1

CONTENTS

I. VOLTAGE REGULATED DC POWER SUPPLY (+/-5 V DC)

1. Introduction………………………………………………………………3

a) Definition of power supply

b) Aim of the project.

2. Designing of Circuits…………………………………………………….4

a) Circuit diagram

b) Layout diagram

c) Components used and their specifications

d) Function of each component.

e) Designing Procedure

3. Observations…………………………………………………………….11

4. Conclusion………………………………………………………………11

II. MULTI-VIBRATOR USING NE 555 ( ASTABLE AND

MONOSTABLE)

1. Introduction………………………………………………………………12

a) Definition of Multi-vibrator

b) Types of Multi-vibrator

c) Uses of Multi-vibrator

d) Aim of the project

2. Designing of circuits……………………………………………………..13

a) Circuit Diagram

b) Layout diagram

c) Components used and their specifications

d) Function of each component

e) Designing Procedure

3. Observations and Calculations…………………………………………….19

2

4. Conclusion………………………………………………………………20

III. DESIGN OF SECOND ORDER ACTIVE LOW PASS, HIGH PASS

AND BAND PASS FILTER.

1. Introduction……………………………………………………………..21

a) Definition of Filter

b) Types of Filter

c) Uses of Filter

d) Aim of the project

2. Designing of Circuits……………………………………………………23

a) Circuit diagrams

b) Layout diagrams

c) Components used and their specifications

d) Designing Procedure

3. Observations and Calculations………………………………………….27

4. Results…………………………………………………………………..28

.

5. Discussions……………………………………………………………...31

6. Conclusion………………………………………………………………33

7. Graphs

3

I. VOLTAGE REGULATED DC POWER SUPPLY (+/-5VDC)

INTRODUCTION

Definition of Power Supply

Power Supply is an electrical device which supplies power to one or more electrical

loads. A regulated power supply is one that controls the output voltage or current to a

specific value; the controlled value is held nearly constant despite of variations in either

load current or the voltage supplied by the power supplies energy source.

Types of Power Supply

There are various types of Power supply such as:

1) Battery

2) DC Power supply

3) AC Power supply

4) Switched Mode Power Supply

5) Programmable Power Supply

6) Uninterrupted Power Supply

7) High Voltage Power Supply, etc.

Aim of the Project

To design a Voltage regulated DC Power Supply of rating +/- 5 Volts DC.

.

4

DESIGNING OF CIRCUITS:

Circuit Diagram:

5

Layout Diagram:

The connections on the opposite side of the vero board are horizontal, i.e the copper

cladding runs from left to right.

6

Components used and their specifications:

1. Transformer

2. Diode

3. Capacitor

4. IC-7805 & IC-7905

5. Resistance

6. Verro-board

NAME TYPE QUANTITY

Transformer (9-0-9)V 1

Diode 1N4007 4

Capacitor 1000µF,50V &

100µF,50V

2

2

IC-7805 - 1

IC-7905 - 1

Resistors 10KΩ,1/2W 2

Veroboard - 1

Function of each component:

Transformer:

A transformer is a device that transfers electrical energy from one

circuit to another through inductively coupled conductors—the transformer's coils. A

varying current in the first or primary winding creates a varying magnetic flux in the

transformer's core and thus a varying magnetic field through the secondary winding. If a

load is connected to the secondary, an electric current will flow in the secondary winding

and electrical energy will be transferred from the primary circuit through the transformer

to the load. In an ideal transformer, the induced voltage in the secondary winding (Vs) is

in proportion to the primary voltage (Vp), and is given by the ratio of the of turns in the

secondary (Ns) to the number of turns in the primary (Np) as follows:

Vs/Vp=Ns/Np

7

By appropriate selection of the ratio of turns, a transformer thus allows an alternating

current (AC) voltage to be "stepped up" by making Ns greater than Np, or "stepped

down" by making Ns less than Np.

Application:

1. A major application of transformers is to increase voltage before transmitting

electrical energy over long distances through wires.

