Date: __/__/____

Experiment 1

FAMILIARISATION OF COMPONENTS AND EQUIPMENTS

AIM:

To study the operation of the following electronic components and equipments.

1. Resistors 2. Capacitors 3. Inductors 4. CRO 5. Function Generator 6. Power Supplies 7. Breadboard

COMPONENTS AND EQUIPMENTS REQUIRED

Resistors, Capacitors, Inductors, CRO, Function Generator, Power Supplies,

Breadboard

INTRODUCTION

1. RESISTOR

A Resistor is a passive two-terminal electrical component that implements electrical

resistance as a circuit element. The current through a resistor is in direct proportion to the

voltage across the resistor's terminals. This relationship is represented by Ohm's law:

V = I/R

Where I is the current through the conductor in units of amperes, V is the potential

difference measured across the conductor in units of volts, and R is the resistance of the

conductor in units of ohms. The ratio of the voltage applied across a resistor's terminals to the

intensity of current in the circuit is called its resistance, and this can be assumed to be a

constant (independent of the voltage) for ordinary resistors working within their ratings.

1.1. COLOUR CODING OF RESISTOR

Colour Codes are used to identify the value of resistor. The numbers to the Colour are

identified in the following sequence which is remembered as BBROY GREAT BRITAN

VERY GOOD WIFE (BBROYGBVGW) and their assignment is listed in following table.

Black Brown Red Orange Yellow Green Blue Violet Grey White

0 1 2 3 4 5 6 7 8 9

Table 1: Colour codes of resistor

Figure 1 : Procedure to find the value of Resistor using Colour codes

1.2. RESISTOR COLOUR CODES:

Resistors are devices that limit current flow and provide a voltage drop in electrical

circuits. Because carbon resistors are physically small, they are color-coded to identify their

resistance value in Ohms. The use of colour bands on the body of a resistor is the most

common system for indicating the value of a resistor. Color-coding is standardized by the

Electronic Industries Association (EIA).

Use the Resistor Colour Code Chart to understand how to use the colour code

system. When looking at the chart, note the illustration of three round resistors with

numerous colour code bands. The first resistor in the chart (with 4 bands) tells you the

minimum information you can learn from a resistor. The next (a 5-band code) provides a

little more information about the resistor. The third resistor (a 6-band) provides even more

information. Each colour band is associated with a numerical value.

How to read a typical 4-band, 5-band and 6-band resistor:

4-Band:

Reading the resistor from left to right, the first two colour bands represent significant

digits, the third band represents the decimal multiplier, and the fourth band represents the

tolerance.

5-Band:

The first three colour bands represent significant digits, the fourth band represents the

decimal multiplier, and the fifth band represents the tolerance.

6-Band:

The first three colour bands represent significant digits, the fourth band represents the

decimal multiplier, the fifth band represents the tolerance, and the sixth band represents the

temperature coefficient.

1.3. DEFINITIONS OF COLOUR BANDS:

The colour of the multiplier band represents multiples of 10, or the placement of the

decimal point. For example: ORANGE (3) represents 10 to the third power or 1,000. The

tolerance indicates, in a percentage, how much a resistor can vary above or below its value.

A gold band stands for 5%, a silver band stands for 10%, and if there is no fourth band it

is assumed to be 20%. For example: A 100-Ohm 5% resistor can vary from 95 to 105

Ohms and still be considered within the manufactured tolerance. The temperature coefficient

band specifies the maximum change in resistance with change in temperature, measured in

parts per million per degree Centigrade (ppm/C).

Example (from chart):

Lets look at the first resistor on the chart. In this case, the first colour band is BROWN. Following the line down the chart you can see that BROWN represents the number

1. This becomes our first significant digit. Next, look at the second band and you will see it is

BLACK. Once again, follow the line down to the bar scale; it holds a value of 0, our second

significant digit. Next, look at the third band, the multiplier, and you will see it is ORANGE.

Once again, follow the line down to the bar scale; it holds a value of 3. This represents 3

multiples of 10 or 1000. With this information, the resistance is determined by taking the first

two digits, 1 and 0 (10) and multiplying by 1,000. Example: 10 x 1000 = 10,000 or 10,000

Ohms. Using the chart, the fourth band (GOLD), indicates that this resistor has a tolerance of

5%. Thus, the permissible range is: 10,000 x .05 = 500 Ohms, i.e. 9,500 to 10,500 Ohms.

