KVL and KCL

Welcome everyone! ....                   

From today we are going to start the new chapter in our field of technology.

This subject is common and very much required for both electrical and electronics departments and it is about network theory.

And also from today an interesting fact about science or nature or health or our livelihood is also been going to be posted at the end of the topic. So stay tuned.

NETWORK THEORY  :

Network theory is the branch of electrical and electronics field which incorporates the analysis and design of circuits

Okay let us see some important terms related to network theory.

ELECTRICAL NETWORK  :

Interconnection of circuit elements is simply called an electrical network.

Node :

The junction meeting two or more branches in an electrical network is called a node.

Kirchhoff’s laws play a major role in the analysis of electrical circuits.

Kirchhoff’s law :

Gustav Kirchhoff : German physicist.

He proposed two laws which decreases the complexity and makes the analysis of interconnection of any number of circuit elements in an electrical network.

 1. Kirchhoff’s Current Law

 2. Kirchhoff’s Voltage Law

Kirchhoff’s Current Law

This law states that the algebraic sum of currents meeting the junction or node of an electrical network is zero

                                                                                      (or)

The algebraic sum of the currents entering the junction or node are equal to the algebraic sum of currents leaving the node.

                                                       

                                               I₁+I₂+I₃-I₄-I₅ = 0 …………. (1)

The above equation says that  KCL obeys the law of conservation of energy.

                                  I₁+I₂+I₃ = I₄+I_5.

Kirchhoff’s voltage law

This law states that the algebraic sum of voltages around a closed loop moving in same direction is zero.

                                                                             

                                             V₁+V₂+V₃+V₄ = 0.

This is all about KVL and KCL.

Everyday is very joyful when we learn some interesting things, so we look forward to post some useful facts on every posts...

TODAY’S FACT :

 Science day in Switzerland is dedicated to Ex - Indian President ..and a great scientist  Dr.APJ Abdul Kalam..on  May 26...really very inspirational to share this. We are all proud to share this news with you... 

Really... inspirational...                        

Thanks for visiting us... 

source transformation

SOURCE TRANSFORMATION

Welcome to everyone… till today we have met with basic theme of our blog which includes some basic concepts of electrical field and electronics.

In electrical field we have covered the introduction concepts..

     1. Introduction.

     2. Circuit elements.

     3. Energy sources.

     4. Alternating sources.

Today we are again going through electrical concepts. One of the basic concepts is source transformation i.e. any practical voltage source in series with an internal impedance can be replaced with a current source in parallel with internal impedance.this means that the voltage souce and current source are mutually transferrable.

                                                              

     

Let V be the voltage source with an internal impedance R₁ in series  and a load resistance R_L then I₁ be the  current at load terminal

                                                                   I₁= v/(R₁+R_L) …………..(1)

                                                          

Let I be the current source with an internal impedance R₂ in parallel and a load resistance R_L then the current at load terminal

                                                                I₂= I R₂/(R₂+R_L) ……….(2)

                                                                             (1) = (2)

                                                                 v/(R₁+R_L) = I R₂/(R₂+R_L)   

                                                                   (R₁+R_L) = (R₂+R_L)

                                                                             R₁ = R₂

     This concludes that any practical voltage source in series with an internal impedance can be replaced with a practical current source with the same resistance In parallel with it.     

Applications of Zener-diode

Hello friends......welcome to our blog, today we are here discuss about the applications of zener-diode. In my last post we discussed about zener-diode, hope we gave our level best to explain the topic. So today we are back with some more  confidence to go forward and give much more knowledge from our side let's go through the topic..

Applications of Zener-diode:

As we know what is zener diode and how it will work our next question is ''what are the applications of zener-diode?''

The term zener is commonly used for the avalanche, or breakdown, diode even at higher voltages.

The main application of this type of diodes are voltage regulators. 

we all know that a zener diode maintains a constant output voltage in its breakdown region even though the current flowing through it is varied in its operating region.Zener diode is used to minimize the the voltage fluctuation of a dc power supply obtained by the rectifier-filter combination this is why we use zener diode in 

voltage regulator we can simply called it as zener regulator.