2. The transformer also electrically isolates the end user from contact with the

supply voltage.

3. Signal and audio transformers are used to couple stages of amplifiers and to match

devices such as microphones and record players to the input of amplifiers. Audio

transformers allowed telephone circuits to carry on a two-way conversation over a single

pair of wires.

Diodes:

The 1N4001 series (or 1N4000 series) is a family of popular 1.0 amp general purpose

silicon rectifier diodes commonly used in AC adapters for common household

appliances. Blocking voltage varies from 50 to 1000 volts. This diode is made in an axial-

lead DO-41 plastic package. These are fairly low-speed rectifier diodes, being inefficient

for square waves of more than 15 kHz. The series was second sourced by many

manufacturers.

Applications:

These are fairly low-speed rectifier diodes, being inefficient for square waves of more

than 15 kHz. The series was second sourced by many manufacturers, popular series for

higher current applications, up to 3 A.

Capacitors:

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

component used to store energy in an electric field. The forms of practical capacitors

vary widely, but all contain at least two electrical conductors separated by a dielectric

(insulator). 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 wholly characterized by a constant capacitance C, defined as the ratio of

charge ±Q on each conductor to the voltage V between them:

C=Q/V

8

Applications:

Energy storage:

1) A capacitor can store electric energy when disconnected from its charging circuit, so it

can be used like a temporary battery.

2) Pulsed power and weapons:

Groups of large, specially constructed, low-inductance high-voltage capacitors

(capacitor banks) are used to supply huge pulses of current for many pulsed power

applications. These include electromagnetic forming, Marx generators, pulsed lasers

(especially TEA lasers), pulse forming networks, radar, fusion research, and particle

accelerators.

3) Power conditioning:

Reservoir capacitors are used in power supplies where they smooth the output of a full

or half wave rectifier.

4) Signal processing:

The energy stored in a capacitor can be used to represent information, either in

binary form, as in DRAMs, or in analogue form, as in analog sampled filters and CCDs.

5) Tuned circuits:

Capacitors and inductors are applied together in tuned circuits to select information in

particular frequency bands. For example, radio receivers rely on variable capacitors to

tune the station frequency. Speakers use passive analog crossovers, and analog equalizers

use capacitors to select different audio bands.

IC-7805 & IC-7905:

The 78xx (sometimes LM78xx) is a family of self-contained fixed linear voltage

regulator integrated circuits. The 78xx family is commonly used in electronic circuits

requiring a regulated power supply due to their ease-of-use and low cost. For ICs within

the family, the xx is replaced with two digits, indicating the output voltage (for example,

the 7805 has a 5 volt output, while the 7812 produces 12 volts). The 78xx line are

positive voltage regulators: they produce a voltage that is positive relative to a common

ground. There is a related line of 79xx devices which are complementary negative

voltage regulators. 78xx and 79xx ICs can be used in combination to provide positive and

negative supply voltages in the same circuit. 78xx ICs have three terminals

9

Advantages:

1)78xx series ICs do not require additional components to provide a constant, regulated

source of power, making them easy to use, as well as economical and efficient uses of

space.

2)78xx series ICs have built-in protection against a circuit drawing too much power.

They have protection against overheating and short-circuits, making them quite robust

in most applications. In some cases, the current-limiting features of the 78xx devices can

provide protection not only for the 78xx itself, but also for other parts of the circuit.

Disadvantage:

The input voltage must always be higher than the output voltage by some minimum

amount (typically 2 volts).This can make these devices unsuitable for powering some

devices from certain types of power sources

As they are based on a linear regulator design, the input current required is always the

same as the output current. As the input voltage must always be higher than the output

voltage, this means that the total power (voltage multiplied by current) going into the

78xx will be more than the output power provided. The extra input power is dissipated as

heat. This means both that for some applications an adequate heat sink must be provided,

and also that a (often substantial) portion of the input power is wasted during the process,

rendering them less efficient than some other types of power supplies. When the input

voltage is significantly higher than the regulated output voltage (for example, powering a

7805 using a 24 volt power source), this inefficiency can be a significant issue.