1.4. TYPES OF RESISTORS

A. Carbon Resistors B. Wire wound Resistors

Carbon Resistors

There are many types of resistors, both fixed and variable. The most common type for

electronics use is the carbon resistor. They are made in different physical sizes with power

dissipation limits commonly from 1 Watt down to 1/8 Watt. The resistance value and

tolerance can be determined from the standard resistor colour code.

A variation on the colour code is used for precision resistors which may have five

coloured bands. In that case the first three bands indicate the first three digits of the

resistance value and the fourth band indicates the number of zeros. In the five band code the

fifth band is gold for 1% resistors and silver for 2%.

Figure 2 : Carbon Resistor

Wire Wound Resistors

Wire wound resistors are commonly made by winding a metal wire, usually

Nichrome, around a ceramic, plastic, or fiberglass core. The ends of the wire are soldered or

welded to two caps or rings, attached to the ends of the core. The assembly is protected with

a layer of paint, moulded plastic, or an enamel coating baked at high temperature. Because of

the very high surface temperature these resistors can withstand temperatures of up to +450

C. Wire leads in low power wire wound resistors are usually between 0.6 and 0.8 mm in

diameter and tinned for ease of soldering.

For higher power wire wound resistors, either a ceramic outer case or an Aluminium

outer case on top of an insulating layer is used. The aluminium-cased types are designed to

be attached to a heat sink to dissipate the heat; the rated power is dependent on being used

with a suitable heat sink, e.g., a 50 W power rated resistor will overheat at a fraction of the

power dissipation if not used with a heat sink. Large wire wound resistors may be rated for

1,000 watts or more.

Because wire wound resistors are coils they have more undesirable inductance than

other types of resistor, although winding the wire in sections with alternately reversed

direction can minimize inductance. Other techniques employ bifilar winding, or a flat thin

former (to reduce cross-section area of the coil). For the most demanding circuits, resistors

with Ayrton-Perry winding are used.

Applications of wire wound resistors are similar to those of composition resistors

with the exception of the high frequency. The high frequency response of wire wound

resistors is substantially worse than that of a composition resistor.

Figure 3 : Wire Wound Resistor

2. CAPACITOR

A capacitor (originally known as a condenser) is a passive two-terminal electrical

component used to store energy electrostatically in an electric field. By contrast, batteries

store energy via chemical reactions. The forms of practical capacitors vary widely, but all

contain at least two electrical conductors separated by a dielectric (insulator); for example,

one common construction consists of metal foils separated by a thin layer of insulating film.

Capacitors are widely used as parts of electrical circuits in many common electrical

devices. When there is a potential difference (voltage) across the conductors, a static electric

field develops across the dielectric, causing positive charge to collect on one plate and

negative charge on the other plate. Energy is stored in the electrostatic field. An ideal

capacitor is characterized by a single constant value, capacitance. This is the ratio of the

electric charge on each conductor to the potential difference between them. The SI unit of

capacitance is the farad, which is equal to one coulomb per volt.

Figure 4 : Electrolytic capacitors of different voltages and capacitance

Figure 5 : Solid-body, resin-dipped 10 F 35 V Tantalum capacitors

Figure 6 : Types of capacitors and specifications

2.1. COLOUR CODING OF CAPACITORS

In general, a capacitor consists of two metal plates insulated from each other by a

dielectric. The capacitance of a capacitor depends primarily upon its shape and size and upon

the relative permittivity r of the medium between the plates. In vacuum, in air, and in most gases, r ranges from one to several hundred.

One classification of capacitors comes from the physical state of their dielectrics, which

may be gas (or vacuum), liquid, solid, or a combination of these. Each of these classifications

may be subdivided according to the specific dielectric used. Capacitors may be further

classified by their ability to be used in alternating-current (ac) or direct current (dc) circuits

with various current levels.

Capacitor Identification Codes:

There are no international agreements in place to standardize capacitor identification.

Most plastic film types (Figure7) have printed values and are normally in microfarads or if

the symbol is n, Nanofarads. Working voltage is easily identified. Tolerances are upper case

letters: M = 20%, K = 10%, J =5%, H = 2.5% and F = 1pF.

Figure 7 : Plastic Film Types

A more difficult scheme is shown in Figure 8 where K is used for indicating

Picofarads. The unit is picofarads and the third number is a multiplier. A capacitor coded

474K63 means 47 10000 pF which is equivalent to 470000 pF or 0.47 microfarads. K

indicates 10% tolerance. 50, 63 and 100 are working volts.

