LESSON PLAN
Section 2 Topic 2.5 Semiconductor devices
(Lesson topic)
Full name (full name)
Diligenskaya Yulia Vladimirovna
Place of work
BPOU VO "Cherepovets Forestry Mechanical College named after. V.P. Chkalov"
Job title
Teacher
Professional module PM 01. Organization of maintenance and repair of electrical and electromechanical equipment
MDK 01.05 Typical electrical circuits and functional units of electronic and computing devices
ELEMENTS OF ELECTRONIC CIRCUITS
Literature
Main
1. Tugov N. M., Glebov B. A., Charykov N. A. Semiconductor devices - M.: Publishing center "Academy," 2004.-240 p.
2. Miklashevsky S.P., Industrial elements of electronic circuits. M: Higher School, 2006-214 p.
Information
1.Diodes, transistors, optoelectronic devices: Directory , M.: Publishing center "Academy," 2005
2. Didactic material on general electrical engineering with the basics of electronics, Textbook - M: Higher School. 2006 – 108 s
5.Purpose of the lesson:
To familiarize students with the types of semiconductor devices;
Give an idea of the functional purpose of each device;
Show the practical significance of semiconductor devices in the specialty.
6. Tasks:
- educational
help students study the classification of semiconductor devices;.
-developing
develop students' cognitive interest.
-educational
to cultivate the information culture of students.
7.Lesson type – mastering new knowledge
8. Forms of student work – individual and group.
9. Necessary technical equipment – multimedia teacher's computer, video projector,
Lesson structure and flow
Table 1.
TECHNOLOGICAL LESSON MAP
Lesson stage
Name of EORs used
(indicating the serial number from Table 2)
Teacher's activities
Student activities
Time
(per minute)
Organizational and motivational
1. Computer device diagram
Greets students. Checks students' preparation for the lesson and completion of homework.
Formulates the topic of the lesson and reveals the objectives of the lesson.
Asks questions to motivate students to study a new topic:
What types of electronic circuits do you know?
What types of semiconductor devices do you know?
List the characteristics of semiconductor materials?
Summarizes student responses, moving on to the main part of the lesson.
They greet the teacher and show their homework in their notebooks.
Listen and comprehend the goals of the lesson, write down the date and topic of the lesson in notebooks
They answer the questions asked.
Analyze the information presented on the slide.
Main part:
Stage of transfer of new knowledge
2. Basic devices of semiconductor devices
3. Diode characteristics
4.Characteristics of transistors
5. Characteristics of microcircuits
Lecture. (Demonstration of interactive presentation)
Draws attention to the differences in the purpose and characteristics of semiconductor devices using a video fragment.
Indicates the design of semiconductor devices by displaying a diagram showing the main functional components. semiconductor devices
Talks about everyone
semiconductor device
1) Diodes
Draws attention to the fact that the properties of semiconductor materials are based on the general principles of operation of devices
2) Transistors.
3) Microcircuits.
Listen to an explanation of new material and make notes in notebooks.
Make sense of new information.
Study the presented diagram and ask questions.
Draw diagrams in notebooks.
Discuss the information presented on the slide, demonstrate their knowledge from the discipline “Physics” on the characteristics of semiconductor devices
Stage of assimilation of new knowledge
7. Application of semiconductor devices in the specialty
Offers to independently study the concept and purpose:
4) Field-effect transistors in switching equipment.
Working with a textbook, making notes in notebooks. After studying this material, unclear points become clear.
Consolidating new material
The group is divided into teams. The teacher distributes cards to each team with key words that need to be supplemented with terms related to the topic of the lesson.
Checks that the task is completed correctly
Each team works on a task, trying to complete it first.
Lesson summary
Evaluates student activities. Summarizes the overall lesson.
Assigns homework.
Thanks students for the lesson.
Listen and comprehend the results of the lesson. Record homework in diaries. Express their attitude towards the lesson.
Lesson topic: "Semiconductor devices. Diodes"
Purpose and objectives of the lesson:
Educational:
formation of an initial concept of the purpose, action and main properties of semiconductor diodes.
Educational:
to form a culture of mental work, the development of personal qualities - perseverance, determination, creative activity, independence.
Educational:
learning to use the property of one-way conductivity.
Material and technical equipment of the lesson:
workbooks, teacher’s computer, interactive whiteboard, presentation on the topic
Progress of the lesson:
1. Organizational point:
(Task: creating a favorable psychological mood and activating attention).
2. Preparation for repetition and generalization of the material covered
What is electric current?