Resistance:

A linear resistor is a linear, 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 relation is represented by

Ohm's law: R=V/I

Applications:

1) Resistors are common elements of electrical networks and electronic circuits and are

ubiquitous in most electronic equipment.

2) Resistors are also implemented within integrated circuits, particularly analog devices,

and can also be integrated into hybrid and printed circuits.

10

Veroboard:

Stripboard is a widely-used type of electronics prototyping board characterized by a 0.1

inch (2.54 mm) regular (rectangular) grid of holes, with wide parallel strips of copper

cladding running in one direction all the way across one side of the board. It is usually

known by the name Veroboard, which is a trademark, in the UK, of British company

Vero Technologies Ltd, & Pixel Print LTD Canada. In using the board, breaks are made

in the tracks, usually around holes, to

divide the strips into multiple electrical nodes. With care, it is possible to break between

holes to allow for components that have two pin rows only one position apart such as

twin row headers for IDCs. Stripboard holes are drilled on 0.1 inch (2.54 mm) centers.

This spacing allows components having pins with a 0.1 inch (2.54 mm) spacing to be

inserted. Compatible parts include DIP ICs, sockets for ICs, some types of connectors,

and other devices.

Applications:

This spacing allows components having pins with a 0.1 inch (2.54 mm) spacing to be

inserted.

Designing Procedure:

1) A vero board is taken where we make one row as positive AC, one as Ground and

another as negative AC, all these three connections are derived from the step

down transformer.

2) A bridge rectifier is constructed on the board from wher we get positive DC and

negative DC( both these potentials are with respect to each other).

3) We connect capacitors C1 and C2 as shown in the circuit diagram

4) Transistors 7805 and 7809 are placed on the board as per connections shown in the

circuit diagram.

5) Capacitors C3 and C4 are connected as shown in the circuit diagram.

6) Resistors R1 and R2 are connected across the above mentioned capacitors to get the

potential differences between the terminals.

11

OBSERVATIONS:

The output across the two resistances, measured by a multi-meter, gave a reading of 5 V

DC.

CONCLUSION:

The experiment performed was successful. Objective to produce a regulated +/-5 V DC

Power Supply was realized.

12

II. MULTI-VIBRATOR USING NE 555 (ASTABLE AND

MONOSTABLE)

INTRODUCTION:

Definition of Multi-vibrator:

Commonly known as Timer, a timer is a specialized type of a clock that can be used to

control the sequence of an event or process. Timers can be mechanical, electro-

mechanical, electrical as well as software based. We use IC NE 555 to realize the

multivibrator.

Types of Multi-vibrator:

1) Monostable multi-vibrator: in this mode, the 555 functions as a "one-shot" pulse

generator. Applications include timers, missing pulse detection, bouncefree

switches, touch switches, frequency divider, capacitance measurement, pulse-

width modulation (PWM) and so on.

2) Astable multi-vibrator: free running mode: the 555 can operate as an oscillator.

Uses include LED and lamp flashers, pulse generation, logic clocks, tone

generation, security alarms, pulse position modulation and so on. Selecting a

thermistor as timing resistor allows the use of the 555 in a temperature sensor: the

period of the output pulse is determined by the temperature. The use of a

microprocessor based circuit can then convert the pulse period to temperature,

linearize it and even provide calibration means.

3) Bistable multi-vibrator or Schmitt trigger: the 555 can operate as a flip-flop, if the

DIS pin is not connected and no capacitor is used. Uses include bounce free

latched switches.

13

Uses of Multi-vibrators:

Timer circuits have been in vogue since a past few decades as these are extensively

used in various electronic devices. Pertaining to Biomedical Engineering field, timers

find extreme application in timing the X-Ray machine firing.

Aim of the Project:

To design a multivibrator circuit using IC NE 555 which displays Astable and

Monostable characteristics.

