EP LAB -GRP - B Electronics

8/11/2019 EP LAB -GRP - B Electronics

1/28

STUDY OF ELECTRONIC COMPONENTS AND EQUIPMENTS

AIM:

To study the basic principle and working of Electronic Components and

equipments.

THEORY:

DEFINITION OF RESISTOR:

Resistor is a device that will convert electric energy (via electric current) into heat

energy. nlike a capacitor! then! a resistor does "#T store energy. Resistor is a device

which opposes the flow of current. $t consumes it at a rate of

(%)

where the $&' relation for a resistor (known as #hms *aw.+)

(,)

has been used. -retty much all materials have resistance! which is given by

()

/here

is the length of the resistor is! is the cross&sectional 0rea of the resistor! and is the

resistivity of the resistor material. 1ifferent materials have different resistivities.

TYPES OF RESISTOR:

%

E2p."o31ate 3


2/28

There are two types of ad4ustable resistors3 the potentiometer (usually called a pot+) and

a rheostat. sually a potentiometer is smaller and ad4ustable with a small screwdriver.

Rheostats are much larger and are capable of using large currents.

RESISTOR COLOUR CODING:

Typically! a resistor will have 5 colour bands on them which represent the resistance

values of the resistor. Each colour of the Resistor Colour Code+ represents a numeric

value3

"umeric Representation Colour

6 7lack

% 7rown

, Red

#range

5 8ellow

9 :reen

; 7lue

< 'iolet

= :ray

> /hite

&% :old (rd band)

9? :old (5th band)

%6? @ilver (5th band)

,6? "o Colour (5th band)

,


3/28

The resistance is determined by the first three colors on the resistor via the formula

(5)

Thus! a resistor with the first three colours of

red & white & blue

would have a resistance of ! or ,> . Aor resistance values of less than %6

! a gold third band is used. Thus!

brown & red & gold

would represent ! or %., .


4/28

Resistor values can vary greatly! and so the 5th colour band represents the tolerance for

the resistor. $f there is no 5th band! then one can only be assured that the resistance value

is within ,6? of the value represented by the first colour bands.

Two resistors in parallel! and ! have a net resistance of the product over the sum of

the resistances

(9)

Two resistors in series! and ! have a net resistance of the sum of the resistances

STUDY OF CATHODE RAY OSCILLOSCOPE:

0 cathode ray oscilloscope! CR# or scope! is a versatile electronic instrument

used in many fields of basic and applied research to measure time&dependent voltage

signals. 0 CR# consists of a cathode ray tube! CRT (similar to a television picture tube)!

and associated circuits. 7ecause an oscilloscope has very high resistance inputs (like a

voltmeter)! it draws very little current and thus usually does not disturb the circuit being

studied. The oscilloscope is an essential part of several e2periments in our introductory

physics courses. #ur scopes are not simplified for teaching but are versatile models

suitable for use in research physics! engineering and medical laboratories.

5


5/28

B. Components:

Aigure % shows the basic components of the cathode ray tube. The principal parts

of the tube are3

Fi!"e #: Components o$ % &%t'o(e "%) t!*e.

%. AilamentBheats the cathode with a current of a few amperes.

,. CathodeBa metal surface coated with a metallic o2ide which emits electrons when

it is heated emission currents of a few m0 are typical.

. Control :ridBcontrols the electron current and consequently the brightness of the

image. The potential applied to it can be varied by ad4usting the $"TE"@$T8

control. 7y the time the electron beam reaches the screen! it is reduced to a few

D0 1o not make the spot brighter than necessary as this may damage the screen.

9


6/28

$f the spot has a halo around it! turn down the intensity the intensity required for

a spot is less than that required for a line.

5. Aocusing 0nodeBpermits sharpening the image. Aocus is controlled by the

A#C@ knob.

9. 0cceleration 0nodeBaccelerates the electrons toward the screen so that they strike

it with enough energy! several k'! to give off light. There is no e2ternal control to

ad4ust this voltage.

;. 'ertical 1eflection -latesBtwo horiontal plates parallel to the beam. The beam

can be deflected by a potential difference between these plates! usually derived

from the amplified signal being studied.

The 'ERT$C0* -#@$T$#" control applies a 1C voltage to offset or center the

beam vertically.


7/28

7efore it hits the screen! the beam is deflected by the electric fields on the plates (;!


8/28

Refer to the picture. The function of each switch! if itLs not obvious! has been described

earlier or is described below.