Current strength, units of measurement.
p – ntransition.
Semiconductors.
State the topic and purpose of the lesson.
Semiconductors. Diodes.
Explanation of perspective.
To study modern electronics, you must first of all know the design principles and physical basis of the operation of semiconductor devices, their characteristics and parameters, as well as the most important properties that determine the possibility of their use in electronic equipment.
The use of semiconductor devices provides enormous savings in the consumption of electrical energy from power sources and makes it possible to reduce the size and weight of equipment many times over. The minimum power to power a vacuum tube is 0.1 W, and for a transistor it can be 1 μW, i.e. 100,000 times less.
3. Main stage.
New material
All substances found in nature are divided into three groups according to their electrical conductive properties:
Conductors,
insulators (dielectrics),
semiconductors
Semiconductors include many more substances than conductors and insulators. In the manufacture of radio devices, the most widely used are 4-valence germanium Ge and silicon Si.
The electric current of semiconductors is determined by the movement of free electrons and so-called “holes”.
Free electrons leaving their atoms create n-conductivity (n is the first letter of the Latin word negativus - negative). Holes create p - conductivity in the semiconductor (p is the first letter of the Latin word positivus - positive).
In a pure conductor, the number of free electrons and holes is the same.
By adding impurities, it is possible to obtain a semiconductor with predominantly electron or hole conductivity.
The most important property of p- and n- semiconductors is one-way conductivity at the junction. This junction is called a p-n junction.
Add 5-valence arsenic (antimony) to a 4-valence crystal of germanium (silicon), and we get an n - conductor.
By adding 3-valent indium, we get p - conductor.
When the “plus” of the source is connected to the p-region, the transition is said to be turned on in the forward direction, and when the minus of the current source is connected to the p-region, the transition is said to be turned on in the reverse direction.
The one-way conductivity of the p and n junction is the basis for the operation of semiconductor diodes, transistors, etc.
Having an understanding of the semiconductor, now let's start studying the diode.
The prefix "di" means two, indicating two adjacent zones of different conductivity.
Bicycle tire valve (nipple). Air can pass through it only in one direction - into the chamber. But there is also an electric valve. This is a diode - a semiconductor part with two wire leads at both ends.
By design, semiconductor diodes can be planar or point.
Planar diodes have a large electron-hole junction area and are used in circuits in which large currents flow.
Point diodes are characterized by a small area of the electron-hole junction and are used in circuits with low currents.
Symbolic graphic designation of a diode. The triangle corresponds to the p-region and is called the anode, and the straight line segment, called the cathode, represents the n-region.
Depending on the purpose of the diode, its UGO may have additional symbols.
The main parameters by which diodes are characterized.
Forward diode current.
Diode reverse current.
Fixing the material.
Changing the polarity of the power source connection in a circuit containing a semiconductor diode.
We connect in series the 3336L battery and an MH3.5 - 0.28 incandescent light bulb (for a voltage of 3.5V and an incandescent current of 0.28A) and connect this circuit to an alloy diode from the D7 or D226 series so that positive is supplied to the anode of the diode directly or through the light bulb, and to cathode – negative battery voltage (Fig. 3, Fig. 4). The light bulb should be fully lit. Then we change the polarity of the connection of the “battery - light bulb” circuit to the reverse (Fig. 3, Fig. 4). If the diode is working, the light does not light. In this experiment, the incandescent light bulb performs a dual function: it serves as an indicator of current in the circuit and limits the current in this circuit to 0.28A, thereby protecting the diode from overload. In series with the battery and the incandescent light bulb, you can connect another milliammeter for a current of 300...500 mA, which would record the forward and reverse current through the diode.
4. Check point:
Draw a diagram of an electrical circuit consisting of a direct current source, a micromotor, 2 diodes, so that using switches you can change the direction of rotation of the micromotor rotor.
Determine the poles of a flashlight battery using a semiconductor diode.
Study diode conductivity yourself on a demonstration stand. Study of one-way conductivity of a diode.
5. Final point:
assessment of success in achieving the objectives of the lesson (how they worked, what they learned or learned)
6. Reflective moment:
determining the effectiveness and usefulness of a lesson through students’ self-assessment.
7. Information point:
determining the prospects for the next lesson .
8. Homework
To consolidate the material covered, think about the following problems and provide their solution:
How to protect radio equipment from polarity reversal using a semiconductor diode?
