Category: Physics Notes PPT

An Introduction

Before we talk about the phase difference and the path difference of a wave and the relation between these two quantities, we should know what are the different types of waves and the properties of waves.

 

Types of Waves

There are two basic types of waves which are as follows:

1. Mechanical Waves: These are those types of waves that can be described as the oscillations of matter. These types of waves require a medium to transfer energy. Examples of mechanical waves can be sound waves, water waves, waves associated with a rope, etc. 

2. Electromagnetic Waves: These are those types of waves that do not require any medium to travel and transfer the energy possessed by them. This means that they can travel in a vacuum as well and these include x-rays, gamma rays, UV rays, etc.

Properties of Waves 

Wavelength: The distance between two consecutive crests or the distance between two consecutive troughs of a wave is known as its wavelength which is measured in meters as well.

Displacement: Displacement can be described as the total distance of a particle from its mean position which is always measured in meters.

Amplitude: Amplitude is the height of a crest or depth of a trough of a wavelength or it can be described as the maximum displacement of a particle. Amplitude like displacement is also measured in meters. 

Time Period: The time period of a wave is defined as the time taken by that wave to complete one full oscillation. The unit in terms of which the time period of a wave is measured is second. 

Time period = [frac{1}{frequency}]

Frequency: The frequency of a wave can be described as the number of complete oscillations made by that wave in one second and the unit of frequency is Hertz (Hz). 

Frequency =[frac{1}{text{time period}}]

These were some common properties of waves, now we will talk about two additional properties of waves i.e., the phase difference and the path difference. These two properties of waves are discussed below. 

If we talk about the phase difference, it can be called the difference in the phase angle of the two waves while the difference in the path traversed by the two waves can be described as the path difference. The phase difference increases with an increase in the path difference and decreases with a decrease in the path difference which implies that both these quantities are directly proportional to each other. Here, in this article, we will talk about the phase difference, the path difference, and the relation between them.

Phase Difference and Path Difference

If we take two waves that have the same frequency, the relation between their path difference and phase difference is given as: 

[triangle]x = (λ/2π).[triangle][phi]

Where the path difference between the two waves of the same frequency is Δx and the phase difference between the two waves is[triangle][phi]. 

Meter is the unit.

The above equation can be written in other ways as well. For example, the general equation that relates the path difference with the phase difference can be written as:

([triangle]x/λ) = ([triangle][phi]/2π) 

If we check, we will find that this relation has no units.

From the above equation, we can derive the formula for the path difference which comes out to be:

[triangle][phi] = (2π.Δx)/λ

After solving this equation, we find that the unit of path difference is Radian or degree. 

We can also derive the formula for the path difference from the relation between the path difference and phase difference which comes out to be:

[triangle]x = (λ/2π).[triangle][phi]

After solving the above equation, the unit of the path difference comes out to be ‘meter’. 

So, we have discussed the relation between the phase difference and path difference relation. From that equation, we derived the equation of the path difference ([triangle]x) in terms of the phase difference and found out that its unit is meter. 

Similarly, we derived the equation of phase difference ([triangle][phi]) in terms of the path difference and also found that the unit of the phase difference is radian or degree. 

Let’s now talk about some of the properties of waves. 

There’s an important point to remember here which is that the phase difference can not be defined for a single wave. It is defined when two waves of the same frequency are taken into consideration.

Relation Between Phase Difference & Path Difference 

For any two waves, the relation between the phase difference and the path difference can be stated as:

[triangle]x=λ2π = [triangle][phi]

The above is the phase difference and path difference relation.

Here,

[triangle]x = path difference

[triangle][phi] = phase difference

The path difference and the phase difference have no SI units that means their unit is one.

We define the phase difference between any two consecutive points in terms of radians, whereas the path difference is the integral number of wavelengths in a phase.

Now, let’s discuss the relationship between phase difference and path difference.

Path Difference Definition Physics

The path difference between the two varying waves is the difference in the distance they covered.

The path difference is the difference in the physical distance between the two sources to the observer, i.e., the difference in distance traveled from the source to the observer.