Figure 8 : Pico Farads Representation

Ceramic disk capacitors have many marking schemes. Capacitance, tolerance,

working voltage and temperature coefficient may be found. Capacitance values are given as

number without any identification as to units. (uF, nF, pF) Whole numbers usually indicate

pF and decimal numbers such as 0.1 or 0.47 are microfarads. Odd looking numbers such as

473 is the previously explained system and means 47 nF.

Figure 9 : Ceramic Disk capacitor

Figure 10 : Miscellaneous Capacitors

Electrolytic capacitor properties

There are a number of parameters of importance beyond the basic capacitance and

capacitive reactance when using electrolytic capacitors. When designing circuits using

electrolytic capacitors it is necessary to take these additional parameters into consideration

for some designs, and to be aware of them when using electrolytic capacitors.

ESR Equivalent series resistance: Electrolytic capacitors are often used in circuits where current levels are relatively high. Also under some circumstances and current

sourced from them needs to have low source impedance, for example when the

capacitor is being used in a power supply circuit as a reservoir capacitor. Under these

conditions it is necessary to consult the manufacturers datasheets to discover whether the electrolytic capacitor chosen will meet the requirements for the circuit. If

the ESR is high, then it will not be able to deliver the required amount of current in

the circuit, without a voltage drop resulting from the ESR which will be seen as a

source resistance.

Frequency response: One of the problems with electrolytic capacitors is that they have a limited frequency response. It is found that their ESR rises with frequency and

this generally limits their use to frequencies below about 100 kHz. This is particularly

true for large capacitors, and even the smaller electrolytic capacitors should not be

relied upon at high frequencies. To gain exact details it is necessary to consult the

manufacturers data for a given part.

Leakage: Although electrolytic capacitors have much higher levels of capacitance for a given volume than most other capacitor technologies, they can also have a higher

level of leakage. This is not a problem for most applications, such as when they are

used in power supplies. However under some circumstances they are not suitable. For

example they should not be used around the input circuitry of an operational

amplifier. Here even a small amount of leakage can cause problems because of the

high input impedance levels of the op-amp. It is also worth noting that the levels of

leakage are considerably higher in the reverse direction.

Ripple current: When using electrolytic capacitors in high current applications such as the reservoir capacitor of a power supply, it is necessary to consider the ripple

current it is likely to experience. Capacitors have a maximum ripple current they can

supply. Above this they can become too hot which will reduce their life. In extreme

cases it can cause the capacitor to fail. Accordingly it is necessary to calculate the

expected ripple current and check that it is within the manufacturers maximum ratings.

Tolerance: Electrolytic capacitors have a very wide tolerance. Typically this may be -50% to 80%. This is not normally a problem in applications such as decoupling or

power supply smoothing, etc. However they should not be used in circuits where the

exact value is of importance.

Polarization: Unlike many other types of capacitor, electrolytic capacitors are polarized and must be connected within a circuit so that they only see a voltage across

them in a particular way.

The physical appearance of electrolytic capacitor is as shown in Figure 11.The capacitors

themselves are marked so that polarity can easily be seen. In addition to this it is common for

the can of the capacitor to be connected to the negative terminal.

Figure 11 : Electrolytic capacitor

It is absolutely necessary to ensure that any electrolytic capacitors are connected

within a circuit with the correct polarity. A reverse bias voltage will cause the centre oxide

layer forming the dielectric to be destroyed as a result of electrochemical reduction. If this

occurs a short circuit will appear and excessive current can cause the capacitor to become

very hot. If this occurs the component may leak the electrolyte, but under some

circumstances they can explode. As this is not uncommon, it is very wise to take precautions

and ensure the capacitor is fitted correctly, especially in applications where high current

capability exists.

3. COLOUR CODING OF INDUCTORS

Inductor is just coil wound which provides more reactance for high frequencies and low

reactance for low frequencies. Moulded inductors follow the same scheme except the units

are usually micro-henries. A brown-black-red inductor is most likely a 1000 uH. Sometimes

a silver or gold band is used as a decimal point. So a red-gold-violet inductor would be a 2.7

uH. Also expect to see a wide silver or gold band before the first value band and a thin

tolerance band at the end. The typical Colour codes and their values are shown in Figure 12.

