practice to add comments to your program. This improves readability.

Import in Solidity Programming

• The import keyword helps in importing other solidity files. These files can then be used in code.
• The functions of the imported file can then be used in a solidity file.
• This functionality helps us in writing code in the form of modules. In this way, lengthy code can be converted into smaller readable ones.
• The syntax for using the import keyword is given below:

import filename;

• The address of the file is mentioned within the import statement.

Contract / Library in Solidity Programming

• The contracts are defined in the solidity file.
• You can define more than one contract or library in one file.
• Contracts, libraries and interfaces can be defined one after the other in a file.

So, this was the general layout of a solidity file. Now, I will move to the next section in which we are going to discuss the structure of a contract.

Structure of a Contract

Contracts are somehow similar to classes in OOP (Object Oriented Programming) Languages. The contracts are written for ethereum virtual machine. Just like other languages, contract code contains functions and variables. The contracts can also inherit from other solidity contracts. There are two special types of contracts in solidity called library and interface. In this section, I have discussed different constructs in a contract. The contract consists of the following:

1. State Variables
2. Structures
3. Modifier Functions
4. Event Declarations
5. Enumerations
6. Functions

Now let’s define these for further understanding.

State Variables

• Variables store values in storage locations. The value saved in a variable can be change or update while programming execution.
• Once a variable is declared, you can use it anywhere in your program, at multiple locations.
• State variables are stored in Ethereum blockchain permanently. The changes in their value and their current value is secured.
• The data type of state variable is declared while writing the program.
• Other qualifiers, used while declaration, are listed below:
  • Internal
  • Private
  • Public
  • Constant
• The following data types can be used in solidity:
  • Bool for boolean
  • Uint / int for unsigned / signed integer
  • Bytes for 8 bit signed integer
  • Address for addresses of accounts
  • Mapping for mappings
  • Enum for enumerations
  • Struct for structures
  • String for character strings

Structure

• With the help of structure, you can define a data type of your own.
• A structure is a composite data type and that means it can contain different variables having different or same data types.
• A group of variables is defined in a structure. Each one is given a name and a data type.
• A structure is declared by using the struct keyword.

Modifier

• A modifier is a function that can change the behavior of the code.
• In solidity, modifiers are used with functions, so they can change the actions of a function.
• If you are calling a solidity function that has a modifier associated with it, then the modifier function will execute first. After its execution, the called function would be executed.
• You will define modifier function only once in the program but you can use it anywhere with multiple functions.

Events

• If you are familiar with programming, you know that different programming languages support events.
• Solidity also supports events. Events tell about the change in the state of a contract.
• With the help of logs, the caller can view the state of the contract after execution.
• Events are declared outside functions, at the global level. Then these events can be called in any function.
• The keyword for event declaration is an event. After that, the identifier is declared followed by a parameter list. The parameter list contains the data type of the variables.

Enumeration

• Enumeration provides us with an interesting facility. With the help of it, you can define a data type of your own choice.
• It contains a list of constants, from which the variable can take values.
• Each value is given an integer starting from 0 for solidity.
• The enumeration is declared by the enum keyword. After the keyword, the identifier is defined followed by the list of constant values in brackets.
• There is no semi-colon at the end of the enum declaration statement.

Function

• Just like any other programming language, a function is a key component of solidity.
• Whenever a transaction is initiated, a function of a smart contract is called.
• Functions can read and write state variables. When a function is executed and a transaction is processed, the state variable may change its state.
• A function can take input parameters, perform operations on them and can return values. The return values can be more than one.
• A function has a name that is its identifier. This identifier can be used anywhere in the program for the execution of functions.
• You can use various qualifiers with a function declaration that decides the visibility of a function. These qualifiers are listed below:
  • Public
  • Private
  • Internal
  • External
• Other than visibility qualifiers, some other qualifiers are also used with functions. These show the ability of the underlying function in terms of changing values of state variables. The qualifiers are given below:
  • Constant
  • View
  • Pure
  • Payable

So, friends, I have tried to give you a basic idea of the structure of a solidity program. It is not compulsory for a program to have all of the above-listed features. I hope you have learned and got a good understanding of the basics of this language. That was all from my side. Please let me know if you have any questions. I would love to answer them. I am signing off for today, Take care!