Phase Difference

Articles in waves oscillate. When they oscillate (move to-and-fro), the particles go through phases, from 0° to 360° or zero to 2π.

Where π is one period. The particles go through phases, from When the particle travels the distance of one wavelength (since a particle travels the distance of one wavelength in the time duration of one period).

Consider the displacement-time and displacement-phase graph of particles drawn below:

In one period, the particle undergoes a phase change of 2π.

Now, take any two points in time where the particles’ motion and position are the same. The difference/variation in their phase is their phase difference.

In the example above, the period for both particles is  4s and the phase difference between the particles is π/2.

Similarly, we can draw a parallel between the distance between the source and the phase. 

When particles make a displacement equal to their wavelength, they go through phases from 0 to 2π.

For better visualization, let’s consider Particle A and Particle B starting from s = 0 and s = – 2, respectively.

Over a certain period of time, both particles will go through a complete oscillation and go back to their respective starting positions. The time taken is known as the period T (both their periods are
4s.

Imagine that we are big fans of these two particles. We take 360 photos of them within 4, while they are dancing. With this magical camera, we can capture both the position and the direction of velocity. 

Now, what we have to do is, we have to take 360 photos of the same particle from time to time. Here, each photo represents each particle at different phases.

0°, 0°

1°, 1°

2°, 2°

3°, 3°, and so on.

Suppose that we notice that Particle B in Photo 90 looks exactly like Particle A in Photo 0°, i.e., their position and direction of velocity are the same. This means that Particle B “lags” behind Particle A by 90 photos. This means that they have a phase difference of 90° or π/2.

Phase Difference Waves

We define the phase difference of a sine wave as the time interval by which one wave leads or lags by another one. One must note that the phase difference is not a property of only one wave, it is the relative property to two or more waves.

We call the phase difference the “Phase offset” or the “Phase angle”. We represent the phase difference by the Greek letter Phi symbolized as to[phi].

The phase difference is represented by the following sine wave:

Phase Difference and Path Difference Equation

The equation for the path difference and the phase difference relation is given by:

Phase difference (in radians) = 2π(path difference in m)λ(wavelengths meter )

Difference Between Phase Difference and Path Difference

To know more about the relationship between phase difference and path difference, log on to to find out what the experts have to say.

In physics, you often hear the word torque. Do you know exactly what torque means? Well, a torque is nothing but the force applied on an object to make it rotate about its axis. Therefore, any force that can cause this angular acceleration in an object is torque. 

 

As you can probably understand from this definition, torque is a vector quantity because both the magnitude and direction of a force are at work here. The torque vector direction depends on the direction of the force on the axis. 

 

A common question that can arise when learning about torque is its relation to speed. Therefore, listed below is the equation that pits torque vs speed.

 

[text{Torque}(tau) = frac{Power}{speed}]

 

This is the most basic form of a relation between torque and speed. If you desire to know more, you must first determine what speed is. 

 

Quick Exercise – 1

Q. A wheel moves at a rate of 0.3 m/s on applying a power of 40 Watts. Determine the torque acting on the wheel using a torque-speed relation equation.

Solution –

Speed of the wheel is 0.3 m/s

Power applied on the wheel is 40 watts

Thus, [Torque = frac{Power}{speed}]

[Torque = frac{40}{0.3} ]

Torque is equal to 133.33 Newton-metre. 

 

What is Speed?

To assess torque vs speed truly, you must first understand speed in detail. Speed is nothing but the distance traveled by an object per unit of time. Speed is a scalar quantity. You do not need to establish the direction of movement to determine the speed of a body.

 

This is also what sets speed apart from velocity. Being a vector quantity, velocity is the speed of a body in a particular direction. 

 

Torque and Speed Formula

Both of the relationship between these two and their formula can be easily understood by the formula to calculate the power carried by an object moving in a circular motion.

 

[Power = Torque times Speed]

 

[P = tau times omega ]

 

Where p represents the power or the work done by the object in a circular motion. T is the torque (Torque is considered as the rotational ability of a body, considered like the equivalent of force) and [omega] is the angular speed or velocity attained by the moving object (considered as the rate of change in angular displacement).

