To ELECTRONICS AND COMMUNICATION DEPARTMENT

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WELCOME

• To ELECTRONICS AND COMMUNICATION DEPARTMENT

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WORKSHOP TRAINING

• JULY 2011
• DEPARTMENT OF ELECTRONICS AND COMMUNICATION
  ENGINEERING

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Topics to be Covered

• Section-I
• Introduction
• Electronics Components
• Semiconductor Physics
• Electronic devices
• Basic of Digital Electronics
• Electronics Instrumentation
• Section-II
• Project Work

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Introduction
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• 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.

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Applications of Electronics

• Electronics is available in every sphere of life.
• Electronics deals in the micro and milli range 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

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Communications And entertainments

Heinrich Hertz
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Industrial Applications
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Defence Applications
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Applications in Medical sciences
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Applications in Auto mobiles
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Digital Electronics
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Instrumentation
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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?

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Any Questions??
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Electronics Components
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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.

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

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Passive components

• RESISTORS

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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

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RESISTANCE

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

ohm
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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.

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Carbon composition

• A
  
  
  broken resistor showing the ceramic
  core.

A carbon resistor with and without the outer
paint.
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• 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

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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.

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Resistor colour coding
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• B
• B
• R
• O
• Y
• G
• B
• V
• G
• W

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Question

• A resistor has a colour band sequence red,
  black, red, gold
• first digit----2
• second digit0
• third
  multiplier----100 ohm
• 
  gold--------------5
• 
  result----2000ohm or 2 k ohm with 5
• tolerance

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Question????
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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

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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.

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

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Quiz

• The electronic component which cannot process the
  signal are called components.
• The electronic component which can process the
  signal are calledcomponents.
• The resistors are rated inand..
• 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

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ELECTRONICS INSTRUMENTS
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CONTENTS

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

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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.

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BLOCK DIAGRAM OF CRO
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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

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CRT
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• 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.

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

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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.

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HORIZONTAL DEFLECTION SYSTEM

• Time base generator
• Trigger circuit
• Horizontal amplifier

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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.

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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.

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FRONT PANEL CONTROL OF CRO

• Basic general purpose controls
• Controls in the Vertical Section
• Controls in the Horizontal Section
• Special Controls

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Display

• A is the display. This can be a phosphor screen
  or an LCD, and is usually about 100mm corner to
  corner.
• B shows the trace. This is the line drawn by the
  scope to represent the signal. On a CRO, this
  line is created by a bright dot moving across the
  screen at high speed (sometimes faster than the
  speed of light - because nothing
  is physically moving across the screen, this does
  not break any rules). On a digital scope, the
  line is drawn on the LCD like a graphical
  calculator.
• The screen is overlaid with a grid of horizontal
  (C) and vertical (D) lines, called the graticule,
  which divides the screen into squares,
  called major divisions. The graticule is usually
  10 major divisions wide and 8 tall.
• The central horizontal and vertical lines (E) are
  usually thicker than the others and are divided
  into minor divisions, usually five per major
  division. When we talk about "divisions" in later
  sections, we will always mean the major divisions
  - the minor divisions are just to aid measuring.
• There are also special horizontal lines labeled
  "0" (2.5 divisions below the centre) and "100"
  (2.5 divisions above it). The "10" and "90" lines
  have tick marks like the central axes. These four
  horizontal lines are guides for scaling the
  signal for rise-time measurement.

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Power, Calibration and Display Controls

• 1 is the Power On/Off Button. 2 is the Power
  Indicator which lights when the oscilloscope is
  on. This may be an LED in newer scopes or a neon
  tube in older scopes.
• 3 is the trace rotation (TR) control. This sets
  the inclination of a flat signal relative to the
  graticule. This is usually a Trimpot and needs to
  be set using a flat-bladed screwdriver. Once set,
  this control should retain its position and will
  rarely need adjusting.
• 4 is the intensity of the trace. Turning this up
  increases the brightness of the trace, and
  turning it down makes it dimmer. An overly bright
  trace can damage the phosphor of the screen if
  the dot is moving too slowly.
• The trace can get fuzzy if the electron beam is
  not focused correctly. The focus control (5) sets
  this. Most scopes can focus the beam to form a
  trace about 1mm wide.
• 6 is the calibration point. This gives a steady
  square wave at a set frequency and voltage,
  allowing the scaling of the trace to be set
  accurately. Sometimes, more than one frequency
  and voltage is available to give a more
  representative calibration. The standard
  calibration signal is between 0V and 2V at 1KHz.