Structure of a Block in Blockchain

Hello guys, hope you are doing good and enjoying your lives. Today, I am going to introduce you to the blocks of a blockchain. I gave you an understanding of blockchain, its characteristics, and some idea about accounts and wallets in my previous tutorials, and today my article is about the structure of a block in the blockchain. I will first define the block before going into the details about its structure. So let’s start without any further delay.

Block in Blockchain

• A block is actually the building block or the key element of a blockchain.
• The definition of a blockchain is based on its blocks. As I defined in my previous posts, a blockchain is a chain of multiple blocks.
• Blocks contain transactions. Each block contains a different number of transactions.
• These transactions are contained in blocks so that they would be added to the distributed ledger.
• The number of transactions is limited by the block size and gas limit. Generally, the block contains more than 500 transactions.
• Other than transactions, a block also consists of some metadata. This metadata is stored in the header of the blockchain.
• The size of a block header is 80 bytes, the detail of which is given in the upcoming sections of this article.
• Let’s first define a parent block in the next part.

Parent Block in Blockchain

As the blocks are linked together one after the other, they have a parent-child relationship. Each block is the parent of the upcoming block. Each child block contains the hash of the previous block i.e., its parent block. The first block of the blockchain is called Genesis Block and it has no parent. The block contains different fields which can be roughly categorized as listed below:

• The block size: The size of this field is 4 bytes and it contains the size of the block.
• The block header: The size of a block header is 80 bytes. It further contains different fields.
• The transaction counter: This field contains the number of transactions and the size of it is between 1-9 bytes.
• The transactions: This field contains transactions of the block and its size is variable.

This was some information regarding the fields of an Ethereum block. Now, we will move towards the next part in which I am going to give you an idea about the block header and its fields.

Block Header in Blockchain

The header of an Ethereum block contains different fields of metadata which are listed below.

• Hash of the previous block: Every block header gives information about the previous or parent block. This field contains the hash value of the previous block and this reference connects all the blocks. The size of this field is 32 bytes.
• Version: This field stores the version number to show software upgrades. The size of the version field is 4 bytes.
• Difficulty: The mining difficulty at the time of the block creation is stored in this field. The concept of mining would be explained in the upcoming articles. Its size is 4 bytes.
• Timestamp: This field contains the time at which the block was created. The size of this field is 4 bytes.
• Nonce: A nonce is a value used during the mining of the block. This field’s size is also 4 bytes.
• Merkle tree root: A Merkle tree is a structure obtained from hashing the transactional data of a block. The root of this tree is stored in the block header under this field. 32 bytes is the size of the Merkle tree root field.

This was all about the header of a block. In the next part, I am going to give you an idea about the properties of a block.

Properties of a Block:

There are a lot of properties of a block that give us important information about it. I am listing down the properties here.

Difficulty Property:

• As I mentioned earlier, this property gives the difficulty level of solving the puzzle to mine the block.

totalDifficulty Property:

• This property of the block tells us the total difficulty of the blockchain.

gasLimit Property:

• This property tells us the maximum gas allowed by the block which in turn tells us about the number of transactions that the block can accommodate.

gasUsed Property:

• The gasUsed property gives the amount of gas used by the block for executing all of its transactions.

Number Property:

The number shows the block number in the list of blocks.

Transactions Property:

• This means all of the transactions contained in the block.

Hash Property:

• This property shows the hash of the block.

parentHash Property:

• This property saves the hash of the previous block.

Nonce Property:

• Nonce property shows the nonce value that I defined earlier. It is a variable used in mining the block.

Miner Property:

• The miner property gives information about the miner of the block. This gives the account of the block miner.

So guys these were the properties of a block. I will move towards the next part i.e., the identification of a block.

Block Identification:

The blocks of a blockchain need an identification to refer them or distinguish them from other blocks. Two parameters are used for this purpose which are given below:

1. Block Hash

Block hash is the main identification parameter of a block. This value is obtained by cryptographic hashing of the header of the block. The hashing operation is performed twice. The header of the block contains metadata of the block and when this data is hashed the result is the block hash, whose size is 32 bytes. The hash of the block is not stored in the block’s data whether the block is being transmitted to the other nodes or it is stored as part of the blockchain on some node. When a node receives a block from the network, it computes its hash itself.