1000uH (1millihenry), 2% 6.8 uH, 5%

Figure 12 : Typical inductors Color coding and their values.

4. STUDY OF CRO

An oscilloscope is a test instrument which allows us to look at the 'shape' of electrical

signals by displaying a graph of voltage against time on its screen. It is like a voltmeter with

the valuable extra function of showing how the voltage varies with time. A graticule with a

1cm grid enables us to take measurements of voltage and time from the screen. The graph,

usually called the trace, is drawn by a beam of electrons striking the phosphor coating of the

screen making it emit light, usually green or blue. This is similar to the way a television

picture is produced.

Oscilloscopes contain a vacuum tube with a cathode (negative electrode) at one end to

emit electrons and an anode (positive electrode) to accelerate them so they move rapidly

down the tube to the screen. This arrangement is called an electron gun. The tube also

contains electrodes to deflect the electron beam up/down and left/right. The electrons are

called cathode rays because they are emitted by the cathode and this gives the oscilloscope its

full name of cathode ray oscilloscope or CRO.

A dual trace oscilloscope can display two traces on the screen, allowing us to easily

compare the input and output of an amplifier for example. It is well worth paying the modest

extra cost to have this facility.

4.1. BASIC OPERATION:

Figure 13 : Internal Block Diagram of CRO

Setting up an oscilloscope:

Oscilloscopes are complex instruments with many controls and they require some

care to set up and use successfully. It is quite easy to 'lose' the trace off the screen if controls

are set wrongly. There is some variation in the arrangement and labelling of the many

controls.

The following type of trace is observed on CRO after setting up, when there is no

input signal connected.

Figure 14 : Absence of input signal

Connecting an oscilloscope:

The Y INPUT lead to an oscilloscope should be a co-axial lead and the figure 15

shows its construction. The central wire carries the signal and the screen is connected to earth

(0V) to shield the signal from electrical interference (usually called noise).

Figure 15 : Construction of a co-axial lead

Most oscilloscopes have a BNC socket for the y input and the lead is connected with

a push and twist action, to disconnect we need to twist and pull.

Obtaining a clear and stable trace:

Once if we connect the oscilloscope to the circuit, it is necessary to adjust the controls

to obtain a clear and stable trace on the screen in order to test it.

The Y AMPLIFIER (VOLTS/CM) control determines the height of the trace. Choose a setting so the trace occupies at least half the screen height, but does not disappear

off the screen.

The TIMEBASE (TIME/CM) control determines the rate at which the dot sweeps across the screen. Choose a setting so the trace shows at least one cycle of the signal

across the screen. Note that a steady DC input signal gives a horizontal line trace for

which the time base setting is not critical.

The TRIGGER control is usually best left set to AUTO.

The trace of an AC signal with the oscilloscope controls correctly set is as shown in

Figure 16.

Figure 16 : Stable waveform

Measuring voltage and time period:

The trace on an oscilloscope screen is a graph of voltage against time. The shape of

this graph is determined by the nature of the input signal. In addition to the properties

labelled on the graph, there is frequency which is the number of cycles per second. The

diagram shows a sine wave but these properties apply to any signal with a constant shape.

Figure 17 : Measurement of amplitude and time period

Amplitude is the maximum voltage reached by the signal. It is measured in volts. o Peak voltage is another name for amplitude. o Peak-peak voltage is twice the peak voltage (amplitude). When reading an

oscilloscope trace it is usual to measure peak-peak voltage.

Time period is the time taken for the signal to complete one cycle. It is measured in seconds (s), but time periods tend to be short so milliseconds (ms) and microseconds

(s) are often used. 1ms = 0.001s and 1s = 0.000001s.

Frequency is the number of cycles per second. It is measured in hertz (Hz), but frequencies tend to be high so kilohertz (kHz) and megahertz (MHz) are often used.

I. Voltage: Voltage is shown on the vertical y-axis and the scale is determined by the Y AMPLIFIER (VOLTS/CM) control. Usually peak-peak voltage is measured because

it can be read correctly even if the position of 0V is not known. The amplitude is half

the peak-peak voltage.

Voltage = distance in cm volts/cm

II. Time period: Time is shown on the horizontal x-axis and the scale is determined by the TIMEBASE (TIME/CM) control. The time period (often just called period) is the

time for one cycle of the signal. The frequency is the number of cycles per second

frequency = 1/time period.