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Vertical Axis Controls

• When plotting a signal against time (the standard
  use for a scope), the vertical axis represents
  voltage. Most controls for the vertical axis are
  duplicated for each channel to give independent
  control over each signal.
• 7 controls the position of the trace. It can be
  adjusted to set the voltage relative to a ground,
  or it can be adjusted to separate the two signals
  - perhaps the first channel in the top half of
  the screen and the second channel in the bottom.
• 8 inverts the relevant channel. That is, the
  negative voltage is displayed, and the trace is
  upside-down.
• 9 is the vertical scale control, often called the
  volts/div. control. This sets the height of the
  trace. It operates in discrete steps.
• 10 is a variable height control. It can adjust
  the height of the trace up to the next set
  increment on the volts/div. control. When set to
  CAL, the height is as stated on the volts/div.
  control.
• 11 is the AC/DC toggle. When set to AC, any DC
  component of the voltage is filtered out by
  switching a capacitor in series with the input
  signal, leaving just an AC voltage. This is
  useful when the DC component swamps the AC
  component, making it either too small to see or
  driving it off the top of the screen. When set to
  DC, the signal is displayed as is.

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• 12 is the GND toggle. By selecting this, the
  input signal is ignored, and the trace shows 0V.
  This can be useful to measure a voltage or to
  eliminate one of the traces from the display.
• 13 is the Channel 1 signal input and 14 is the
  Channel 2 input. This is where the oscilloscope's
  probe is plugged in.
• Each channel has a copy of most of these controls
  (except chop/alt, which applies to all channels).
  The way the channels are combined is set
  using 15, which is usually a sliding switch. When
  set to CH. 1, only the trace from Channel 1 is
  displayed, and likewise for CH. 2. When DUAL is
  selected, the traces are shown side by side. This
  is when the chop/alt control applies. ADD shows
  the sum of the two traces as one trace. By
  inverting the traces, one can be subtracted from
  the other. This can be seen in the illustration
  below. This shows a square wave on one channel
  and a sinusoidal wave on the other. On the left,
  the scope is set to "dual", and the two traces
  are shown side by side. On the right, the scope
  is set to "add", and the trace is the sum of the
  two signals.

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Horizontal Axis Controls

• When operating in the normal voltage vs. time
  mode, this axis represents time. The primary
  control is the time base selector, 19. The time
  base is the length of time displayed per major
  horizontal division on the screen. This ranges
  from about 0.1 milliseconds to about 1 second (or
  more on digital scopes).
• The position of the trace from side to side is
  controlled by 17. This is useful if part of the
  trace is off the edge of the screen but you don't
  want to change the time base.
• The 10 MAG control, 16, is a very useful control
  if you want to quickly zoom in on a feature
  without changing the timebase and losing your
  settings. This buttom magnifies the central area
  of the trace by a factor of 10 in the horizontal
  direction (but leaves the voltage height
  unchanged).
• 18 toogles the mode between the usual voltage vs.
  time format and the XY mode. This continuously
  plots the voltage on Channel 1 along the
  horizontal axis against the voltage on Channel 2
  (the vertical axis). This can be extremely useful
  to analyse frequency or phase relationships. This
  is a complex topic, and will be covered in its
  own section later in the module.
• 20 and 21 act in much the same way as 10 does on
  the vertical axis. This diagram shows it to be
  slighly different from the vertical control. To
  select a non-standard timebase, press 20, and
  adjust 20 until the correct setting is obtained.
  To return to a calibrated time base, press 20
  again. Sometimes these controls are the same
  style as 10, sometimes the vertical controls are
  like these.

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• 22 is the GND terminal of the scope. This is used
  to set a "datum" voltage against which to measure
  the voltages on the input channels. Be careful
  when using isolated mains voltage circuits, as
  the "ground" is sometines floating at mains
  voltage, and can short to the real ground,
  casuing injury or death.
• 23 toggles between chop-mode and alt-mode.
  Chop-mode means that when the scope is drawing
  two signals side by side it alternates rapidly
  between the two over the course of passing across
  the screen. This action is called chopping.
  Alt-mode alternates at the end of each pass, and
  can appear to flicker at slow speeds.

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FUNCTION GENERATOR
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• Function generator is an instrument which
  produces different functions (waveforms)at the
  output.
• A function generator can be capable of generating
  Sine, square and triangular functions
  simultaneously at the output.
• Range of frequencies is from few Hz to several
  MHz.
• Amplitude range is from mv to few tens of volts
  rms.

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Block Diagram of Function generator
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Working

• Frequency control can be internal or external.
• If external then DC voltage is applied.
• Upper and lower current sources supply constant
  DC currents I1 and I2 opposite in directions.
• Let upper supply is ON and supplying dc constant
  current I1
• to an integrator. Now the output of an
  integrator is
• Voi1/c?I1 dt
• Voi is the linear ramp wave increasing towards
  positive as shown in fig.

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• Ramp voltage is less than upper triggering
  point(UTP).

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Features of Function Generator

• Freq range- 0.01Hz to 100 KHz
• It can produce different waveforms like sine,
  square, triangular, sawtooth etc.
• Accuracy is within (-1)
• Distortion is less than 1 for sine wave.

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DSO (Digital storage oscilloscope)
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