Electronics Workshop Training for Electronics and Communication Department

1. WELCOME To ELECTRONICS AND COMMUNICATION DEPARTMENT

2. WORKSHOP TRAINING JULY 2011 DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

3. Topics to be Covered • Section-I Introduction Electronics Components Semiconductor Physics Electronic devices Basic of Digital Electronics Electronics Instrumentation • Section-II Project Work

4. Introduction

5. Electronics:--- It is the word derived from electron which is present in all materials. The Branch of science and engineering which deals with the flow of electrons through vacuum or gas or semiconductor is known as electronics.

7. Applications of Electronics • Electronics is available in every sphere of life. • Electronics deals in the micro and millirange of voltage, current and power, and controls kilo, mega volts, amperes and watts. 1. Communications And entertainments 2.Industrial Applications 3.Defence Applications 4. Applications in Medical sciences 5.Applications in Auto mobiles 6.Digital Electronics 7.Instrumentation

8. Communications And entertainments Heinrich Hertz

10. Industrial Applications

11. Defence Applications

12. Applications in Medical sciences

13. Applications in Auto mobiles

14. Digital Electronics

15. Instrumentation

16. QUIZ • MSI means………………? • Birth of electronics took place in 1897 with the invention of ……………..? • The system of units adopted in INDIA is…………….? • The term giga stands for…………….? • The term eV stands for…………..? • The charge on an electron is………….coulomb? • The term micro stands for……………..? • The term pico stands for…………..? • The velocity of light is…………..m/s?

17. Any Questions??

18. Electronics Components

19. TYPES OF COMPONENTS • ACTIVE COMPONENTS The electronic components which are capable of amplifying or processing an electrical signal are called active component. Such as.. vacuum diodes, vacuum triodes, vacuum pentode, gas diodes, zener diodes, transistor, field effect transistor, unijunction transistors, silicon control rectifier, tunnel diode etc.

20. PASSIVE COMPONENTS Components which are not capable of amplifying or processing an electrical signal are called passive components such as resistor, capacitor and inductor.

21. Passive components • RESISTORS

22. Symbol Of Resistor (R) • It is used to limit the amount of current or divide the voltage in an electronic circuit. MATHEMATICAL - R = ( * L) / A REPRESENTATION

23. RESISTANCE • The ability of resistor to oppose the flow of current is called Resistance. • Unit of resistance R is ohm. ohm

24. Types of Resistors • There are two main Characteristics of resistance • Resistance in ohms • Power rating in watts FIXED RESISTORS • Carbon-composition Resistors: Made of mixture of carbon or graphite And clay. Two materials are mixed in the proportion for the desired value of R.

25. Carbon composition A broken resistor showing the ceramic core. A carbon resistor with and without the outer paint.

26. Carbon composition are readily available in values ranging from 1 ohm to 22 Mega ohm, having a tolerance range of 5 to 20 %. • FILM TYPE RESISTOR

27. Wire wound resistor • Nichrome, tungsten is used for wires. • Hollow porcelain cylinder • Ends are joined with metal pieces. • Assembly is coated with enamel containing powdered Glass.

28. Resistor colour coding

29. B • B • R • O • Y • G • B • V • G • W

30. Question • A resistor has a colour band sequence; red, black, red, gold • first digit----2 • second digit—0 • third multiplier----100 ohm • gold--------------5% • result----2000ohm or 2 k ohm with 5% tolerance

31. Question????

32. Variable Resistors • Some times it is require to change the value of resistance while in circuit such as voice controller, or speed controller, brightness controller etc. • This can be done with the held of variable resistor. These resistors can be carbon composition or wire wound. • Carbon composition Resistor • Wire wound variable Resistor

33. Carbon composition resistor • A thin carbon coating on pressed paper or a molded carbon disc constitutes the carbon composition resistance element. • Available from 1000 ohm to 5Mohm. • Power rating from1/2 to 2W.

34. Wire Wound variable Resistors Wire wound adjustable resistor Adjustable Contact Fixed contact

35. Wire is wound over a dough shaped core of Bakelite or ceramic. • The two ends of the resistance wire are joined to the external soldering plug terminals. 1 and 3. • The middle terminal is connected to the variable arm that contacts the resistor element.

36. Quiz • The electronic component which cannot process the signal are called ……………components. • The electronic component which can process the signal are called………………components. • The resistors are rated in………and……….. • When there are only three color bands on the resistor, the tolerance is………… • The third band on the resistor shows the……………. • 180ohm and 10% tolerance, the colour bands in the sequence will be…………………

37. ELECTRONICS INSTRUMENTS

38. CONTENTS • INTRODUCTION TO CRO • FUNCTION GENERATOR • DSO • MULTIMETER (DIGITAL AND ANALOG)

39. CRO • Cathode ray oscilloscope • It is used for the development of electronic circuits. • It shows the amplitude of electrical signals(power, current or voltage)as a function of time. • CRO is faster than other devices.

40. BLOCK DIAGRAM OF CRO

41. BLOCK DIAGRAM (i) Cathode ray tube (ii) vertical deflection system (iii) delay line (iv) horizontal deflection system (v) Trigger circuit (vi) Time base (vii) Power Supply

42. CRT

43. Electron gun produces an electron beam. • This beam is allowed to pass down the tube and to fall on the screen. • The screen is formed by the flat end of glass tube which is coated with the fluorescent material. • The point at which the electron beam strikes the screen, a spot is formed. • Beam passes through two plates i.e, vertical deflection plates and horizontal deflection plates.

44. Electron Gun Assembly • Consist of heater, focusing anodes and cathode.

46. FLOURESCENT SCREEN • The front end of CRT acts as a Fluorescent Screen. Inner side is coated with phosphor. • A phosphor converts the electrical energy to light energy. Phosphor crystals get excited and they emit light. This phenomenon is called fluorescence.

47. HORIZONTAL DEFLECTION SYSTEM • Time base generator • Trigger circuit • Horizontal amplifier

48. Time base generator • It generate saw tooth voltage, which will deflect the beam in the horizontal direction. • The CRT spot is deflected at a constant time dependant rate because of the voltage. TRIGGER CIRCUIT: • This circuit ensures that the horizontal sweep begins at the same point of the vertical input signal. • Without this there is no synchronization between sweep signal and the signal which is to be observed on the vertical deflection plates.

49. DELAY LINE • Every electronic circuit which are used in oscilloscope take certain time for the required operation. such as attenuators, amplifiers, waveshapers etc. • So Delay line is used to delay the signal for some time in the vertical sections. Generally, a time delay of 200 ns is provided to observe the leading edge of the waveforms. • the time delay at the horizontal deflecting plates the time delay is about 80ns. • Thus horizontal sweep starts prior to the vertical sweep.

50. FRONT PANEL CONTROL OF CRO • Basic general purpose controls • Controls in the Vertical Section • Controls in the Horizontal Section • Special Controls