2. Block Height

The second parameter used for identifying a block is its height. As we already know that the blocks are linked together in a list type structure starting from the genesis block. The genesis block is given a height 0 zero. The second block in the blockchain or the first block after the genesis block is at height 1 and so on. In this article, I have explained the structure of an Ethereum block. The article explained the header and some properties of the blocks. I hope you have learned something new from it. Take care!

Real Time Embedded Systems: Definition, Types, Examples and Applications

Hello friends, I hope you are happy, healthy and content. We have been discussing embedded systems lately and this discussion would be incomplete without an in-depth discussion on Real time embedded systems. You might have observed their utility and their absolute need in our constantly changing external and internal environment, the ease of managing the room temperature with a single tap, generating several results with a single click and streaming videos and playing games anytime and anywhere are the blessings of real time embedded systems.

Definition of Real Time Embedded Systems

Real time embedded systems can be defined as;

• "The embedded systems which respond to real time situation with the help of its embedded software and hardware, within the specified time constraints are called real time embedded systems."

Characteristics of a Real-Time Embedded System

Real time embedded systems must have the following characteristics;

1. Constant Response:

• A real-time embedded system always responds in the same manner to a certain situation, it is not allowed to deviate from its normal designated output. An air-conditioner is not allowed to throw hot air in summers.

2. Deadline:

• A deadline is crucial to the working of an embedded system, a missed deadline can cost lives and finances.

3. Accuracy:

• In case of any malfunctioning, the system failure can cause havoc, what would happen if the pacemaker can't maintain the heartbeat, patient would eventually die!

4. Quick Response:

• It is the most important characteristic of all, the real-time embedded system must be swift enough to respond to the changing external environment with immediate effect.

Components of Real Time Embedded Systems

We have already discussed the embedded system components in detail within our previous article, for a quick overview , let's revise the basic things;

1. Hardware

• The hardware parts include a microcontroller or a microprocessor, Input and Output ports, sensors , actuators , relays, power supply or batteries and several other peripheral parts according to the design and function of the embedded system.

2. Software

• Real time embedded systems have embedded software which directs the system for performing designated tasks.
• For a real time embedded system, embedded operating systems software must have the critical feature of task scheduling, because we need a system which sticks to the deadline and performs the task within that limited time range. Let's have a look, how task scheduling is done;

Task Scheduling

To understand task scheduling you must understand pre-emptive and non-preemptive scheduling.

Preemptive scheduling

IT refers to the scheduling of tasks based on priority, it is a flexible process and interruption between the tasks doesn't upset the whole system. It's same as you are washing dishes and someone ask for a clean dish at immediate basis, you leave the thing in your hands and start washing that dish which is needed immediately!

Non- preemptive scheduling

it is a rigid process, the other task at hand has to wait until the first one has been completed. Now, you are well aware of the types of approaches used in task scheduling, its time for a detailed outlook on the basic types of Task Scheduling done in the real time embedded systems.

First Come First Served Task Scheduling

• As the name clearly indicates, the task that is assigned first is completed first.
• This is a non-preemptive scheduling approach.
• The system is highly efficient and tries to complete the task real quick and responds quickly.

Round Robin Task Scheduling

• In this task scheduling technique the preemptive approach is applied, but there is a difference, it doesn't priorities a task, instead it allocates the time for each task.
• Its same as, you have an exam tomorrow morning and you allocate 2 hours to each chapter for revision!

Shortest Job First Task Scheduling

• All of us have done this at some point of our lives, if you aren't a very diligent student, you choose the shortest paragraph to read first. Isn't it?
• Same is done by the preemptive scheduling system in this case, the task which can be performed quickly , is chosen and performed first.
• If a new task is assigned which can be performed earlier than the one being performed at hand, the system starts performing the shorter one which has just arrived, unfair! Isn't it?

Priority Scheduling

• Let's suppose its your best friends birthday and you are in charge of all the celebrations or we can say a surprise birthday party, what would you arrange first? snacks?, decorations? or a birthday cake? The answer is clear , it would be a birthday cake winning the priority list.
• Same is the case with priority scheduling, the system prioritizes all the tasks at hand, but the one with utmost urgency and priority is performed first.
• This system can be designed using both the preemptive and non-preemptive approaches.