There is an electrical circuit that includes four series-connected elements - two light bulbs a and b and two switches A and B. In this case, each switch lights only one, only “its” light bulb. In order to light both bulbs, you need to close both switches at the same time.
Physics lesson 11th grade
Lesson topic:
“Semiconductors.
Intrinsic and impurity conductivity of semiconductors. Electric current in semiconductors"
The purpose of the lesson
Materials and equipment:
Computer, projector, electronic materials on the topic: “Semiconductors”; cards – tasks for independent work in small groups; set of semiconductor devices NPP – 2; demonstration galvanometer; DC source (4V); demo switch; electric lamp 60-100W on a stand; electric soldering iron; connecting wires.
Lesson plan:
We must remember:
Yes, these are semiconductors. Just over half a century ago, they did not have any significant practical significance. In electrical engineering and radio engineering they used exclusively conductors and dielectrics. But the situation changed dramatically when, theoretically and then practically, the possibility of controlling the electrical conductivity of semiconductors was discovered.
What is the main difference between semiconductors and conductors and what features of their structure have made it possible to widely use semiconductor devices in almost all electronic devices, making it possible to significantly increase their reliability, greatly reduce their dimensions, and even create new ones that one could only dream of: creating miniature cell phones computers, etc.?
A large class of substances whose resistivity is greater than that of conductors, but less than that of dielectrics and decreases very sharply with increasing temperature.
These include elements of the periodic table: germanium, silicon, selenium, tellurium, indium, arsenic, phosphorus, boron, etc. some compounds: pig sulphide, cadmium sulphide, cuprous oxide, etc.
Demonstrations of the dependence of the electrical conductivity of semiconductors:
RT 10k FS – K1
It is necessary to emphasize that holes are not real particles. In both types of semiconductor conductivity, only valence electrons move. Conductivity differs from each other only in the mechanism of electron movement. Electronic conductivity is caused by the direction of movement of free electrons, and hole conductivity is caused by the movement of bound electrons moving from atom to atom, alternately replacing each other in bundles, which is equivalent to the movement of holes in the opposite direction.
Thus, in semiconductors there are two types of carriers - electrons and holes, the concentrations of which in pure semiconductors are the same - their own conductivity is small.
The conductivity of semiconductors depends significantly on the presence of impurities in their crystals:
Demonstration of impurities and n-type and p-type conductivity:
n – type p – type
Of particular interest is the flow of current not separately in n-type or p-type semiconductors, but through the contact of two semiconductors with different types of conductivity.
It is proposed to form groups of 4 students on a voluntary basis (this must be done before the start of the lesson to avoid chaotic movements around the room and loss of time).
Each group is given a task to complete. It contains questions, high-quality tasks of different levels, designed for both written and oral answers.
We listen to the answers of group representatives to the main questions of this topic, and correct possible errors. We collect written reports. We give grades for the work after studying the second part of the topic and completing repetition tasks, taking into account the KTU of each student in the group.
Homework: § 113; §114 of the textbook.
Labor training lesson plan.
Class 9
Section topic:
Electrical engineering and fundamentals of electronics. (3 hours)
Lesson topic No. 27: Semiconductor devices.
Target: Familiarize yourself with semiconductor devices.
During the classes:
1. Organizational part 3 min.
a) Greeting.
b) Identification of absentees.
c) Repetition of the material covered.
d) Announcing the topic of the lesson. Record the topic of the lesson in notebooks.
e) Communicating the objectives and lesson plan to students.
2.Repetition of the covered material -7 min.
What are the main types of electrical installation work?
What are conductive materials?
Application of conductor materials?
3. Studying new material 10 min.
Semiconductor devices are devices whose operation is based on the use of the properties of semiconductor materials
Semiconductor devices include :
-Integrated circuits (chips)
Semiconductor diodes (including varicaps, zener diodes, Schottky diodes),
Thyristors, photothyristors,
Transistors,
Charge-coupled devices
Semiconductor microwave devices (Gunn diodes, avalanche diodes),
Optoelectronic devices (photoresistors, photodiodes, solar cells, nuclear radiation detectors, LEDs, semiconductor lasers, electroluminescent emitters),
Thermistors, Hall sensors.
Main materials for the production of semiconductor devices are silicon (Si), silicon carbide (SiC), gallium and indium compounds.
Electrical conductivity
semiconductors depends on the presence of impurities and external energy influences (temperature, radiation, pressure, etc.). The flow of current is determined by two types of charge carriers - electrons and holes. Depending on the chemical composition, pure and impurity semiconductors are distinguished.