 

The equation above can be rearranged to get the formula to find the torque on  the moving object

 

[tau = frac{P}{omega}]

 

Similarly, the formula to calculate the speed (Angular speed/ velocity)

 

[omega= frac{P}{T} ]

 

The force in here is typically measured in Watts (W) or horsepower (hp). In motors, it is basically the mechanical output power of a motor. For electric motors the speed is measured in the revolutions per minute, or RPM, It defiance the rate of rotation of the moving part. Torque for electrical appliances is measured in either inch pounds (in lbs) or Newton metres (N m) and it defines the force exerted on the motor or the other object in circular motion. It is the rotational force that the object deleveloped.

 

Deriving the Relation Between Torque and Speed Formula

Since torque is a rotatory motion, we can easily derive its relation to power by comparing the linear equivalent. To determine the linear displacement, simply multiply the radius of movement with the angle covered. Keep in mind that linear displacement refers to the distance covered at the circumference of a wheel.

 

Therefore, we can say that [text{Linear distance} = Time times text{Angular velocity} times Radius] (eq.1) 

 

We know that [Torque = Force times Radius ]

 

[Force = frac{Torque}{Radius}] (eq.2)

 

Now, [Power = frac{Force times text{Linear Distance}}{Time} ]

 

Integrating the value of force from eq.1 and eq.2, we get

 

[Power = frac{(frac{Torque}{Radius}) times Time times text{Angular Velocity} times Radius}{Time} ]

 

Thus, [Power = Torque times text{Angular Velocity}]

 

Consequently, [Torque = frac{Power}{text{Angular velocity}}]

 

What is the Relationship Between Torque and Speed?

The mathematical formula tells us that this force around an axis is inversely proportional to speed (angular velocity). This means that an increase in velocity causes torque to drop and vice versa.

 

Another vital factor that you need to keep in mind is that in this equation velocity and speed is used interchangeably. This is because torque, being a vector quantity, will always have speed in a particular direction. Now that you know the torque and speed relation, answer this simple question.

 

True or False – 1

Q. Torque is directly proportional to the radius of rotation.

Ans. True. Since torque is the product of force and radius of rotation, increasing this radius will also increase the resulting torque. The same is true for the opposite as well.

 

Relation Between Torque and Speed in DC Motor

In a DC motor, speed is calculated in the form of rotation per minute. Thus for such a motor, you can determine torque, by using the following formula – 

 

[Torque = frac{Power}{(2pi times text{Speed of Rotation})}]

 

Our online classes and a wide selection of PDF books will help you further your understanding of torque vs speed. We also have doubt-clearing sessions to ensure proper comprehension of each topic. Now, you can even download our app to access online sessions with ease.

Electricity always flows from higher potential to lower potential in a circuit. A regular circuit contains conductors, resistors, a switch to turn on and off the circuit, and a power source. All of these different components can be connected in multiple ways to produce a complicated network. Therefore, solving resistors in series and parallel is important. A resistor is an electrical component that provides resistance or limits the flow of current in the circuit. For example, we can consider a tube light used in our household as a resistor. Therefore, solving resistors in series and parallel is essential.

Normally, we have a combination of resistors used in all circuits. We can either have resistors in series or resistors in parallel. In this article, we will look at resistors in series and parallel problems and solutions.  

Series Combination of Resistors

We say that resistors are connected in series when the resistors are connected one after the other. The current flows through them one after the other, and Voltage will keep dropping from one resistor to another.

To calculate the equivalent resistance, we need to derive the series resistance formula. To obtain the equation, we use Ohm’s law. According to the law, the potential drop ‘V’ is given as V=IR, where ‘I’ is the current, and ‘R’ is the resistance of the circuit. 