DESIGNING OF CIRCUITS:

Circuit diagram, Layout diagram and other details are thoroughly discussed in the

subsequent pages.

14

Circuit Diagram:

15

Layout Diagram:

The connections on the opposite side of the vero board is vertical, i.e the copper

cladding runs from top to bottom.

16

Components used and their specifications:

1) IC NE 555:

The 555 timer IC is an integrated circuit used in a variety of timer, pulse generation

and oscillator applications. The IC 555 has widespread use, because of its ease of

use, low price and good stability.

These specifications apply to the NE555. Other 555 timers can have different

specifications depending on the grade (military, medical, etc).

Supply voltage (VCC) 4.5 to 15 V

Supply current (VCC = +5 V) 3 to 6 mA

Supply current (VCC = +15 V) 10 to 15 mA

Output current (maximum) 200 mA

Maximum Power dissipation 600 mW

Power Consumption (minimum) 30 mW@5V, 225 mW@15V

Operating temperature 0 to 70 degree C

2) Non-polar capacitors:

Two capacitors of rating 0.1 uF , 0.01 uF each.

3) Resistance:

Two resistances of 10k ohm and one of 5.6k ohm.

17

Function of each component:

IC NE 555:

The IC design was proposed in 1970 by Hans R. Camenzind and Jim Ball. After

prototyping, the design was ported to the Monochip analogue array, incorporating

detailed design by Wayne Foletta and others from Qualidyne Semiconductor.

Depending on the manufacturer, the standard 555 package includes over 20

transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin mini

dual-in-line package.

The NE555 parts were commercial temperature range, 0 °C to +70 °C, and the SE555

part number designated the military temperature range, −55 °C to +125 °C. These

were available in both high-reliability metal can (T package) and inexpensive epoxy

plastic (V package) packages. Thus the full part numbers were NE555V, NE555T,

SE555V, and SE555T. It has been hypothesized that the 555 got its name from the

three 5 kΩ resistors used within Low-power versions of the 555 are also available,

such as the 7555 and CMOS TLC555. The 7555 is designed to cause less supply

glitching than the classic 555 and the manufacturer claims that it usually does not

require a "control" capacitor and in many cases does not require a decoupling

capacitor on the power supply. Such a practice should nevertheless be avoided,

because noise produced by the timer or variation in power supply voltage might

interfere with other parts of a circuit or influence its threshold voltages. The pin

diagram is given below:

Pin Name Purpose

1 GND- Ground, low level (0 V)

2 TRIG- OUT rises, and interval starts, when this input falls below 1/3 VCC.

3 OUT- This output is driven to +VCC or GND.

4 RESET- A timing interval may be interrupted by driving this input to GND.

18

5 CTRL- "Control" access to the internal voltage divider (by default, 2/3 VCC).

6 THR- The interval ends when the voltage at THR is greater than at CTRL.

7 DIS- Open collector output; may discharge a capacitor between intervals.

8 VCC - Positive supply voltage is usually between 3 and 15 V.

In the monostable mode, the 555 timer acts as a ―one-shot‖ pulse generator. The pulse

begins when the 555 timer receives a signal at the trigger input that falls below a third of

the voltage supply. The width of the output pulse is determined by the time constant of an

RC network, which consists of a capacitor (C) and a resistor (R). The output pulse ends

when the voltage on the capacitor equals 2/3 of the supply voltage. The output pulse

width can be lengthened or shortened to the need of the specific application by adjusting

the values of R and C.

In astable mode, the 555 timer puts out a continuous stream of rectangular pulses having

a specified frequency. Resistor R1 is connected between VCC and the discharge pin (pin 7)

and another resistor (R2) is connected between the discharge pin (pin 7), and the trigger

(pin 2) and threshold (pin 6) pins that share a common node. Hence the capacitor is

charged through R1 and R2, and discharged only through R2, since pin 7 has low

impedance to ground during output low intervals of the cycle, therefore discharging the

capacitor.