Real time operating system

• Real time embedded systems are everywhere around us and have real time operating system as their basic component, they are almost similar to embedded operating systems , only having a few particular features different from the typical embedded operating systems due to the task specifications.
• RTOS are implied in the embedded systems which are time sensitive.
• Time constraints are the key, a task completed after due time or deadline would be rendered useless or would have a negative impact on the users. You can't enter your lecture hall after the starting time of your lecture without feeling guilty of being late!
• Time maintenance component is crucial to the real time operating system, tasks are specified and given preference according to the time constraints of each task.

You can refer to the diagram for the components of a real time embedded system.

Types of Real Time Embedded Systems

As we are done with the definition and components of a real time embedded system, being made up of real time operating system, embedded software and hardware.It would be easier to learn their types. Real Time embedded systems have the following three types, we would discuss each of them in detail.

1. Soft Real Time Embedded Systems

Following are the characteristics of soft real time embedded systems;

• In soft real time embedded systems, timeliness of a task poses a positive impact on the system, but it is not crucial for the performance of the system.
• Missing a deadline would not degrade the performance of the whole embedded system.

Example of Soft Real Time Embedded System

A data acquisition system can tolerate delays and hence its a soft real time embedded system. Other examples include, websites, computer games, cellular networks, online database and multimedia transmission and reception.

2. Hard Real Time Embedded Systems

Following are the characteristics of hard real time embedded systems;

• For a hard real time embedded system, time is crucial.
• The output must be completely on time, the prescribed deadline can not be missed in any case. You can't submit your exam paper after the time is over, or can you?
• In case a deadline is missed, it would be regarded as a system failure.

Following table shows the brief account of characteristic features for both soft and hard real time embedded systems.

Example of Hard Real Time Embedded System

The missile launch system is one of the most suitable examples in such systems, if the missile is not launched in time, it would miss the target claiming a huge environmental, economic and human loss. Other examples include medical equipment and handheld devices, avionics, industrial control systems, and transportation control.

3. Firm Real Time Embedded Systems

Following are the characteristics of firm real time embedded systems;

• Timelines of a task are crucial but the missed deadline can be compensated as it occurs rarely.
• Missed deadline doesn't degrade the system performance.
• In case of the missed deadline, The system continues to perform and discard the delayed response.

Example of Firm Real Time Embedded Systems

A fully automated assembly line doesn't crash when a task isn't performed in time, it rather ignores that missed part and continues to complete the rest.

Examples of Real Time Embedded System

• Real time embedded systems examples are being listed below, we will only discuss the few basic ones in detail out of an endless list.

Cardiac Pacemaker - A Real Time Embedded System

• First one on the list is a pacemaker, let's have a brief idea about the function of pacemakers first, a pacemaker maintains the heart beat, so is crucial to human life. A pacemaker is a real time embedded system.

• The sensors present in the pacemaker detect the intensity of the beat and send an electrical signal, if its too low to maintain normal function of the heart, in response to this signal an electrical impulse is generated to maintain the already diminishing heartbeat, your heart can't skip a beat, otherwise you'd die of heart attack! It only happens in movies.

Airbags- A real Time Embedded System

• Who is not aware of the importance of air bags in this era of modern vehicles! Airbags are indeed one of the most celebrated safety inventions of modern age.
• Air bags are necessary for human survival in case of a road accident which is obviously a life threatening condition.
• The airbags are inflated on the detection of collision or crash by the sensors, upon detection certain chemical react instantly to inflate the bags, providing cushion to the passengers to land on, saving passengers from serious injuries.
• Hence, airbag system of a car is a real time embedded system which works within strict time constraints, otherwise it would be useless for an airbag to inflate after the passenger has already got a whiplash injury during collision, ending up in a hospital bed or a deathbed.

Manufacturing Assembly Line

• The above mentioned examples were the life threatening ones, the one we are about to discuss is light and crispy!
• Now consider a manufacturing assembly line for production of Lays, the one you have seen in your childhood on national geographic, or maybe you were lucky enough to see it in real!
• What would happen if the automated system fails to fill in the chips in designed time? It doesn't happen that much, but just imagine for an instance!
• That one delayed step would disturb all the preceding steps in line, such as sealing and flavouring the packets.
• This is not life threatening situation , but a delay that would cost millions or much more. Packaging is just the terminal step, you can yourself imagine the importance of timelines in the whole manufacturing process.
• Or in another instance the missed step would be ignored if it is not on a large scale and the process would continue, the same thing that happens in firm real time embedded systems. It all about programming the system according to your personal preference and available resources.
• Thus a manufacturing assembly line is a real time embedded system, which needs to be in time.