Semiconductors
4. Practical work 18 min.
One way to do this is to measure the resistance with an ohmmeter between the emitter and collector terminals when connecting the base to the collector and when connecting the base to the emitter. In this case, the collector power source is disconnected from the circuit. If the transistor is working properly, in the first case the ohmmeter will show low resistance, in the second - on the order of several hundred thousand or tens of thousands of ohms.
Semiconductor diode - a semiconductor device with one electrical junction and two terminals (electrodes). Unlike other types of diodes, the operating principle of a semiconductor diode is based on the pn junction phenomenon.
Semiconductor Diode Testing
When testing diodes using AMM, the lower measurement limits should be used. When checking a working diode, the resistance in the forward direction will be several hundred Ohms, and in the reverse direction - an infinitely large resistance. If the diode is faulty, the AMM will show a resistance close to 0 in both directions or a break if the diode breaks down. The resistance of transitions in the forward and reverse directions is different for germanium and silicon diodes.
5. Lesson summary 2 min.
6. Cleaning workplaces 5 min.
Topic: Semiconductors.
Purpose and objectives of the lesson:
· Educational: to form in the minds of students initial concepts about the electrical properties of semiconductors.
· Educational: continue to foster a culture of mental work, the development of personal qualities - perseverance, determination, creative activity, independence.
· Developmental: expand students’ scientific worldview to the phenomena they observe every day.
Equipment and visual aids:
Power supply, semiconductor diodes, light bulbs, connecting wires, demonstration stand, electrical measuring instrument - tester, information posters.
During the classes:
1. Organizational moment: (Task: creating a favorable psychological mood and activating attention).
2. Preparation for repetition and generalization of the material covered:
Graphic symbols of radioelements.
What is electric current?
Current strength, units of measurement.
The class is divided into teams and a competition is held to see who can draw the most symbols of radio elements and explain their purpose.
State the topic and purpose of the lesson.
Semiconductors. We must form initial concepts about the electrical properties of semiconductors.
Explanation of perspective.
Semiconductors in the form of various electronic devices are present in all aspects of our lives. Who can name specific applications of semiconductors?
(Possible answers: LED traffic lights, laser pointer, computers, televisions, cameras, television cameras, intercoms, washing machines, etc.)
We can say that the study and use of semiconductors has a significant impact on the content and quality of our lives. Let's consider in order what semiconductors are, what properties they have, what semiconductor devices have been created based on them, and what interesting experiments can be carried out with them.
3. Main stage.
New material
All substances found in nature are divided into three groups according to their electrical conductive properties:
Ш Conductors,
Ш insulators (dielectrics),
Ш semiconductors
frontal poll:
Question: “Why do metals conduct electric current well, but dielectrics practically do not?”
Answer: “conductors have a large number of free electrons, but dielectrics do not.
Question: “Are there no electrons in dielectrics?”
Answer: “There are no fewer electrons there than in metals, but they are bound to atoms and cannot move throughout the volume of the sample.”
Right.
The question of electrical conductivity of a material is a question of the presence of free, i.e., elements in it. electrical charges capable of moving. According to this indicator, semiconductors occupy an intermediate position between conductors and dielectrics.
Semiconductors include elements of group 4 of the periodic table, as well as some chemical compounds. A particularly convenient material to use is silicon (Si). The valence electrons of a semiconductor, like a dielectric, are connected to their atoms, but this connection is not as strong as in dielectrics. At room temperature, the thermal vibration energy is sufficient to cause some of the valence electrons to break away from their atoms and become free within the semiconductor sample. As a result, the semiconductor sample acquires the so-called electronic conductivity.
The departure of some valence electrons from their atoms gives rise to the second mechanism of electrical conductivity in semiconductors, which is called hole electrical conductivity. The fact is that the valence electron of a neighboring atom can move to the vacant place of the vacated electron. As a result, a vacancy, called a hole, can move throughout the volume of the sample and transfer electric charge. In fact, the movement and relay charge transfer are carried out by valence electrons, but the introduction of an imaginary particle with an elementary positive charge - a hole - turned out to be very convenient and has become firmly established in semiconductor physics.
Free electrons leaving their atoms create n-conductivity (n is the first letter of the Latin word negativus - negative). Holes create p - conductivity in a semiconductor (p is the first letter of the Latin word positivus - positive). - given for recording.
In a pure semiconductor, the number of free electrons and holes is the same.
By adding impurities, it is possible to obtain a semiconductor with predominantly electron or hole conductivity.