The term regulator itself says that regulate means to control.

If we introduce zener diode in a circuit we can understand easily.

In the above diagram it is a shunt regulator because of the regulator element is parallel to the load.

To limit the current through the zener diode series resistance R is introduced whose value can be chosen from the following equation.

R=(V1-V2)/(zener current + load current).

We have more applications in zener diode in various fields of electronics.In our further topics we will be learn more about this.In the next topic we will discuss some more topics briefly so please stay tuned....thanks for visiting us and please share to maximum extent to better people to stay in...

Zener diode

Hello friends..welcome back to this blog.  Today we are here to present a new concept in electronics. Actually in the last topic we discussed about P-N junction diode and its V-I characteristics.We hope  from the last topic gave the knowledge and  guidance to the working of P-N junction diode and its characteristics. There are some special diodes and functioning in the diodes.Today's topic is about ZENER diode. So lets go through the topic.

Zener-diode

We all know that from P-N junction as the voltage is increased in forward bias the maximum current flows and in reverse bias a small fraction of  current flows after the breakdown voltage, so in order to use the diode in reverse bias we have a special diode i.e, ZENER diode.

 Zener diode means a form of semiconductor diode in which at a critical reverse voltage large current can flow. Zener diode is operated in reverse bias only. A zener diode is heavily doped than ordinary diode.When reverse voltage reaches breakdown voltage in normal P-N junction diode, the current through the diode and the power dissipated at the junction will be high. Such operation damages the diode.With adequate power dissipation capability to operate in breakdown region a special diode is designed which is called "Zener diode".    

Symbol of zener diode:

Zener diode is always reverse connected.When forward biased its characteristics are just like normal diode.It has sharp break down voltage called breakdown voltage.

Explanation: 

It is mainly a special property of the diode rather than any special type of equipment. The person named clearance Zener invented this property of the diode so it is named as "Zener diode". The special property of the diode is that there will be a breakdown in the circuit if the voltage applied across a reversely biased circuit.

a)V-I Characteristics of zener diode

• From the V-I characteristics of Zener diode it is found that the operation of zener diode is same as P-N junction diode in forward bias.
• Under reverse bias condition its working is changed, here breakdown of junction occurs and breakdown is sharp. The break down voltages are dependent on amount of doping.

There are two types of breakdowns

1.Zener breakdown:

                                            In zener breakdown due to heavy doping, direct rupture of covalent bond takes place because of strong electric field. Hence new electron-hole pairs are created which increases the reverse current in reverse bias.

2.Avalanche breakdown:

                                            In avalanche breakdown if reverse bias voltage increases the charge carriers acquire large amount of kinetic energy and their velocity also increases. These carriers(electrons) disturb the covalent bond by colliding with immovable ions and create new electron hole pairs. 

This was all about Zener diode.From next post we will discuss about applications of zener diodes.. so stay tuned for more updates and moreover thanks for visiting us....please follow and share us for more better people to stay in....

V-I characteristics of P-N junction diode

Hello friends we are back once again with a new post. In the last post we have given an idea about 

P-N junction diode. Today we are here to discuss about the V-I characteristics of P-N junction diode.

V-I characteristics of P-N junction diode:

In earlier we  discussed about  P-N junction diode and types of biasing. In this post we will  study the V-I characteristics. For this we have to plot  a graph for applying voltage and current.

Fig-1: V-I characteristics of P-N junction diode.

In the above figure voltage is taken on X-axis and current is on Y-axis. Here Vf indicates the forward voltage and Vr indicates the reverse voltage and If indicates forward current and Ir indicates reverse current. Knee voltage is the forward voltage at which the current through the P-N junction increases rapidly and breakdown voltage is the reverse voltage at which the current through the P-N junction slowly increases due to minority carriers. 

For forward bias:

As forward voltage is increased, the depletion layer decreases,beyond a threshold voltage the current starts conducting and that voltage is know as "cut in voltage".

Before cut in voltage the curve is non linear. After applying voltage more than cut in voltage the current starts flowing due to depletion layer decreases and the curve after cut in voltage is linear.

