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# JEE Important Chapter - Electronic Devices

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## A Detailed Information About Electronic Devices For JEE Preparation

Last updated date: 18th Mar 2023
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A smart way of preparation will help students in securing good grades in competitive exams like IIT-JEE and JEE-Main. ‘Electronic devices’ is one such important chapter that will definitely help students in securing good scores and boost their grades in the upcoming exams.

The electronic devices chapter introduces us to what is electronics and the types of electronics. The chapter includes the concepts of semiconductor physics. In this chapter, students will have exposure to the concepts of the conduction of electrons in different material types. We study the differences between the conductor, semiconductor and insulators with the help of the energy gap between the covalent and valence band. Further, in this chapter, we study the semiconductor and types of semiconductors classification depending on the doping method (Intrinsic and Extrinsic).

In electronic devices, we study a few most important semiconductor devices such as diodes, and transistors in detail. At last, we will be moving towards digital electronics which is the fundamental and most interesting part of the chapter.

In this article, students will be provided with the content that will be a helping aid for their preparation. Let's start!!

## JEE Main Physics Chapter-wise Solutions 2022-23

### Important Topics of Electronic Devices

• Semiconductors

• Energy Bands In Solids

• Classification of Materials

• PN-Junction diode

• Biasing Techniques

• PN-Junction Diode As A Rectifier

• Zener Diodes

• Transistors-NPN and PNP

• Transistor As an Oscillator

• Logic Gates

• De Morgan Theorems

### Important Concepts of Electronic Devices

 Sl. No Concept Name Key Points 1. Energy Bands in Solids Valence Band: It is the band formed by the outermost electrons (valence electrons) which are strongly bound to the nuclei.Conduction Band: It is the band formed by the free electrons (conduction electrons) which are loosely bound to the nuclei. 2. Forbidden Energy Gap Energy gap in any solid is the separation between the conduction and valence band 3. Classification of materials Conductors: These are the semiconductor materials in which there will be a very small energy gap or no energy gap between the CB and VBInsulators: These are the solid materials in which the energy bandgap will be large enough, such that conduction will not be taking place.Semiconductors: These are the materials whose conductivity lies between conductors and insulators. The energy gap between these will be small but more than the conductors. Some of the Semiconductor electrical devices examples are transistors, diodes, etc… 4. Types of Semiconductors Intrinsic Semiconductors: Intrinsic semiconductors are the pure form of semiconductors. Ge and Si are examples.Extrinsic Semiconductors: These are the type of semiconductors in which impurities will be added. Extrinsic semiconductors are further classified as N-type and P-type semiconductors. 5. N-type and P-type Semiconductors N-type: These are the semiconductors formed by adding pentavalent impurities to the pure semiconductor. Here, electrons will be the majority charge carriers.P-type: These are the semiconductors formed by adding trivalent impurities to the pure semiconductors. Here, holes will be the majority charge carriers. 6. PN-Junction Diode It is a two-terminal electronic device that helps in regulating the flow of electric current.The symbol of the PN-Junction diode is: 7. Biasing Methods Forward biasing: If the positive terminal of an electronic device is connected to the positive and negative terminal, the negative terminal of the battery is known as forward biasing.Reverse biasing: If the positive terminal of an electronic device is connected to the negative and negative terminal connected to the positive terminal of the battery is known as reverse biasing. 8. Diode As a Rectifier Rectifiers: These are the electronic devices used for converting alternating current into direct current. 9. Half Wave Rectifier Only half part of the ac signal will be rectified. 10. Full Wave Rectifier The complete cycle of the ac signal will be converted into a dc signal. 11. Transistors These are the three-terminal electronic devices used for the amplification process.Transistors consist of an emitter, base and collector.A transistor is made by sandwiching two pn-junction diodes back to back.There are two types of transistors PNP and NPN, depending on the majority charge carriers. 12. Logic gates Logic gates are the building blocks of digital electronics. The logic gates are basically the devices used to perform mathematical operations using bits 0 and 1. Logic gates are two or more inputs and single output devices.There are three basic gates: OR, AND and NOT.Two universal gates: NAND Aand NOT 13. Basic Logic Gates OR Gate: These are the logic gates used to perform addition.Boolean expression: Y= A+BAND Gate: These are the logic gates used to perform multiplication.Boolean expression: Y= ABNOT Gate: These are the logic gates used to perform complementary functions.Boolean expression: $Y=\bar A$ 14. Universal Logic Gates NAND Gate: It is the combination of NOT and AND gates.$Y= \bar {AB}$NOR Gate: It is the combination of NOT and OR gates.$Y=Y=\overline{A+B}$

