SSGMCE, Shegaon Electronic Devices And Circuits

1. SSGMCE, ShegaonElectronic Devices And Circuits Lecture 01 Introduction & Importance of the Subject Prof. A. N. Dolas, Dept. of E&TC

2. Introduction • Why the name ‘electronics’? • I mean why not protonics or neutronics? Prof. A. N. Dolas, Dept. of E&TC

3. Introduction Contd. • What is electronics? • The IRE has defined electronics in proceedings of IRE vol.38(1950) as that: “ The Field of Science & Engineering, which deals with the study, design and use of devices, which depends on the conduction of electricity through a vacuum, gas or semiconductor”. Prof. A. N. Dolas, Dept. of E&TC

4. Beginning and Development of Electronics • 1850- German scientist Geissler • If the air is removed from a glass tube, it glows when an electric current passes through it. • 1878- British scientist, Sir William Crookes • The current in vacuum tubes seemed to consist of particles. Prof. A. N. Dolas, Dept. of E&TC

5. Beginning and Development of ElectronicsContd.. • 1897- Electron is discovered • French physicist, Perrin demonstrated that current in a vacuum tube consists of the movement of negatively charged particles in a given direction. Some of the properties of these particles were measured by British physicist Thomson. • These negatively charged particles were later on, named as electrons Prof. A. N. Dolas, Dept. of E&TC

6. Beginning and Development of ElectronicsContd.. • 1909- An American physicist • Measured the charge on an electron. • Result of these discoveries, the movement of electron could be controlled, and thus the electron era started. Prof. A. N. Dolas, Dept. of E&TC

7. Beginning and Development of ElectronicsContd.. • 1904-Fleming(Fleming Tube or diode vacuum tube) • Invented a vacuum tube that allowed electrical current only in one direction. • 1907- An American Scientist Lee deForest • Invented a tube, which could amplify weak electrical signals. Named as Triode vacuum tube. Prof. A. N. Dolas, Dept. of E&TC

8. Beginning and Development of ElectronicsContd.. • Around 1915- Triode vacuum tube used in oscillator circuit and telephone system. • 1916-Tetrode invented by a German engineer. • 1926- Pentode invented by a Dutch engineer. Prof. A. N. Dolas, Dept. of E&TC

9. Beginning and Development of ElectronicsContd.. • 1920- Invented first TV picture tube, called the Kinescope, by an American researcher. • Several types of microwave tubes were invented during world War II. Prof. A. N. Dolas, Dept. of E&TC

10. Beginning and Development of ElectronicsContd.. • 1947-Walter Britain, John Bardeen and William Shockley • Invented transistor at Bell laboratory (America). • Produced commercially in 1951. • 1959-Robert Noyce given an idea for making multiple devices on a single piece of silicon. Prof. A. N. Dolas, Dept. of E&TC

11. Functions • Rectification (DC Generation) • Amplification • Control • Generation (Oscillators) • Conversion of light into electricity • Conversion of electricity into light Prof. A. N. Dolas, Dept. of E&TC

12. Syllabus • Diode • Transistor • Transistorized circuits • Special purpose diodes • FET, UJT Prof. A. N. Dolas, Dept. of E&TC

13. Importance of Subject • Basic subject in Electronics engineering. • Subject plays vital role to understand electronics and communication. • Thorough understanding of this subject will provide the strong platform to the student for study of higher-level electronics. Prof. A. N. Dolas, Dept. of E&TC

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16. Basic Electronics Things to be covered: • What is electricity • Voltage, Current, Resistance • Ohm’s Law • Capacitors, Inductors • Semiconductors • Mechanical Components • Digital Electronics Prof. A. N. Dolas, Dept. of E&TC

17. What is Electricity • Everything is made of atoms • There are 118 elements, an atom is a single part of an element • Atom consists of electrons, protons, and neutrons Prof. A. N. Dolas, Dept. of E&TC

18. Electrons (- charge) are attracted to protons (+ charge), this holds the atom together • Some materials have strong attraction and refuse to loss electrons, these are called insulators (air, glass, rubber, most plastics) • Some materials have weak attractions and allow electrons to be lost, these are called conductors (copper, silver, gold, aluminum) • Electrons can bemade to move from one atom to another, this is called a current of electricity. Prof. A. N. Dolas, Dept. of E&TC

19. Surplus of electrons is called a negative charge (-). A shortage of electrons is called a positive charge (+). • A battery provides a surplus of electrons by chemical reaction. • By connecting a conductor from the positive terminal to negative terminal electrons will flow. Prof. A. N. Dolas, Dept. of E&TC

20. Voltage • A battery positive terminal (+) and a negative terminal (-). The difference in charge between each terminal is the potential energy the battery can provide. This is labeled in units of volts. Water Analogy Prof. A. N. Dolas, Dept. of E&TC

21. Voltage Sources: Prof. A. N. Dolas, Dept. of E&TC

22. Voltage is like differential pressure, • always measure between two points. • Measure voltage between two points • or across a component in a circuit. • When measuring DC voltage make • sure polarity of meter is correct, • positive (+) red, negative (-) black. Prof. A. N. Dolas, Dept. of E&TC

23. Ground Prof. A. N. Dolas, Dept. of E&TC

24. Exercise • Measure DC voltage from power supply using multimeter • Measure DC voltage from power supply using oscilloscope • Measure DC voltage from battery using multimeter • Measure AC voltage from wall outlet using a multimeter • Measure AC voltage from wall outlet using an oscilloscope Effective or Root Mean Square Voltage (Measured with multimeter) ERMS=0.707xEA E Prof. A. N. Dolas, Dept. of E&TC

25. Current • Uniform flow of electrons thru a circuit is called current. WILL USE CONVENTIONAL FLOW NOTATION ON ALL SCHEMATICS Prof. A. N. Dolas, Dept. of E&TC