According to Kirchhoff’s loop law we have,

[sum I_{in} = sum I_{out}]

I = I1 +I2

[I = frac{V_{1}}{R_{1}} + frac{V_{2}}{R_{2}} = frac{V}{R_{1}} + frac{V}{R_{2}}]

[I = V(frac{1}{R_{1}} + frac{1}{R_{2}})]

[R_{p} = (frac{1}{R_{1}} + frac{1}{R_{2}})^{-1}]

Therefore, we get the resistors in the parallel formula as,

[R_{p} = (frac{1}{R_{1}} + frac{1}{R_{2}} + frac{1}{R_{3}}  + . . . + frac{1}{R_{N – 1}} + frac{1}{R_{N}})^{-1}]

[R_{p} = (sum_{i=1}^{N} frac{1}{R_{i}})^{-1}]

Using this formula, we will try to solve questions on resistors in series and parallel. We will now look at some resistors in series and parallel problems and solutions. You will also be able to find some series-parallel resistance practice problems on our page.

Solved Problems

Question 1) Consider a circuit with a voltage of 9V, and consisting of five resistors with a resistance of 30Ω each. Calculate the equivalent resistance, and the current ‘I’ through the resistors.

Answer 1) Looking at the figure, we can see that the resistors are in series. 

Given: V = 9V

R1 = R2 = R3 = R4 = R5 = 30Ω

The equivalent resistance is given as,

RS = R1 + R2 + R3 + R4 + R5 = 30Ω + 30Ω + 30Ω + 30Ω + 30Ω = 150Ω

The total resistance with the correct number of significant digits is Req = 150Ω.

Using Ohm’s law, we can calculate the current in the circuit.

I = V/RS = 9V/150Ω = 0.06A

Therefore, we were able to find the equivalent resistance to be 150Ω and the current as 0.06A.

Question 2) Three resistors R1 = 1.00Ω, R2 = 1.00Ω, and R3 = 1.00Ω, are connected in parallel. The battery has a voltage of 3V. Calculate the equivalent resistance, and current ‘I’ through the circuit.

Answer 2) Since the resistors are connected in parallel, we will use the resistors in the parallel formula to calculate the equivalent resistance.

Given: V = 3V, R1 = 1.00Ω, R2 = 1.00Ω, R3 = 1.00Ω

The equivalent resistance is given as,

[R_{p} = (frac{1}{R_{1}} + frac{1}{R_{2}} + frac{1}{R_{3}})^{-1}]

[R_{p} = (frac{1}{1} + frac{1}{1} + frac{1}{1})^{-1}]

[R_{p} = 0.333 Omega]

Therefore, we get the equivalent resistance as Req = 0.333Ω.

Using Ohm’s law, we can calculate the current in the circuit.

[I = frac{V}{R_{p}} = frac{3V}{0.333Omega } = 9A]

Therefore, we were able to find the equivalent resistance to be 0.333Ω and the current as 9A.

Now that you have gone through resistors in series and parallel problems and solutions. You should easily be able to solve any questions on resistors in series and parallel.

You must have seen the motion of a rolling ball or a wheel many times, but do you know the kind of motions that an object and its particles undergo while in rolling motion? A combination of translational and rotational motions happen during the rolling motion of a rigid object. To define rolling motion, we must understand the forces like angular momentum and torque. This article will give you the definition of rolling motion, and you would also learn rolling motion equations here.

Rolling Objects Physics

When there is a rolling motion without slipping,  the object has both rotational and translational movement while the point of contact is instantaneously at rest.

Let us first understand pure translational and pure rotational motions.

• Pure Translational Motion

An object in pure translational motion has all its points moving with the same velocity as its center of mass i.e. they all have the same speed and direction or V(r) = Vcenter of mass. In the absence of an external force, the object would move in a straight line.

An object in pure rolling motion has all its points moving at right angles to the radius (in a plane that is perpendicular to its rotational axis). The speed of these particles is directly proportional to their distance from the axis of rotation. Here V(r) = r * ω. Here ω is the angular frequency. Since at the axis r is 0 hence particles on the axis of rotation do not move at all whereas points at the outer edge move with the highest speed.

• The points on either side of the axis of rotation move in opposite directions.

• Vpoint of contact = 0 i.e. the point of contact is at rest.

• The velocity of the center of mass is Vcenter of mass = R * ω.

• The point farthest from the point of contact move with a velocity of

Vopposite the point of contact = 2 * Vcenter of mass = 2 * R * ω.

Heave and Pitch

A ship on the sea has 6 different kinds of motions called:

This is a linear motion along the vertical z-axis.