### List of Important Formulae in Electronic Devices

 Sl. No Concept Name Formula 1. Mass Action Law The product of the concentrations of free electrons 'ne' and holes 'nh' is a constant in thermal equilibrium, and it is independent of the amount of doping by acceptor and donor impurities.${n_e}\times {n_h}={n_i}^2$ 2. Form Factor For Full Wave Rectifier:$F=\dfrac {\pi}{2\sqrt {2}}$For Half Wave Rectifier:$F=\dfrac {\pi}{2}$ 3. RMS Value of Current $I_{rms}=\sqrt {{I_{dc}}^2 +{I_{ac}}^2}$ 4. Ripple Factor $r=\dfrac {I_{ac}}{I_{dc}}=\sqrt {{F^2}-1}$ 5. Electrical conductivity of semiconductors Intrinsic semiconductor:-σ = e(neμe + nhμh)$\sigma={\sigma_o}e^{\dfrac {E_g}{kT}}$Extrinsic semiconductor:-N-type: σ = eneμeP-type: σ = ennμn 6. Transistors Relation between the currents in the transistors:IE=IC+IB (IB << IE, IB<

### Solved Examples

1. Draw and explain the output waveform across the load resistor R, if the input waveform is as shown in the given figure.

Sol:

Given,

A square wave is used as a signal, now we are asked to determine the output waveform when the signal is passed through the load resistor R.

Here, we will consider two different conditions:

1. When the input signal +5V:

With +5 V input, the pn-junction diode will be forward biased and +5 V voltage will pass through the load resistance.

1. When the input signal -5V:

With -5 V input, the pn-junction diode will be reverse biased and no voltage will pass through the load resistance.

Therefore, the output waveform will be as shown below:

Key Point: When the pn-junction diode is reverse biased the voltage across the resistor will be zero.

1. In an unbiased p-n junction diode, holes tend to diffuse from the p-region to n-region, due to

1. hole concentration in p-region is more as compared to n-region.

2. they move across the junction by the potential difference.

3. free electrons in the n-region attract them.

4. All the above

Sol:

The right answer is option a.

Reason: In an unbiased pn junction diode, holes tend to diffuse from the p-region to n-region, because, in p-region is having abundant holes which will attract the electrons in the n-region.

Key point: The charge carriers always move from higher concentration to lower concentration. In this question, we can see that p-region having more number of holes than in n-region.

### Previous Year Questions From Electronic Devices

1. Identify the logic operation carried out by the given circuit

1. OR

2. AND

3. NOR

4. NAND

Sol:

Given,

On analysing the logic circuit we found that,

$Z=\bar {A}. \bar {B}=\overline{A+B}$= NOR gate

Therefore, Option C is the right answer.

Trick: Whenever we come across a complimentary function we should remember that De morgan’s theorem will solve the equation easily.

1. For the given circuit, the power across zener diode is ………..mW.

Sol:

Given, an electric circuit with zener diode. Now we are asked to determine the power across the zener diode.

Let us solve the circuit first:

$I_L=\dfrac {10}{5}=2 mA$

I=141=14 mA$I=\dfrac {14}{1}=14 mA$

$I_Z=I-{I_L}=14-2=12 mA$

Therefore, power across zener diode is:

$P_Z = {I_Z}{V_Z}=12 mA \times 10=12o mW$

Trick: Voltage across the parallel components will always be equal.

### Practice Questions From Electronic Devices

1. In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always present

1. None of these

2. such that number of holes is greater than the number of electrons

3. in equal numbers

4. such that number of electrons is greater than the number of holes

(Ans: Option C)

1. When Ge crystal is doped with phosphorus atoms, it becomes

1. superconductor

2. Insulator

3. n-type

4. p-type

(Ans: Option C)

### Conclusion

In this article, we have gone through the most important concepts of electronic devices. We have seen a few solved examples which are tricky yet simple to tackle. We can see that there are many applications of electronics in terms of various devices with different purposes. In this article, we have also added a few important questions from previous year's question papers. Students are required to solve more and more questions to ace the exam.

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## JEE Main Important Dates

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JEE Main 2023 January and April Session exam dates and revised schedule have been announced by the NTA. JEE Main 2023 January and April Session will now be conducted on 24-Jan-2023 to 31-Jan-2023 and 6-Apr-2023 to 12-Apr-2023, and the exam registration closes on 12-Jan-2023 and Apr-2023. You can check the complete schedule on our site. Furthermore, you can check JEE Main 2023 dates for application, admit card, exam, answer key, result, counselling, etc along with other relevant information.
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## JEE Main Information

Last updated date: 18th Mar 2023
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Application Form
Eligibility Criteria
Reservation Policy
Exam Centres
NTA has announced the JEE Main 2023 January session application form release date on the official website https://jeemain.nta.nic.in/. JEE Main 2023 January and April session Application Form is available on the official website for online registration. Besides JEE Main 2023 January and April session application form release date, learn about the application process, steps to fill the form, how to submit, exam date sheet etc online. Check our website for more details. April Session's details will be updated soon by NTA.