Time = distance in cm time/cm

4.2. SCIENTECH 801 EASYSCOPE

4.2.1. TECHNICAL SPECIFICATIONS

Operating Modes:

Channel 1,

Channel 2,

Channel 1 & 2 alternate or chopped (approximately 350 kHz),

X - Y (Ratio 1:1 Input via CH2), Add/ Sub CH1 CH2, Invert CH2.

Vertical deflection (Y):

(Identical channels)

Bandwidth: DC - 30MHz (-3dB)

Rise Time: 12ns (approximately).

Deflection coefficients:

Micro-controller based 12 calibrated steps 5 mV/Div 20 V/Div (1-2-5 sequence). Electronic Control Display on 32 character backlit Alphanumeric LCD.

Accuracy: 3%

Input Impedance: 1M | | 30pF (approximately) Input: BNC Connector

Input coupling: DC-AC-GND

Maximum Input voltage: 400V (DC + Peak AC).

Time Base:

Time coefficients: Micro-controller based 18 calibrated steps, 0.5us/Div - 0.2 s/Div

(1-2-5 sequence) with magnifier x10 to 50 ns/Div, with variable control to 20ns/Div.

Electronic control display on 32 character backlit Alphanumeric LCD.

Accuracy: 3% (in cal position)

Trigger System:

Modes: Auto / Level

Source: CHI, CHII, Alt CHI/CHII, Ext.

Slope: Positive or Negative

Sensitivity: Internal 5mm, External 0.8V (Approximately).

Trigger Bandwidth: 40MHz.

Horizontal Deflection (X):

Bandwidth: DC - 3MHz (-3 dB).

X-Y mode: Phase Shift < 3 at 60 KHz.

Deflection coefficients: Micro-controller based 12 calibrated steps 5 mV/Div-

20V/Div (1-2-5 sequence). Electronic Control Display on 32 character backlit

Alphanumeric LCD.

Input Impedance: 1M | | 30pF (approximately)

Input: BNC Connector

Input coupling: DC-AC-GND

Maximum Input voltage: 400 V (DC +Peak AC)

General Information:

Cathode Ray Tube: 140mm Rectangular tube with internal graticule. P31 Phosphor

Accelerating potential: 2KV (approximately)

Display: 8 x 10cm

Trace Rotation: Adjustable on front panel

Calibrator: Square Wave Generator 1kHz (approximately), 0.2Vpp 1% for probe

compensation.

Z Modulation: TTL level

USB Interface (optional): For remote control settings of Volt/Div. & Time/Div.

Stabilized Power Supply:

All operating voltages including the EHT

Power Supply:

230V 10%, 50Hz.

Power Consumption:

45VA (approximately)

Operating Temperature:

0-40C; 80% RH

4.2.2. PANEL CONTROLS

Figure 18 : Panel Diagram

1. Power On/Off: Rocker switch for supplying power to instrument. 2. X10: Switch when pushed gives 10 times magnification of the X signal. 3. XY: Switch when pressed cuts off the time base & allows access to the external

horizontal signal to be fed through CH2 (used for X - Y display).

4. CH1/ 2: Switch selects channel & trigger source (released Trig 1/ 2 CH1 & pressed CH2).

5. Mono/ Dual: Switch selects Mono or Dual trace operation. 6. Alt/ Chop/ Add: Switch selects alternate or chopped in Dual mode. If Mono is

selected then this switch enables addition or subtraction of channel i.e.CH1 CH2.

7. Ext: Switch when pressed allows external triggering signal to be fed from the socket marked Trigger Input (25).

8. Alt: Selects alternate trigger mode from CH1 & CH2.In this mode both the signals are synchronized.

9. Slope (+/-): Switch selects the slope of triggering, whether positive going or negative going.

10. Auto/Level: Switch selects Auto/Level position. Auto is used to get trace when no signal is fed at the input. In Level position the trigger level can be varied from the

positive peak to negative peak with Level Control.

11. Level: Controls the trigger level from peak to peak amplitude of signal. 12. X Shift: Controls horizontal position of the trace. 13. TB Var: Controls the time speed in between two steps of Time/Div switch. For

calibration put this pot fully anticlockwise at Cal position.

14. Intensity: Controls the brightness of the trace. 15. TR: Trace Rotation controls the alignment of the trace with graticule (screw driver

adjustment).