This is also a linear motion along the transverse Y-axis.

It is again a linear motion along the longitudinal x-axis.

This is a rotational motion around a longitudinal axis.

This is a rotational motion around the transverse axis.

This is a rotational motion around the vertical axis.

Mechanical Energy is Conserved in Rolling Motion

As per the rolling motion definition, a rolling object has rotational kinetic energy and translational kinetic energy. If the system requires it, it might also carry potential energy. If we include the gravitational potential energy also then we get the total mechanical energy of a rolling object as:

Etotal = (½ * m * V2center of mass) + (½ * Icenter of mass * ω2) + (m * g * h).

When there are no nonconservative forces that could take away the energy from the system in the form of heat, an object’s total energy in rolling motion without slipping is constant throughout the motion. When the object is slipping them energy is not conserved since there is a heat production due to kinetic friction and air resistance.

Moment of Inertia

Rotational inertia is a property of rotating objects. It is the tendency of an object to remain in rotational motion unless a torque is applied to it.

If a force F is exerted on a point mass m at a distance r from the pivot point, then the point mass obtains an acceleration equal to F/m in the direction of F. Since F is perpendicular to r in the case above, the torque τ = F * r. The rotational inertia is given by the formula m * r².

Parallel Axis Theorem

If the rotational axis passes through the center of mass, then the moment of inertia is minimal. Moment of inertia increases as the distance of the axis of rotation from the center of mass increases. As per the parallel axis theorem, the moment of inertia about an axis that is parallel to the axis across the object’s center of mass is given by the below formula:

Iparallel axis = Icenter of mass + M * d2

Where d is the distance of the parallel axis of rotation from the center of mass.

Let us understand this with an example: Let there be a uniform rod of length l having mass m, rotating about an axis through its center and perpendicular to the rod. What is the moment of inertia Icenter of mass?

Solution. Moment of inertia of a rod = ⅓ * m * l2

Distance of the end of the rod from its center = l/2

Hence the parallel axis theorem of the rod = ( ⅓ * m * l2) – m * (l/2)2)

                = ( ⅓ * m * l2) – ( ¼  * m * l2) 

Icenter of mass = 1/12 * m * l2

What is Schottky Diode? 

A Schottky diode, widely popular as barrier diode, refers to a metal-semiconductor diode that comprises lower voltage drops than usual PN-junction diodes. On top of that, it possesses a fast switching speed. 

Their advantage includes the fact that their forward voltage drop is significantly lower than PN-junction diodes. It is because they constitute a metal electrode that links with N-type semiconductor. Contrarily, a PN-junction diode comprises P-type material and N-type material. 

In this case, a P-type semiconductor refers to an intrinsic or pure semiconductor, such as silicon or germanium. In this case, one has to add a trivalent impurity. These trivalent impurities include Boron (B), Gallium (Ga), Indium (In), and Aluminum (Al). These are also acceptor impurities. 

On the other hand, N-type materials refer to the integration of phosphorus, arsenic, antimony, and bismuth to pure semiconductors. 

How Does a Schottky Diode Function? 

A diode in this category functions as per the Schottky diode theory. It states that an essential factor in its functioning is fast switching rate and considerably lower voltage drop. 

Also, it lacks the propensity to store electrical charges at their diode junctions. One of the reasons that enable its working is the overall lack of a depletion layer. In most cases, when current passes through a diode, the terminals witness a drop in voltage. 

The drop conventionally ranges between 0.15 and 0.45 volts as opposed to an ordinary PN-junction diode. In the case of the latter, the spectrum of voltage drop is 0.6 to 1.7 volts. It happens mainly because current advances in a forward direction

Schottky diode working leverages the low voltage drop to generate a higher efficiency and output. For this to happen, the N-type semiconductor has to function as a cathode. The metal assumes the role of an anode. 

What is Schottky Diode Symbol? 

The following diagram represents the Schottky diode symbol – 

[]

In the above diagram, the anode section is essentially a metal, such as molybdenum, chromium, tungsten, or platinum. On the other hand, n-type semiconductors such as the integration of silicon and bismuth stand for the cathode section. 