If we add 5-valence arsenic (antimony) to a 4-valence silicon crystal, we get an n - conductor.
By adding 3-valent indium, we get p - conductor.
A tiny amount of impurity is enough to change the concentration of free electrons or holes by several orders of magnitude. Therefore, free charge carriers formed due to impurities are called major, and the semiconductor's own free charge carriers are called minority.
Contact between electron and hole semiconductors (p-n junction).
If you simply bring two separate semiconductor samples with p and n conductivity into contact, then no current will flow through this connection. Semiconductor samples in air are covered with an oxide film, which is an excellent dielectric. The contact between electron and hole semiconductors is created within a single sample. To do this, for example, a semiconductor with hole electrical conductivity on one of the surfaces is doped with a donor impurity. As a result, the type of electrical conductivity at the surface becomes electronic, while hole conductivity remains in the depths. Consequently, a p-n junction appears, schematically shown in the figure.
The thermal movement of holes in the p-region and free electrons in the n-region will lead to their preferential movement from areas of high concentration to areas of lower concentrations. This process is called diffusion (under writing). As a result, holes from the p-region will rush to the n-region, and free electrons will flow from the n-region to the p. Those. A directed movement of charged particles occurs, which is an electric current. Since this current is due to diffusion, it is called diffusion current. In this case, the electrons transferred to the p-region turn out to be captured by atoms of the acceptor impurity, and the holes transferred to the n-region are nothing more than valence electrons of the donor impurity
The side of the p-region adjacent to the transition boundary is charged negatively, and the side of the n-region is charged positively. All these processes occur during the creation of the transition. As a result, the so-called transition occurs at the transition. contact potential difference, which acts against the diffusion current and reduces it to almost zero.
Electron-hole transition in an electrical circuit.
Let's perform the following experiment: Let's connect the electron-hole junction in series to a simple circuit, which consists of a source of constant EMF and a light bulb.
When the positive terminal of the EMF source is connected to the p-region, and the negative terminal through the light bulb is connected to n, a strong current flows in the circuit, which is indicated by the glow of the light bulb. When the transition is switched on in reverse polarity, there is no current in the circuit. This experiment suggests that the junction has one-way conductivity. Let us determine the mechanism of this effect.
In the first case, when the positive pole of the source is connected to the p-region, and the minus pole to the n-region, the voltage of the external source is opposite in polarity to the contact voltage. Consequently, the total voltage at the junction decreases in comparison with the equilibrium state. The opposition of this voltage to the diffusion current decreases, and this current increases greatly.
In the second case, the external voltage coincides in polarity with the contact voltage. In this case, the total voltage increases, which leads to a weakening of the diffusion current. Since this current has already been weakened almost to zero by the contact voltage, it remains practically zero.
Thus, the one-way conductivity of the p-n junction is due to the unidirectionality of the diffusion current through the junction. As for the drift current, it is always close to zero, since it is determined by very low concentrations of minority carriers in the p and n regions.
The polarity of the external voltage at the junction, at which it passes current, and the current itself in this case are called forward, the opposite polarity of the voltage and current are called reverse.
The one-way conductivity of the p-n junction is reflected in its symbols. In all cases, a contact is depicted and an arrow showing the direction of current flow - from the p-region to n (under the notation).
Fixing the material. Frontal survey.
1. What materials are classified as semiconductors?
2. Explain the mechanism of intrinsic electrical conductivity of semiconductors?
3. How does an impurity increase the electrical conductivity of a semiconductor.
4. Explain the mechanism of formation of electronic impurity electrical conductivity.
5. Explain the mechanism of formation of hole impurity electrical conductivity.
6. What is a p-n junction, how is it made,
7. Explain the one-way conductivity of a p-n junction.
Homework: review the material covered. Think about solving the following problem:
The chandelier has two light bulbs. Typically, to turn them on and off independently, three wires are used running from the switches to the chandelier. Is it possible, using the one-way electrical conductivity of p-n junctions, to get by with only two wires if you assemble the circuit shown in the figure.
(Answer: Yes you can, switch A controls light bulb a, switch B controls light bulb b)
Demonstration of changes in semiconductor resistance when illuminated
The installation is assembled with a photoresistor according to the drawing. Close the key and note the galvanometer reading (2-4 divisions). Turn on an electric lamp located at a distance of 0.5 m from the photoresistor, and slowly bring it closer to the photoresistor, monitoring the reading of the galvanometer. Draw students' attention that when illuminated, conductivity increases, which means resistance decreases.