16. Focus: Controls the sharpness of the trace. 17. DC/AC/GND: Input coupling switch for each channel. In AC the signal is coupled

through 0.1MFD capacitor.

18. CH1 (Y) & : BNC connectors serve as input connection for CH2 (X) CH1 & CH2 Channel 2 input connector also serves as horizontal external Input.

19. Invert CH2: Switch when pressed invert polarity of CH2. 20. Cal Out: Socket provided for square wave output 200mV used for probe

compensation and checking vertical sensitivity, etc.

21. Digital Readout: LCD window for displaying Digital Readout for Volt/Div. & Time/Div. settings.

22. Y Shift 1 & 2: Controls provided for vertical deflection of trace for each channel. 23. Volts/Div.: Switch selects Volt/Div. step for CH1 & CH2 24. Time /Div : Switch selects Time/Div. steps. 25. Trigger Input: Socket provided to feed external trigger signal in External Trigger

mode.

5. STUDY OF FUNCTION GENERATOR

A function generator is a device that can produce various patterns of voltage at a variety

of frequencies and amplitudes. It is used to test the response of circuits to common input

signals. The electrical leads from the device are attached to the ground and signal input

terminals of the device under test.

Figure 19 : A typical low-cost function generator

Features and controls:

Most function generators allow the user to choose the shape of the output from a

small number of options.

Square wave - The signal goes directly from high to low voltage. The duty cycle of a signal refers to the ratio of high voltage to low voltage time in a square wave signal

Figure 20 : Square Wave

.Sine wave - The signal curves like a sinusoid from high to low voltage.

Figure 21: Sine Wave

Triangle wave - The signal goes from high to low voltage at a fixed rate.

Figure 22 : Triangular Wave

The amplitude control on a function generator varies the voltage difference between

the high and low voltage of the output signal. The direct current (DC) offset control on a

function generator varies the average voltage of a signal relative to the ground.

The frequency control of a function generator controls the rate at which output signal

oscillates. On some function generators, the frequency control is a combination of different

controls. One set of controls chooses the broad frequency range (order of magnitude) and the

other selects the precise frequency. This allows the function generator to handle the

enormous variation in frequency scale needed for signals.

How to use a function generator

After powering on the function generator, the output signal needs to be configured to

the desired shape. Typically, this means connecting the signal and ground leads to an

oscilloscope to check the controls. Adjust the function generator until the output signal is

correct, then attach the signal and ground leads from the function generator to the input and

ground of the device under test. For some applications, the negative lead of the function

generator should attach to a negative input of the device, but usually attaching to ground is

sufficient.

5.1. AD 202S Signal Generator

Figure 23 : AD 202S Signal Generator from ADD

6. STUDY OF REGULATED POWER SUPPLY

There are many types of power supply. Most are designed to convert high voltage AC

mains electricity to a suitable low voltage supply for electronic circuits and other devices. A

power supply can by broken down into a series of blocks, each of which performs a

particular function. For example a 5V regulated supply:

Figure 24 : Block Diagram of Regulated power supply

Each of the blocks is described in more detail below:

Transformer: Steps down high voltage AC mains to low voltage AC.

Rectifier: Converts AC to DC, but the DC output is varying.

Filter: Smoothens the DC from varying greatly to a small ripple.

Regulator: Eliminates ripple by setting DC output to a fixed voltage.

Dual Supplies:

Some electronic circuits require a power supply with positive and negative outputs as well as

zero volts (0V). This is called a 'dual supply' because it is like two ordinary supplies

connected together as shown in the diagram. Dual supplies have three outputs, for example a

9V supply has +9V, 0V and -9V outputs.

Figure 25 : Dual Supply

6.1. Analog & Digital Devices (ADD) APS52

Voltage : Variable voltage upto 30V DC

Current : Maximum current rating of 2A

Figure 26 : Dual Power Supply ADD APS52D

7. TYPES OF CIRCUIT BOARD

Breadboard: This is a way of making a temporary circuit, for testing purposes or to try out an idea. No soldering is required and all the components can be re-used

afterwards. It is easy to change connections and replace components. Almost all the

electronic projects started life on a breadboard to check that the circuit worked as

intended. The following figure depicts the appearance of Bread board in which the

holes in top and bottom stribes are connected horizontally that are used for power

supply and ground connection conventionally and holes on middle stribes connected

vertically.

Figure 27 : Breadboard