What is Schottky Diode Construction? 

The following figure is a pictorial representation of Schottky diode construction and working –

[]

In this figure, you can see that a lightly doped n-type semiconductor connects to a metal electrode or the anode. Here, you can refer to the connection as ‘metal-semiconductor junction’. When current flows in a forward direction, electrons travel from the n-type material end to the metal anode. 

The drift of majority charge carriers heavily influences the overall current component passing through this category of a diode. However, such diodes also exhibit the properties of a rectifying diode. 

The primary reason behind this is that diode conduction ceases and blocks the flow of current.  It is due to the absence of p-type semiconductor. As a result, these diodes respond rapidly to reverse bias alterations. 

What are the Characteristics of a Schottky Diode? 

Since you know what is Schottky diode and its construction, it is time to move on to its characteristics. 

Therefore, Schottky diode characteristics are as follows – 

• When compared with conventional PN-junction diodes, these diodes exhibit significantly lower drops in forward voltage. 

• Forward voltage drops vary between 0.15 and 0.45 volts, as opposed to 0.6 to 1.7 volts in PN-junction diodes. 

• Forward drop in these diodes increases with the enhancement of doping concentration of N-type semiconductors. 

• The drop in forward voltage in a Schottky barrier constitutes semiconductors such as Silicon. 

• Besides, these also act as a unipolar device owing to the lack of current flow from metals to N-type conductors. 

• The implemented metals do not undergo charge storage. As a result, these switch considerably quickly with a minimum noise component. 

Furthermore, Schottky diode applications include the following – 

• Implementation in the electronics industry due to its properties as a general diode rectifier. 

• Radio Frequency (RF) applications also find broad uses of this technology. 

• These also find application in signal detection and logic circuits. 

What are the Disadvantages of a Schottky Diode? 

Despite its various uses,there are a few disadvantages of Schottky diodes. This includes – 

Since you are now aware of what is Schottky diode, you should check out related concepts to know a lot more about this subject. You can also download our app to avail a convenient and interactive learning experience. 

A semiconductor, as the name mentions, is an element that bears partial conducting ability. A semiconductor does neither fit itself under the category of conductors nor under the category of the insulator. Generally, some impurities are always added to the semiconductor for the best results. This process is commonly termed doping. Based on the type of impurity, semiconductors are further categorized into two types- a) p-type semiconductor (positively charged) and b) n-type semiconductor (negatively charged). P and N-type semiconductors have limited usage when they are used in isolation. But when we make a collaborative usage for both p and n-type semiconductors, it is called a p-n junction.

When a p-n junction is affixed to some external voltage provider, for instance, a battery, the complete set-up will be known as a Semiconductor Diode. Though the entire set-up is bi- terminal, the passage of current is unidirectional.

Types of Semiconductors

Semiconductors are classified under two heads based on the connection used:-

• Semiconductor Diode Forward Bias: It is a very well-known fact that a battery has two terminals- a positive terminal and the other negative one. So, when the semiconductor’s N and P end is fixed with the negative and positive sides of the battery, respectively, the set-up is coined as Semiconductor Diode forward bias. Since the negative extreme will drive away free electrons in the front of the junction, and the P end of the semiconductor will thrust the holes, they will merge at the junction. But free electrons coming out of the battery will penetrate the N region, and the valence electrons abandon the P region, thus creating a movement of current.

• Semiconductor Diode Reverse Bias: As the name suggests, it is just the opposite concept of forwarding bias. Now, the semiconductor’s N side is affixed with the positive end of the battery. This entire set-up is known as Semiconductor Diode reverse bias. The electrons that arise from the N side of the semiconductor will be directed along with the positive terminal of the battery. The negative terminal will drive the holes away from the junction. The holes and electrons do never meet at the junction, and there is a clog of current in this setup. As we can see, the majority current does not flow in the reverse bias. Instead, there is a reverse flow of current in this situation due to minority carriers.

