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APROJECT REPORT

ON

SCHOOL / COLLEGE QUIZ BUZZER

SUBMITTED IN PARTIAL FULFILLMENT OF THE

REQUIREMENT FOR THE AWARD OF THE DEGREE

OF

BACHELOR OF ENGINEERING

INELECTRONICS AND COMMUNICATION ENGINEERING

Guided by: - Submitted by: -

Mr. Nilesh Parihar Sumit Kumar Dahiya

Lecturer (E.C.E) Narendra Bagoria

Final year (E.C.E.)

DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING

SOBHASARIA ENGINEERING COLLEGE, SIKAR

UNIVERSITY OF RAJASTHAN

2007-08

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CANDIDATE DECLARATION

This is to certify that work, which is being presented in the project entitled SCHOOL /

COLLEGE QUIZ BUZZER submitted by undersigned students of final year B.E. in

Electronics & Communication Engineering in partial fulfillment for award of degree of

bachelor of engineering is a record of our own work carried out by us guidance and

supervision of Mr. Nilesh Parihar (Lecturer), Department of Electronics &

communication Engineering.

This work has not submitted elsewhere for award of any other degree.

Date: 12/ 12/ 2007 ( )

Place: S.E.C.,Sikar Name: Sumit Kumar Dahiya

Enroll. No. 04/13030

( )

Name: Narendra Bagoria

Enroll. No.04/13050

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CERTIFICATE

THIS IS TO CERTIFY THAT THE WORK, WHICH IS BEING PRESENTED IN THE

PROJECT SCHOOL/COLLEGE QUIZ BUZZER SUBMITTED BY SUMIT

KUMAR DAHIYA AND NARENDRA BAGORIA, STUDENTS OF FINAL YEAR

B.E. IN ELECTRONICS & COMMUNICATION ENGNEERING AS A PARTIAL

FULFILLMENT FOR THE AWARD OF DEGREE OF BACHELOR OF ENGINEERING

IS A RECORD OF STUDENTS WORK CARRIED OUT BY HIM UNDER MY

GUIDANCE AND SUPERVISION.

THIS WORK HAS NOT BEEN SUBMITTED ELSEWHERE FOR THE AWARD OF

ANY OTHER DEGREE.

DATE: 12/ 12 / 2007 (----------------------)

PLACE: S.E.C., SIKAR PROJECT GUIDE

(Sh. NILESH PARIHAR) (Sh.K.B.SINGH)PROJECT INCHARGE (H.O.D OF E.C.E. DEPTT.)

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ACKNOWLEDGEMENT

Expressing gratitude is not just a ritual that has to be carried out. Rather it is an

opportunity to sincerely thank all those who extended their much-needed help.

It gives us immense pleasure in acknowledging the help we have received during

our tenure at Sobhasaria Engineering College. We owe our all the obligations and our

sincere feelings to our guide Mr. Nilesh Parihar (Lecturer, ECE) to provide us valuable

guidance and encouragement through out the stages of presentation of our project as well

as preparation of report. We regard him for all time he could devote for the project and for

helping us grasps the technical wiz-a-wiz of the SCHOOL / COLLEGE QUIZ

BUZZER. We gladly appreciate the time and patience they could spare their busyschedule.

We are highly obliged to Mr. K.B.Singh (H.O.D., ECE) for their appreciation.

At last but the most we would like to extend our thanks to all faculty members of

Department of Electronics & Communication Engineering, faculty ofCommunication

Lab, our friends and colleague for their support and cooperation.

( )

Sumit Kumar Dahiya

( )

Narendra Bagoria

(Final Year ECE)

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ABSTRACT

Manual buzzers used for quiz competitions in schools and colleges create a lot of

confusion in identifying the first respondent. Although there are circuits using PCs and

discrete ICs, they are either too expensive or limited to only a few numbers of players.

The quiz buzzer circuit given here can be used for up to eight players, which is

maximum in any quiz com-petition. The circuit uses IC 74LS373 and a few passive

components that are readily available in the market. The circuit can be divided into two

sections: power supply and quiz buzzer. Fig. 1 shows the power supply section. The

regulated 5V power supply for the quiz buzzer section is derived from AC mains. The

230V AC mains is stepped down to 7.5V AC by transformer X1, rectified by bridge

rectifier BR1, filtered by C1 and regulated by regulator IC1. Capacitor C2 bypasses ripples

in the regulator output.Fig. 2 shows the quiz buzzer section. At the heart of this section is

IC 74LS373, an octal latch that is used to transfer the logic state at data input pins D0

through D7 to the corresponding Q0 through Q7 outputs. Data pins D0 through D7 are

normally pulled low by resistors R1 through R8, respectively.One terminal of push-to-on

switches S1 through S8 is connected to +5V, while the other terminal is connected to the

respective data input pins.