Applications:

This timer IC can be used for triggering applications.

It can also be used as a square wave generator.

It can be used as astable multi-vibrator and monostable multi-vibrator.

Designing Procedure:

1) A vero board is taken. We make one row of the board to be the +Vcc, one row to be

the ground.

2) The components are gradually placed as shown in the circuit diagram. First we place

the 2 ICs having a gap of 3 points between them. This is done so that connections

other than ground can be established.

3) Interconnections between various terminals of the IC are made as shown in the

circuit diagram.

19

4) Terminal 8 and 4 of the astable multivibrator is connected to +Vcc. Terminals 2, 5 and

6 are connected to ground through capacitors and terminal 1 is directly connected

to the ground.

5) Similar procedure is followed for the mono stable multivibrator. Here the input

terminal is connected to the output terminal of astable multivibrator.

6) Terminals 4 and 8 are connected to +Vcc.

7) Interconnections between various terminals are made according to the circuit

diagram.

8) Terminals 5 and 6 are connected to the ground via capacitors and terminal 1 is

directly connected to the ground.

9) The final output is obtained from terminal 3.

OBSERVATIONS AND CALCULATIONS:

Astable:

Relevant equations:

TTotal = Ton + TOff

Ton = 0.69( RA + RB )

TOff = 0.69( RA + 2RB )

Duty Cycle = TON / TTotal X 100%

Frequency = 1/ TTotal

where RA = 5.6 k ohm, RB = 10 k ohm, C = 0.1 uF.

20

Theoretical values obtained: Practical Values obtained:

Ton = 1.07 x 10-3 sec Ton = 1.2 x 10-3 sec

TOff = 6.9 x 10-4 sec TOff = 7 x 10-4 sec

TTotal = 1.76 x 10-3 sec TTotal = 1.9 x 10-3 sec

Duty Cycle = 60.7% Duty Cycle = 63.16%

Frequency = 568.18 Hz. Frequency = 526.32 Hz

Monostable:

Ton = 1.1R x C, where R = 10 k ohm, C = 0.1 uF .

Theoretical Value obtained: Practical Value obtained:

Ton = 1.1 x 10-3 sec Ton = 1.4 x 10-3 sec

CONCLUSION:

.

The experiment performed was successful. The objective to realize a Monostable

multivibrator from a astable multivibrator was fully realized.

21

III. DESIGN OF SECOND ORDER ACTIVE LOW PASS, HIGH PASS

AND BAND PASS FILTERS

INTRODUCTION

DEFINITION OF FILTER

Electronic filters are electronic circuits which perform signal processing functions

specifically to remove unwanted frequency components from the signal, to enhance

wanted ones, or both.

TYPES OF FILTER:

Electronic filters can be classified as – a) Active Filter, b) Passive Filter

.

Active Filters – Active filters are implemented using a combination of passive and

active (amplifying) components, and require an outside power source. Operational

amplifiers are frequently used in active filter designs. These can have high Q factor, and

can achieve resonance without the use of inductors. However, their upper frequency limit

is limited by the bandwidth of the amplifiers used.

Passive Filters – These are basic electronic filters comprised of passive elements

like Resistor, Capacitor and Inductor. These do not have active components and have

limited application. But these are the fundamental part of constructing an active filter.

In other way, electronic filters can be classified as – i) Low-Pass Filter, ii) High-

Pass Filter, iii) Band-Pass Filter, iv) Band-Reject Filter.

Low-Pass Filter – A Low-Pass filter is a filter that passes low-frequency signals

but attenuates (reduces the amplitude of) signals with frequencies higher than the cut-off

frequency. The actual amount of attenuation for each frequency varies from filter to filter.

It is sometimes called a High-Cut filter, or Treble-Cut filter when used in audio

applications. A Low-Pass filter is the opposite of a High-Pass filter and a band-pass filter

is a combination of a low-pass and a High-Pass filter.