## JEE Main Syllabus

View JEE Main Syllabus in Detail

Last updated date: 18th Mar 2023
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It is crucial for the the engineering aspirants to know and download the JEE Main 2023 syllabus PDF for Maths, Physics and Chemistry. Check JEE Main 2023 syllabus here along with the best books and strategies to prepare for the entrance exam. Download the JEE Main 2023 syllabus consolidated as per the latest NTA guidelines from Vedantu for free.
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View JEE Main Syllabus in Detail

## JEE Main 2023 Study Material

View all study material for JEE Main
JEE Main 2023 Study Materials: Strengthen your fundamentals with exhaustive JEE Main Study Materials. It covers the entire JEE Main syllabus, DPP, PYP with ample objective and subjective solved problems. Free download of JEE Main study material for Physics, Chemistry and Maths are available on our website so that students can gear up their preparation for JEE Main exam 2023 with Vedantu right on time.
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## JEE Main Question Papers

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Download JEE Main Question Papers & ​Answer Keys of 2022, 2021, 2020, 2019, 2018 and 2017 PDFs. JEE Main Question Paper are provided language-wise along with their answer keys. We also offer JEE Main Sample Question Papers with Answer Keys for Physics, Chemistry and Maths solved by our expert teachers on Vedantu. Downloading the JEE Main Sample Question Papers with solutions will help the engineering aspirants to score high marks in the JEE Main examinations.
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## JEE Main 2023 Book Solutions and PDF Download

View all JEE Main Important Books

Last updated date: 18th Mar 2023
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In order to prepare for JEE Main 2023, candidates should know the list of important books i.e. RD Sharma Solutions, NCERT Solutions, RS Aggarwal Solutions, HC Verma books and RS Aggarwal Solutions. They will find the high quality readymade solutions of these books on Vedantu. These books will help them in order to prepare well for the JEE Main 2023 exam so that they can grab the top rank in the all India entrance exam.
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Maths
NCERT Book for Class 12 Maths
Physics
NCERT Book for Class 12 Physics
Chemistry
NCERT Book for Class 12 Chemistry
Physics
H. C. Verma Solutions
Maths
R. D. Sharma Solutions
Maths
R.S. Aggarwal Solutions
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## JEE Main Mock Tests

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JEE Main 2023 free online mock test series for exam preparation are available on the Vedantu website for free download. Practising these mock test papers of Physics, Chemistry and Maths prepared by expert teachers at Vedantu will help you to boost your confidence to face the JEE Main 2023 examination without any worries. The JEE Main test series for Physics, Chemistry and Maths that is based on the latest syllabus of JEE Main and also the Previous Year Question Papers.
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## JEE Main 2023 Cut-Off

JEE Main Cut Off

Last updated date: 18th Mar 2023
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NTA is responsible for the release of the JEE Main 2023 January and April Session cut off score. The qualifying percentile score might remain the same for different categories. According to the latest trends, the expected cut off mark for JEE Main 2023 January and April Session is 50% for general category candidates, 45% for physically challenged candidates, and 40% for candidates from reserved categories. For the general category, JEE Main qualifying marks for 2021 ranged from 87.8992241 for general-category, while for OBC/SC/ST categories, they ranged from 68.0234447 for OBC, 46.8825338 for SC and 34.6728999 for ST category.
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## JEE Main 2023 Results

Last updated date: 18th Mar 2023
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NTA will release the JEE Main 2023 January and April sessions exam dates on the official website, i.e. {official-website}. Candidates can directly check the date sheet on the official website or https://jeemain.nta.nic.in/. JEE Main 2023 January and April sessions is expected to be held in February and May. Visit our website to keep updates of the respective important events of the national entrance exam.
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Rank List
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JEE Main 2023 state rank lists will be released by the state counselling committees for admissions to the 85% state quota and to all seats in IIT colleges. JEE Main 2023 state rank lists are based on the marks obtained in entrance exams. Candidates can check the JEE Main 2023 state rank list on the official website or on our site.

## JEE Top Colleges

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Last updated date: 18th Mar 2023
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Want to know which Engineering colleges in India accept the JEE Main 2023 scores for admission to Engineering? Find the list of Engineering colleges accepting JEE Main scores in India, compiled by Vedantu. There are 1622 Colleges that are accepting JEE Main. Also find more details on Fees, Ranking, Admission, and Placement.
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## FAQs on JEE Important Chapter - Electronic Devices

FAQ

1. Is Semiconductor devices a simple chapter for JEE?

Semiconductors and communication are relatively challenging to deal with. Certain factors must be kept in mind, and your concepts must be clear. You must also memorise a few things in addition to understanding the material. It is a crucial chapter for jee main, and students should study it thoroughly.

2. What is the importance of the electronic devices chapter for JEE?

Minimum of 2-3 questions will appear from this chapter, which covers 3% of the JEE total score. One of the easiest chapters of physics to score in JEE.

3. How to prepare the electronic devices chapter?

Students must prepare for the electronic devices by solving previous year's questions and NCERT solutions.

## JEE Main Upcoming Dates

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JEE Main Exam April Session Starts
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JEE Main Exam April Session Ends
12 May 202352 days remaining

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