%. -ower switch

,. -ower lamp

. Aocus control

5. Trace rotation control & although the CRT is magnetically shielded! it is still possible

for magnetic fields to distort the beam. This control lets you level the trace.

9. $ntensity control

;. Channel % $nput ($n M&8 mode! this becomes the M&a2is input.) These are 7"C&type

connectors! which are a type Aigure , @awtooth @weep 'oltage of coa2ial connector. The

signal is at the center pin while the outer metal casing is a ground (for this scope).

. $nput coupling switches (0C&:"11C) 0C blocks any 1C component! using a

capacitor! so that only changes in the signal may be seen. :"1 shorts out the input tohelp you determine where the trace is with ero input. 1C shows you everything.

%6! %%. 'oltsH1iv selector

%,! %. '0R (-** 29 :0$") Aine ad4ustment of vertical input gain.

%5. -osition control

%9. -#@$T$#" (-** $"'ERT) $nverts the trace of Channel % when pulled out.

=


9/28

%;. Gode select switch & CF%! CF,! 0*T! CF#-! 011. This switch selects which signal

you can view on the CRT. 0*T and CF#- let you see both. 0*T completes one sweep of

channel % and then one sweep of channel ,! etc. CF#- moves quickly back and forth

between the two channels many times on each sweep. This happens too fast to see and is

better when viewing slow signals that donLt complete a sweep in less than %66 msec.

011 is generally used with $"'ERT to see the difference between two signals.

%. @weep 'ariable control

,6. -#@$T$#" (-** 2%6 G0:)

,%. Trigger @#RCE select switch. This determines what is used for triggering the scope.

$f @#RCE is set on $"T! it triggers with a change in the vertical input voltage. $f it is set

on *$"E! it triggers with the 0C line frequency (;6 hert). The EMT setting is for an

e2ternal trigger signal. 8ou will generally use an internal trigger! derived from the signal

itself.

,,. $nternal Trigger. @elects the internal triggering signal source! channel %! etc.

,. E2ternal Trigger (or M&$" connector $nput for e2ternal trigger).

,5. *evel Control @ets the voltage level at which the sweep starts or triggers. /hen it is

set to N! the Lscope triggers on the rising edge (positive slope) of the waveform when set

to &! it triggers on the falling edge.

,9. Trigger Gode select switch. 8ou will generally use 0T#! which lets the scope free&

run if it is not triggered. #n G0"0*! the scope will 4ust go blank if itJs not triggered.

Aigure 3 CR# controls

,;. Calibrate 6.9' (O% kF at 6.9'.)

,


10/28

Aollow these instructions to measure the period and amplitude of a periodic

signal. ("umbers in parenthesis refer to the controls in Aig. .)

a. -lug in the scope and turn on the power (%).

b. Connect the input signal to the Channel % input (;).

c. @et the trigger @#RCE (,%) selection switch to $"T (for internal triggering).

d. @et G#1E(,9) to 0T#.

e. @et the $"T TR$:(,,) selection switch to CF%.

f. 0d4ust the level control to obtain a stable image.

F.#. Me%s!"in % Pe"io(:

0d4ust the TimeH1iv switch until you see a sequence of a few oscillations on the

screen. Gake sure the @weep 'ariable control (%>) is locked (inner knob fully clockwise).

#therwise! any measurements will be meaningless. Geasure as large an image as possible

to obtain the highest precision in your time measurements. $f there are 5 full periods on

the screen! measure the time for the 5 periods and divide by 5. 0lternately! ad4ust the

T$GEH1$' (%=) so that only %&, periods appear on the screen.

F.. /o+t%e Me%s!"ement:

0d4ust the 'oltsH1iv switch so that your waveform nearly fills the screen

vertically. Gake sure the 'ar :ain (%,!%) is locked. Geasure the amplitude of the signal

in screen divisions and multiply by the setting of the 'oltsH1iv switch to obtain the signal

amplitude in volts.

F.0. Liss%1o!s Fi!"es %n( D!%+ T"%&e:

The oscilloscope is often used to compare the time dependence and amplitudes of

two signals. Aor this purpose the Iscope has two input connectors and circuits and can

display two signals at the same time with a common time a2is and a trigger derived from

either source. 0n alternative way to compare two signals is to plot one signal on the

horiontal a2is (2) and the other on the on the vertical a2is (y). This will produce a

*issa4ous figure on the screen. Connect one signal to the 2a2is (CF%) and the other to the

%6


11/28

y&a2is (CF,). @elect M8 mode using the T$GEH1$' knob (%=). 0d4ust the input

sensitivities until the signal nearly fills the screen.