22

High-Pass Filter – A High-Pass filter is an Linear Time-Invarient filter that passes

high frequency well but attenuates (reduces the amplitude of) frequencies lower than the

cut-off frequency. The actual amount of attenuation for each frequency is a design

parameter of the filter. It is sometimes called a Low-Cut filter. the terms Bass-Cut filter

and Rumble filter are also used in audio applications.

Band-Pass Filter – A Band-Pass filter is a filter that passes frequencies within a

certain range and rejects (attenuates) frequencies outside the range. An example of an

analogue electronic band-pass filter is a RLC circuit (a resistor-inductor-capacitor

circuit). These filters can also be created by combining a Low-Pass filter with a High-

Pass filter.

Band-Reject Filter – A Band-Reject filter circuit is used to block the passage of

current for a narrow band of frequencies, while allowing current to flow at all frequencies

above or below this band. This type of a filter is also known as a Band-Suspension or

Band-Stop filter.

USES OF FILTERS :

Low-pass Filter – Electronic Low-Pass filters are used to drive subwoofers and other

types of loudspeakers. Radio-transmitters use Low-Pass filters to block harmonic

emissions. The tone knob found on many electric guitars is a Low-Pass filter used to

reduce the amount of treble in the sound.

High-Pass Filter – Electronic High-Pass filters could be used as a part of an audio

crossover to direct to a tweeter. High-Pass filters are also used for AC coupling at the

input and the output of amplifiers. Rumble filters are High-Pass filters which removes the

unwanted sounds near the lower end of the audible range.

Band-Pass Filter – Outside the electronics and signal processing, one example of the use

of Band-Pass filters is in the atmospheric sciences.

AIM OF THE PROJECT:

To design Second order Active Low Pass, High Pass and Band Pass Filters.

23

DESIGNING OF CIRCUITS:

Circuit diagram:

24

Layout Diagram:

The connections on the opposite side of the vero board are vertical, i.e the copper

cladding runs from top to bottom.

25

Components used and their specifications:

1) Bread Board

2) Wires

3) Cutter and wire stripper

4) Twizzer

5) Funtion Generator

6) CRO

7) Multimeter

COMPONENTS No. PURPOSES SPECIFICATIONS

Resistance 8 For High-Pass and Low-Pass

filter and amplifier

0.25 watt, 1% tolerance,

180k for High-Pass and 18k

for Low-Pass filter, 10k

Capacitance 4 For High-Pass and Low-Pass

filter

0.01 microfarad

Function Generator 1 For input 230 volt, 50Hz, 13 VA

Oscilloscope 1 For output 230 volt, 50Hz, 25mHz 2

channel, 4 trace

Dual Power Supply 1 For power supply 30 volt, 3 A

Multimeter 1 For measuring the value of

resistances and capacitances

200 ohm to 2000 ohm, 200

mv to 200 v, 2 nfarad to 20

microfarad

IC 741 2 amplifier Input offset voltage 5 volt,

CMRR 70

Designing Procedure:

i. First we take the vero board. The vero board has two terminal strips, four bus

strips and three binding posts. Each bus strips has two rows of contacts. Each

of the two rows of contacts on the bus strips are a node. That is, every contact

along a row on a bus strip is connected together, inside the vero board. Bus

strips are used primarily for power supply connections but are also used for

any node requiring a large number of connections. Each terminal strip has 60

rows and 5 columns of contacts on each side of the center gap. Each row of 5

contacts is a node.