26. To measure current, must break circuit and install meter in line. • Measurement is imperfect because of voltage drop created by meter. Prof. A. N. Dolas, Dept. of E&TC

27. Resistance • All materials have a resistance that is dependent on cross-sectional area, material type and temperature. • A resistor dissipates power in the form of heat Prof. A. N. Dolas, Dept. of E&TC

28. Various resistors types Prof. A. N. Dolas, Dept. of E&TC

29. When measuring resistance, remove component from the circuit. Prof. A. N. Dolas, Dept. of E&TC

30. Resistor Color Code Prof. A. N. Dolas, Dept. of E&TC

31. Exercise • Determine the resistance of various resistors of unknown value using the resistor color code • Using the multimeter, compare the specified resistance and measured resistance • Using the multimeter to examine the characteristics of various potentiometers Prof. A. N. Dolas, Dept. of E&TC

32. Ohm’s Law Prof. A. N. Dolas, Dept. of E&TC

33. Prototyping Board Example of how components are Inserted in the protoboard Prof. A. N. Dolas, Dept. of E&TC

34. Exercise • Calculate the total current and voltage drop across each resistor shown in Figure 1 • Build the circuit in Figure 1 on the prototype board • Measure the total circuit current and voltage drops across each resistor and compare • the calculated and measured values Prof. A. N. Dolas, Dept. of E&TC

35. Capacitance A capacitor is used to store charge for a short amount of time Capacitor Battery Unit = Farad Pico Farad - pF = 10-12F Micro Farad - uF = 10-6F Prof. A. N. Dolas, Dept. of E&TC

36. Prof. A. N. Dolas, Dept. of E&TC

37. Capacitor Charging Prof. A. N. Dolas, Dept. of E&TC

38. Capacitor Discharge Prof. A. N. Dolas, Dept. of E&TC

39. Inductance Prof. A. N. Dolas, Dept. of E&TC

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41. Discussion!! Prof. A. N. Dolas, Dept. of E&TC

42. SSGMCE, ShegaonElectronic Devices And Circuits Lecture 02 Atomic Structure Prof. A. N. Dolas, Dept. of E&TC

43. Electrons in Isolated Atoms • Isolated atoms have energy levels • The electrons can only be found in these energy states Prof. A. N. Dolas, Dept. of E&TC

44. Atoms in Solids • Atoms form a lattice structure The lattice affects the structure of the energy levels of each atom – we now have joint levels for the entire structure Prof. A. N. Dolas, Dept. of E&TC

45. Intrinsic Semiconductor • Elemental or pure semiconductors have equal numbers of holes and electrons • Depends on temperature, type, and size. • Compound Semiconductors can be formed from two (or more) elements (e.g., GaAs) Prof. A. N. Dolas, Dept. of E&TC

46. Extrinsic Semiconductors • A pure semiconductors where a small amount of another element is added to replace atoms in the lattice (doping). • The aim is to produce an excess of either electrons (n-type) or holes (p-type) • Typical doping concentrations are one part in ten million • Doping must be uniform throughout the lattice so that charges do not accumulate Prof. A. N. Dolas, Dept. of E&TC

47. N-Type and P-Type • One valence electron too many (n-type) • Arsenic, antimony, bismuth, phosphorus • One valence electron too few (p-type) • Aluminum, indium, gallium, boron Prof. A. N. Dolas, Dept. of E&TC

48. What Are Diodes Made Out Of? Si +4 Si +4 Si +4 Si +4 Si +4 Si +4 Si +4 Si +4 Si +4 • Silicon (Si) and Germanium (Ge) are the two most common single elements that are used to make Diodes. A compound that is commonly used is Gallium Arsenide (GaAs), especially in the case of LEDs because of it’s large bandgap. • Silicon and Germanium are both group 4 elements, meaning they have 4 valence electrons. Their structure allows them to grow in a shape called the diamond lattice. • Gallium is a group 3 element while Arsenide is a group 5 element. When put together as a compound, GaAs creates a zincblend lattice structure. • In both the diamond lattice and zincblend lattice, each atom shares its valence electrons with its four closest neighbors. This sharing of electrons is what ultimately allows diodes to be build. When dopants from groups 3 or 5 (in most cases) are added to Si, Ge or GaAs it changes the properties of the material so we are able to make the P- and N-type materials that become the diode. The diagram above shows the 2D structure of the Si crystal. The light green lines represent the electronic bonds made when the valence electrons are shared. Each Si atom shares one electron with each of its four closest neighbors so that its valence band will have a full 8 electrons. Prof. A. N. Dolas, Dept. of E&TC

49. N-Type Material N-Type Material: When extra valence electrons are introduced into a material such as silicon an n-type material is produced. The extra valence electrons are introduced by putting impurities or dopants into the silicon. The dopants used to create an n-type material are Group V elements. The most commonly used dopants from Group V are arsenic, antimony and phosphorus. The 2D diagram to the left shows the extra electron that will be present when a Group V dopant is introduced to a material such as silicon. This extra electron is very mobile. +4 +4 +4 +4 +5 +4 +4 +4 +4 Prof. A. N. Dolas, Dept. of E&TC

50. P-Type Material P-Type Material: P-type material is produced when the dopant that is introduced is from Group III. Group III elements have only 3 valence electrons and therefore there is an electron missing. This creates a hole (h+), or a positive charge that can move around in the material. Commonly used Group III dopants are aluminum, boron, and gallium. The 2D diagram to the left shows the hole that will be present when a Group III dopant is introduced to a material such as silicon. This hole is quite mobile in the same way the extra electron is mobile in a n-type material. +4 +4 +4 +4 +3 +4 +4 +4 +4 Prof. A. N. Dolas, Dept. of E&TC