For reverse bias:

In fig-1 as the reverse bias is increased the width of depletion layer increase, beyond a breakdown voltage small current flows due to minority carriers flows through the diode.If reverse voltage is further increased the kinetic energy of electrons becomes so high. The knockout of electrons from semiconductor occurs at this case breakdown of junction is occur.

This is all about the V-I characteristics of P-N junction diode.Next we will discuss a new topic in this chapter. Thanks for visiting us stay tuned for more updates  please follow and share to the maximum extent for a better people to stay in..

Biasing of P-N junction diode

Hi  friends we are back once again with a new concept in this electronics.Actually in our last post we gave introduction to electronics and P-N junction diode. Today's post is about biasing of PN-junction diode.

Biasing of P-N junction diode:

• As we discussed earlier that  P-N junction represents two blocks of semiconductor materials , one p-type and one n- type material. On the formation of P-N junction some of the holes from p-type material tend to diffuse across the boundary into n-type material and some of the free electrons similarly diffuse into p-type material.
• A P-N junction diode is connected to an external voltage source, it is called biasing P-N junction diode.
• Biasing is used to control the width of depletion layer 

There are two types of biasing:

• 1)Forward bias
• 2)Reverse bias

1)Forward bias:

In forward bias P-type is connected to positive terminal and N-type is connected to negative terminal of the battery.

When voltage is applied across a diode in such a way that the diode allows current, the diode is said to be forward-biased

• When we apply the external voltage in such a way that it cancels the potential barrier and permits the current to flow. 
• By application of small voltage it is sufficient to eliminate the barrier so the width of the diffusion layer decreases and becomes zero(0) and junction is formed and holes takes place.

2)Reverse bias:

In reverse bias P-type is connected to negative terminal and N-type is connected to positive terminal of the battery.

"When voltage is applied across a diode in such a way that the diode prohibits current, the diode is said to be reverse-biased. "

• When we apply the external voltage in such a way that it increases the potential barrier width and prohibits the current to flow through them.
• Due to minority charges small current flows in reverse bias which is know as reverse saturation current.

This is all about biasing of P-N junction diode.  In our next chapter we will discuss more deeply about characteristics and types of diodes so please stay tuned for more updates and more over thanks for visiting us please follow and share to maximum extent for better people to stay in..

P-N JUNCTION

A very warm welcome to everyone in this very cool day. In the previous session we have started the basics of electronics , in that we have stated that semiconductor devices plays a major role in electronics concepts. By considering that today we are going to discuss about the concept of P-N junction diode

Before going to the topic ,let us see some important terms regarding semi conductors.

1.Doping :
Addition of impurity atoms to intrinsic semiconductor crystal is called doping and the impurity used is called dopant.

2.Diffusion : The process of doping a semiconductor with impurities is called diffusion.

3.Donor : Any pentavalent impurity used as dopant to produce N-type semiconductor is called donor.
Arsenic,antimomy etc.,

4.Acceptor : Any trivalent impurity used as dopant to produce P-type semiconductor is called acceptor.

P-N junction :
Basically every semiconductor material has majority and minority carriers.

        a.P-type material :
             Majority carriers - holes.
             Minority carriers - electrons.

          b.N-type material :
              Majority carries - electrons.
              Minority carriers - holes.

P-N junction represents two blocks of semiconductor materials , one p-type and one n- type material. On the formation of P-N junction some of the holes from p-type material tend to diffuse across the boundary into n-type material and some of the free electrons similarly diffuse into p-type material.

This is happend because of concentration of holes is higher on p-side than that of n- side and vice-versa.This process is called diffusion.

The region around the junction is completely ionised .As there are no free electrons on N-side and there are no holes on p-side . Since the region around the junction is depleted of mobile charges it is called the depletion region , space charge region or the transition region.
The thickness of the depletion region is of the order of one micron.

Today I have provided some concept regarding P-N junction in the next post I will describe about different types of biasing and characteristics....

If you want to be powerful, educate yourself....
Thank you.. 
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