Symbol of the Circuit

There are certain symbols used to express an electrical circuit. Following the above discussions, we can create a symbol of the Semiconductor Diode. It is represented as:- 

Semiconductor Diode Characteristics

There is a graphical representation of the voltage and current, as applied in the case of Semiconductor Diode forward bias and Semiconductor Diode reverse bias. When a forward bias is raised, we also observe a rise in current up to a stable voltage called knee voltage in a linear fashion. But after this voltage, the current differs in a non-linear way. 

As we know, reverse current does not depend on the reverse bias. Rather this current depends on the temperature of the junction. It is calculated that the current multiplies to the extent of 7% for every 1-degree rise in temperature.

Zener Breakdown

If the reverse bias is raised to a large extent, the electric field also gets expanded, which in turn creates a huge number of electrons and holes. It is defined as a Zener breakdown.

Dynamic Resistance

It is explained as the ratio of minor changes in the voltage to the ratio of minor changes in the current. It is expressed in the form of rd. Therefore the numerical expression of voltage resistance is r_d = [frac {Delta V} {Delta I}]

Numerical:- A diode is made constant in a circuit. The voltage falls by 0.5 V, and the highest power marked is 100 mW. What should be the value of the resistor R, which is attached in series to this diode?

Solution:- Current that flows among the diode the, I = [frac {Power} {Voltage}]

Therefore, I= [frac {(100 times 10^-3)} {0.5V}]

 (as we know 1mW= 10-3 W)

= 0.2 A

Resistance=Net Voltage/Current [frac {Net Voltage} {Current}]

= [frac { (1.5−0.5)} {0.2}]

 = 5 Ohm.

The devices made from semiconductors have very much eased our lives. There are different types of diodes like the Semiconductor Diode that are used in many devices. So, it becomes important for us that we know about these devices in detail. The motive of this article is the same i.e it is meant to give you in-depth detail on the Semiconductor Diode. You will be able to study the definition of Semiconductor Diode, its different characteristics and its symbol.

Diode

A diode is a semiconductor device made up primarily of silicon components. The anode, which is inherently positive and has a lot of holes, is positioned next to the cathode, which is negatively charged and contains a lot of electrons. A depletion area forms at this point, with no holes or electrons. A positive anode voltage causes the depletion region to be small, allowing current to flow; a negative anode voltage causes the depletion region to be big, prohibiting current flow.

A diode is a two-terminal electrical component that conducts electricity mostly in one direction. It has a strong resistance on one end and a low resistance on the other.

To limit the voltage across circuits or to convert AC into DC, diodes are used. They also serve to safeguard the circuits. The most common semiconductors used to manufacture diodes are silicon and germanium. Although they both transport electricity, in the same way, however, how they do so, differs. Diodes are available in a range of shapes and sizes, each with its own set of uses.

Diode Construction

The two semiconductor materials that can be utilized to manufacture diodes are silicon and germanium. When the anode voltage exceeds the cathode voltage and the diode conducts readily with minimum voltage loss, it is said to be forward-biased. When the cathode voltage exceeds the anode voltage, the diode is said to be reverse-biased. The direction of conventional current flow is depicted by the arrow in the symbol.

Diode’s Symbol

The anode and cathode are the two terminals of a diode. The anode is represented by the arrowhead. In the forward-biased condition, the anode represents the traditional current flow direction. The cathode is represented by the vertical bar. 

The following are some of the most commonly used and essential diodes:

Tunnel Diode

Because of the quantum mechanical process known as tunneling, a tunnel diode (also known as an Esaki diode) has essentially zero resistance. In tunnel diodes, the PN junction is heavily doped and about 10 nm wide. The n-side conduction band electron states are more or less aligned with the p-side valence band hole levels, resulting in a broken bandgap.

Zener Diode 

The most valuable sort of diode is the Zener diode, which can provide a constant reference voltage. When a specific voltage is supplied, these are reverse biased and break down. When the current flowing through the resistor is limited, a stable voltage is formed. Zener diodes are often used in power supplies to provide a reference voltage.

LED (Light Emitting Diode)

A photodiode can detect even a little amount of current flow induced by light. Even a small amount of current flow caused by light can be detected by a photodiode. When it comes to detecting light, these are incredibly useful. Photodiodes are reverse bias diodes that are commonly found in solar cells and photometers. They’re even used in the generation of electricity.