26

ii. Then, we place the components at the lines which vertically connected to each

other as the circuit diagram. Before this we measure resistance and

capacitance by a multimeter.

iii. The two IC’s 741 has 2 inputs ( pin 2 for inverting terminal and 3 for non-

inverting terminal) and 1 output(pin 6). Pin 7 and pin 4 are usually connected

to +vcc and –vcc.

iv. The ground connection from pin 2 and pin 3 are done by placing one terminal

of resistance to the vertically connected region of the bread board and the

vertically connected region is connected to the ground of dual power supply

source by a wire.

v. The +vcc and –vcc connection of pin 7 and 4 are done by the respective wires

which are connected to the +vcc and –vcc of power supply source.

vi. The output of the High-Pass filter is totally connected by a wire to the input of

Low-Pass filter to make a High-Pass filter.

vii. We apply an input from function generator to the input terminal of the High-

Pass filter where both of them are connected with each other by a wire and we

get an output pulse from the oscilloscope.

viii. From the pulse that we get from oscilloscope we measure the gain with

respect to the frequency and we plot the gain with respect to the frequency in

the graph. From the graphs we get the cut-off frequency of Band-Pass filter.

27

OBSERVATIONS AND CALCULATIONS:

THEORETICAL CONSIDERATIONS:

For Low-Pass filter :

Rf = 15kΩ, R’ = 15kΩ;

R1 = R2 = R=1.6kΩ ;

C1 = C2 = C=0.01µF ;

High cut-off frequency= 1/[2π√(R1R2C1C2 )] = 1/2πRC

= 1/(2π×1.6×103×0.01×10

-6) = 9947.2Hz; which can be approximated as 10kHz.

Gain(ALPF) = 1 + Rf/R’ = 2;

Filter slope = 40 dB/decade;

Bandwidth= 10 KHz

For High-Pass filters :

Rf = 15kΩ ; R’ = 15kΩ;

R1 = R2 = R=1.6kΩ;

C1 = C2 =C= 0.01µF ;

Low cut-off frequency= 1/[2π√(R1R2C1C2 )] = 1/2πRC

= 1/(2π×1.6×103×0.01×10

-6) = 994.72Hz; which can be approximated as 1KHz.

Gain(AHPF) = 1 + Rf/R’ = 2;

Filter slope = 40 dB/decade;

Bandwidth= 1KHz;

For Band-Pass filters :

Low cut-off frequency= fCH = 1KHz;

High cut-off frequency= fCL = 10 KHz;

28

Gain(ABPF) = ALPF + AHPF = 4

Low Pass filter slope = 40 dB/decade;

High Pass filter slope = 40 dB/decade;

Bandwidth= 9KHz.

RESULTS:

Frequency Response of Low-Pass filter

Vin = 1 Vp-p

SL. NO. FREQUENCY

(Hz) OUTPUT VOLTAGE

Vout (volts) GAIN = Vout/Vin GAIN

(in Db)

1 100 2 2 6.02

2 200 2 2 6.02

3 300 2 2 6.02

4 400 2 2 6.02

5 500 2 2 6.02

6 600 2 2 6.02

7 700 2 2 6.02

8 800 2 2 6.02

9 900 2 2 6.02

10 1k 2 2 6.02

11 2k 2 2 6.02

12 3k 2 2 6.02

13 4k 2 2 6.02

14 5k 2 2 6.02

15 6k 2 2 6.02

16 7k 2 2 6.02

17 8k 2 2 6.02

18 9k 1.9 1.9 5.57

19 10k 1.8 1.8 5.10

29

20 11k 1.6 1.6 4.08

21 12k 1.4 1.4 2.92

22 15k 1.0 1.0 0

23 18k 0.7 0.7 – 3.09

24 20k 0.6 0.6 – 4.44

25 25k 0.36 0.36 – 8.87

26 30k 0.24 0.24 – 12.39

27 40k 0.14 0.14 – 17.08

28 50k 0.10 0.10 – 20

29 60k 0.07 0.07 – 23.09

30 70k 50mv 0.05 – 26.02

31 80k 40mv 0.04 – 27.96

32 90k 35mv 0.035 – 29.12

33 100k 30mv 0.030 – 30.46

34 150k 20mv 0.020 – 33.98

35 200k 12mv 0.012 –38.42

Frequency Response of the High-Pass filter

Vin = 1 Vp-p

SL. NO. FREQUENCY

(Hz) OUTPUT VOLTAGE

Vout (volts) GAIN = Vout/Vin GAIN

(in Db)