The switches are to be extended to the players through cord wire. The torch bulbs

BL1 through BL8 can be housed in boxes with the front side of the boxes covered with a

white paper having the name or number of the contestant written over it for easy

identification. Place the boxes above the head level so that these can betseen by the

audience also.

When the power is switched on using switch S9 (provided terminals A and B of

both the power supply and quiz buzzer sections are interconnected), the circuit is ready to

use. Now all the switches (S1 through S8) are open and Q0 through Q7 outputs of IC

74LS373 are low. As a result, the gates of silicon-controlled rectifiers SCR1 through SCR8

are also low. As soon as a contestant momentarily presses his respective switch, the

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corresponding output data pin goes high. This triggers the corresponding SCR and the

respective bulb glows.

At the same time, the piezobuzzer (PZ1) sounds as transistor T1 conducts.

Simultaneously, the base of transistor T2 becomes high to make it conduct. Latch-enable

(LE) pin 11 of IC2 is tied to ground to latch all the Q0 through Q7 outputs. This restricts

further change in the output state due to any change in the state of switches S1 through S8

by any other contestant. Only one of the eight torch bulbs glows until the circuit is reset by

on/ off switch S9.

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INDEX

Chapter 1 Introduction 11.1 School / College Quiz Buzzer

1.2 Basic terms

Chapter 2 Component description 2-13

2.1 Introduction

2.2 7805 IC Voltage Regulator

2.2.1Definition of 741 pin function

2.3 74LS373 IC

2.3.1Definition of pin functions

2.3.2 Operating modes

2.3.2.1 Monostable mode

2.3.2.2 Astable mode

2.4 Silicon Controlled Rectifier (SCR)

2.5 Resistor

2.6 Transistor

2.6.1 Types of BJT transistor

2.6.1.1 NPN transistor

2.6.2.2 PNP transistor

2.6.2 Region of operation

2.7 Capacitor

2.8 Diode

2.9 Light Emitted Diode (LED)

Chapter 3 Versatile intercom system 14-16

3.1 The circuit

3.2 Construction

Conclusion 17-18

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References 19

Chapter: 1

INTRODUCTION

1.1 School / College Quiz Buzzer

The attraction of any game show depends on the visual effects. The way in which

they present different rounds makes the game shows effective. The good Quiz show always

contains one or more buzzer rounds.

The buzzer makes a round of a Quiz show 'fastest finger first '. The active buzzer

makes the team to first respond to the question. A common question will be asked for all

the teams in these rounds. The team which presses the buzzer first gets first chance to

answer. To avoid confusion of the teams to be answered when one or more team presses the

buzzer almost simultaneously, buzzer circuits are used.

Instead of just showing who pressed the buzzer using some LED or electric bulb, if

has some visual effects, audio effects and different options that makes the show entice. So

our approach is to make this possible which includes all the features. This project makes

the show attractive and easy to operate. This Quiz buzzer is built with the view of making

the game show priority less.

This project uses PC parallel port to input user's response from the switches

placed in the participant's table. Response of the teams can be projected on to a screen.

Number of all the teams will be displayed in the screen in order of the response.

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Chapter: 2

COMPONENT DESCRIPTION

2.1 Introduction

When a beginner to electronics first looks at a circuit board full of components

he/she is often overwhelmed by the diversity of do-dads. An electronic circuit is made up

of electronic component. Electronic components are classified as active or passive.

Passive component is one that contributes no power gain (amplification) to a circuit

or system. It has no control action and does not require any input other than a signal to

perform its function. Examples are resistors, capacitors, inductors.

Active components are those that are capable of controlling voltages or currents and

can create a switching action in the circuit. Examples are transistors, diodes, etc.

2.2 IC 7805 Voltage Regulator

It is very easy to get stabilized voltage for ICs by using a three terminal voltage

regulator.The power supply voltage for a car is +12V - +14V. At this voltage, some ICs can

not operate directly except for the car component ICs.

In this case, a three