Crusie Control of a Car

• Cruise control which once seemed a crazy concept a while ago is now a new normal for longer trips.
• It's a real-time embedded system that controls the speed of a car.
• The real-time embedded software algorithm has basic features of keeping the car at a preset speed as indicated by the driver, maintaining a safe measurable distance from a preceding vehicle, and lastly it is designed to switch between the two discussed modes according to the real-time situation on road.
• A minor miscalculation of the speed and distance would cause havoc on the road, thus real time embedded systems need to be accurate and on time during their performance.

Safety critical systems

• We have discussed safety critical systems in one of our previous articles as well, but a discussion on real time embedded system without an example of a safety critical system is incomplete.
• First things first, Safety Critical Systems are real time embedded systems.
• You might have got a slight idea about the safety critical systems from their name, The systems which can't afford delay are called safety critical systems, their output delay can claim a human life, can pose serious financial and environmental crisis.
• One the most common example is a missile launching system.
• Missile launching system is a real time embedded system, imagine the destruction with one single delay or miscalculated response. Another example include shuttle launch in space which is also a safety critical system.

Applications of Real Time Embedded Systems

  Real time embedded system applications are countless, a few popular ones are being discussed below;

Medical Industry

• Real time embedded systems are deeply rooted into the healthcare sector either in the form of handheld devices such as insulin pump, BP apparatus, pulse oximeter or large devices such ECG machines, and industrial scanners, real time embedded systems are everywhere.
• These embedded systems have made diagnosis , treatment and prognosis much easier than before. Diagnosis and treatment would be a difficult thing to do without the real time embedded systems, how would you identify a tumor without a scan? How insulin levels would be checked? Nobody can deny the importance of real time embedded systems in the medical field.

Manufacturing and Assembly Lines

• Real time embedded systems have revolutionized the automation of production lines, you might see the fully automated processes of biscuits, chips and soda in documentaries or maybe in real. Have you ever thought how it is done? The mechanism and machinery behind the fully automated processes? These are large robots with real time embedded systems, performing their designated tasks in a real time environment.
• Control of internal environment according to the manufacturing process, for humidity , air pressure and temperature is also done by real time embedded systems. Would you ever like soggy lays? Or a soda without gas? A cookie without crunch? No! Nobody does! All these factors are controlled by real time embedded systems through predictive maintenance.

Military Operations

• Either it is a preventive or defensive approach, real time embedded systems are an essential part of a bigger picture in military armaments.
• You might have heard of guided missiles, detection systems and much more intelligent weapons, all these systems are real time embedded systems.
• In military SWaP size, weight and power is a decisive factor of winning and losing for the soldiers in the battlefield, real time embedded systems, reduce size and weight of the power gear and provides quicker and better turnover during a strike.
• Microcontroller technology has led to the reduction of production costs along with the manufacturing of lightweight power gear.

Home Automation

• You might have seen the central cooling and heating systems, smart lighting system, security system, fire alarm, security surveillance system and many other systems that are controlled by the sensors by collecting data from external environment, these are real time embedded systems which have added to the ease of human beings.
• All the above mentioned systems are controlled through internet but they can be regulated manually as well.
• We have already discussed in detail the concept of a Smart home, in which several electronic devices are connected to a central hub through internet. Real time embedded systems have helped a lot in turning this unpopular concept into reality. To say the least, it is indeed an expensive concept.

Automotive industry

• Automotive industry has reaped the benefits of the real time embedded systems to full extent.
• Can you imagine a car without a GPS system these days? No , its an absolute necessity now!
• Crusie control, smart parking, car tracking, traction control system, and a lot more which are a part of another bigger picture have real time embedded systems in them.
• Hybrid vehicles which consume less fuel and save environment are a gift of real time embedded systems as well.

Multimedia Systems

• Multimedia systems which provide the audio and video interface to their users, have real time embedded systems as their integral part.
• The gaming world would be incomplete if real time embedded systems are not implied, many of the modern games are also networked and played live among the users from all over the world at the same time.

So, friends, that's all about the Real Time Embedded Systems, I have tried to cover everything regarding this topic. I hope you have learned something new from this article. In case you want to add something new to the list of applications or examples of embedded systems, you can mention in the comment section below. See you soon with another topic. Have a good day ahead!

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