1 100k 2 2 6.02

2 90k 2 2 6.02

3 80k 2 2 6.02

4 70k 2 2 6.02

5 60k 2 2 6.02

6 50k 2 2 6.02

7 40k 2 2 6.02

8 30k 2 2 6.02

9 20k 2 2 6.02

10 10k 2 2 6.02

11 9k 2 2 6.02

12 8k 2 2 6.02

13 7k 2 2 6.02

14 6k 2 2 6.02

30

15 5k 2 2 6.02

16 4k 2 2 6.02

17 3k 2 2 6.02

18 2k 2.2 2.2 6.85

19 1.5k 2.2 2.2 6.85

20 1k 1.8 1.8 5.10

21 900 1.6 1.6 4.08

22 800 1.4 1.4 2.02

23 700 1.2 1.2 1.58

24 600 0.8 0.8 – 1.92

25 500 0.6 0.6 – 4.44

26 400 0.4 0.4 – 7.96

27 300 0.3 0.3 – 10.46

28 200 0.16 0.16 – 15.92

29 150 0.12 0.12 – 18.42

30 100 0.06 0.06 – 24.44

31 50 0.03 0.03 – 30.46

Frequency Response of the Band-Pass filter

Vin = 1 Vp-p

SL. NO. FREQUENCY

(Hz) OUTPUT VOLTAGE

Vout (volts) GAIN = Vout/Vin GAIN

(in Db)

1 50 0.05 0.05 – 26.02

2 100 0.12 0.12 – 18.42

3 200 0.32 0.32 – 9.89

4 300 0.60 0.60 – 4.44

5 400 0.9 0.9 – 0.91

6 500 1.2 1.2 1.58

7 600 1.8 1.8 5.10

8 700 2.2 2.2 6.85

9 800 2.8 2.8 8.94

10 900 3.2 3.2 10.10

11 1k 3.6 3.6 11.13

12 1.5k 4.4 4.4 12.87

31

13 2k 4 4 12.04

14 3k 4 4 12.04

15 4k 4 4 12.04

16 5k 4 4 12.04

17 6k 4 4 12.04

18 7k 4 4 12.04

19 8k 4 4 12.04

20 9k 3.6 3.6 11.13

21 10k 3.6 3.6 11.13

22 20k 1.1 1.1 0.83

23 30k 0.5 0.5 – 6.02

24 40k 0.28 0.28 – 11.06

25 50k 0.20 0.20 – 13.98

26 60k 0.16 0.16 – 15.92

27 70k 0.10 0.10 – 20

28 80k 0.08 0.08 –21.94

29 90k 0.06 0.06 – 24.44

30 100k 0.05 0.05 –26.02

31 150k 0.03 0.03 –30.46

DISCUSSIONS:

LOW PASS FILTER:

PARAMETER

THEORETICAL VALUE

PRACTICAL VALUE

Cut-off Frequency 10 KHz 12 KHz

Slope 40 dB/decade 36 dB/decade

Bandwidth 10 KHz 12 KHz

32

HIGH PASS FILTER

PARAMETER

THEORETICAL VALUE

PRACTICAL VALUE

Cut-off Frequency 1 KHz 860 Hz

Slope 40 dB/decade 29 dB/decade

Bandwidth 1 KHz 0.86 KHz

BAND PASS FILTER

PARAMETER

THEORETICAL VALUE

PRACTICAL VALUE

Low Cut-off Frequency 1 KHz 520 Hz

High Cut-off frequency 10 KHz 17.5 KHz

High Pass filter slope 40 dB/decade 29 dB/decade

Low Pass filter slope 40 dB/decade 36 dB/decade

Bandwidth 9 KHz 16.98 KHz

33

CONCLUSION:

In this project the used electronic components does not possess perfect effective value or

quality. So there remains the lack of perfect value in the filter output. Thus, we can say

that the project of designing of 2nd

order active Low-Pass, High-Pass and Band-Pass

filters is successful.