RESULT:

Thus the basic principle and working of Electronic Components and

Equipments were studied.

%%

E2p."o3

1ate 3


12/28

STUDY OF LOGIC GATES

AIM:

To test of $Cs by using verification of truth table of basic $Cs.

APPARATUS REQUIRED:

S. No App%"%t!s R%ne Q!%ntit)% 1igital trainer kit & %

, 0"1 :ate $C


13/28

. OR %te 2IC 3407:

The operation of #R gate is such that the output is F$:F when any of the inputs

are F$:F. /hen all of the inputs are *#/! the output is *#/. The basic purpose of #R

gate is to determine whether one or more input bit(s) are F$:F.

#R function! KJ0N7

@ymbol Truth Table -in 1iagram

0. NOT %te 2IC 34547:

%

Input Outpu

t

A B Z=A.B

0

0

1

1

0

1

0

1

0

0

0

1

0"1 :ate

0

7

K

$nput #utput

0 7 KJ0N7

6

6

%

%

6

%

6

%

6

%

%

%

#R gate7

K0

%

,

5

9

;

6 %6 ,%>V

9 ;9 ,


19/28

SOLDERING TECHNIQUE:

$t depends on

%. "ature and type of 4oint

,. Gelting temperature of solder

. @oldering flu2 used.

@oldering Equipment3

The equipments used for soldering are blowlamps! soldering iron! soldering pot!

laddle etc.!

7low lamp3

sing blowlamp an open flame is obtained by burning kerosene! petrol or spirit.

@oldering $ron3

"owadays electric soldering iron is used in various types of soldering 4obs. Feat is

obtained from a nichrome wire element in the range of %6/ to ,/ or bigger and is used

to heat soldering bit. The key to the function of iron is in the bit itself. The bit of the

soldering iron has to perform following functions.

%. $t stores heat and convey it from heat source to work.

,. Conveys molten solder and often flu2 to work. Fowever it is not recommended. $t is

better to apply solder to work piece correctly.

. $t can be used to remove surplus solder from the 4oints.

5. @oldering bits are made of copper.

1rilling3

1rilling of holes into -C7 to mount components is an important machinery

operation. Aor drilling holes the drills bit diameter is chosen as 6.69 mm higher then the

hole diameter. 1rilling machines for -C7 applications are available in a wide range of

designs. The speeds mostly used are around ,6666&96666 rpm.

%>


20/28


21/28

>. Cut the pro4ected part of components after soldering.

Desoldering:

%. -lace the tip of the soldering iron on the 4oints until the solder is melt.

,. sing the desoldering pump (or) desoldering wik remove the molten state

. #n the component side using tweeter remove the desolderedcomponents.

RESULT:

The given components are soldered onto the -C7 and their working is tested.

,%


22/28


23/28

-ercentage Regulation J

"* A*

A*

(' & ' )%66?

'"

/ith filter!

pp

dcr

' %' J

RC ,"

# .

pp

rms

r

r

'' J

, .

Ripple Aactor

rmsr

dc

' %

' 5 #$%= =

CIRCUIT DIAGRAM:

H%+$;-%>e Re&ti$ie" -it'o!t $i+te":

H%+$;-%>e Re&ti$ie" -it' $i+te":

F!++;-%>e Re&ti$ie" -it'o!t $i+te":

,


24/28

Aull&wave Rectifier3

/ithout filter!

0verage 'oltage dc m' J ,' H

.

RG@ 'oltage rms m' J ' H ,

.

Ripple Aactor

,

ac

dc

'J J %

'

rms

d

!

!

.

-ercentage Regulation J

/ith filter!

"* A*

A*

(' & ' )%66?

'"

pp

dcr

' %' J

RC ,"

# .

pp

rms

r

r

'' J

, .

Ripple Aactor

rmsr

dc

' %

' 5 #$%= =

PROCEDURE:

/ithout capacitor filter3

,5


25/28


26/28

P%"%mete"s H%+$;-%>e "e&ti$ie" Full-wave rectifier

Ripple factor3

/ithout filter

/ith filter

Theoretical -ractical Theoretical Pratial

MODEL GRAPH:

H%+$ e 2


27/28

F!++ e:

/ith capacitor filter3

,


28/28

Documents

EP LAB -GRP - B Electronics