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  MOSQUITO REPELLER

The theory behind this circuit is quite simple and amazinly e!!ecti"e# $hen!emale mosquitoes %the ones that bite you& are prenant they pre!er to staya'ay !rom male mosquitoes and search !or !ood %your blood&# The circuitreproduces the ultrasonic noise that a male produces( this in turn repels

the !emale mosquitoes

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)IR)UIT *I+,R+M

In the circuit diagram of an ultrasonic mosquito repeller.The circuit is based on the theorythat insects like mosquito can be repelled by using sound frequencies in the ultrasonic

(above 20KH! range.The circuit is nothing but a "## I$ $%&' 0) *ired as an

oscillator *orking at 22KH.+ complementary symmetry amplifier consisting of four

transistor is used to amplify the sound.The pieo buer converts the output of amplifier

to ultrasonic sound that can be heard by the insects.

COMPONENTS:-

1) Zero PCB *1

2) Transformer 12-0-12 *1

3) Diodes 4007 *4

4) Electrolytic Caacitor 2200!"#2$% *1

$) &e'!lator (C 712 *1

) &esistor 470o+m *2

7) (C CD4047 *1

) %aria,le &esistor 10o+m

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.) Caacitor 4/7n" *1

10)Transistor 100 *2

11)Transistor 100 *2

12)Caacitor 22!"#1% *1

13)Pieo B!er *1

  )O-STRU)TIO-

PO$ER SUPPL.T+ere are many tyes of oer s!ly/ ost are desi'ned to con5ert +i'+ 5olta'e 6C mains electricity to a s!ita,le lo 5olta'e s!ly for electronics circ!its and ot+erde5ices/ 6 oer s!ly can ,y ,roen don into a series of ,locs# eac+ of +ic+erforms a artic!lar f!nction/

Eac+ of t+e ,locs is descri,ed in more detail ,elo8• Transformer  - stes don +i'+ 5olta'e 6C mains to lo 5olta'e 6C/• &ectifier  - con5erts 6C to DC# ,!t t+e DC o!t!t is 5aryin'/• moot+in' - smoot+s t+e DC from 5aryin' 'reatly to a small rile/• &e'!lator  - eliminates rile ,y settin' DC o!t!t to a fi9ed 5olta'e/

Poer s!lies made from t+ese ,locs are descri,ed ,elo it+ a circ!it dia'ramand a 'ra+ of t+eir o!t!t8

• Transformer only • Transformer : &ectifier  • Transformer : &ectifier : caacitor 

• Transformer : &ectifier : caacitor : &e'!lator• Transformer only

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T+e lo' "oltae +) o!t!t is s!ita,le for lams# +eaters and secial 6C motors/ (t isnot s!ita,le for electronic circ!its !nless t+ey incl!de a rectifier and a smoot+in'caacitor/

Transformer : &ectifier 

T+e "aryin *) o!t!t is s!ita,le for lams# +eaters and standard motors/ (t is not s!ita,le for electronic circ!its !nless t+ey incl!de a smoot+in' caacitor/

Transformer : rectifier : smoot+in'

T+e smooth *)  o!t!t +as a small rile/ (t is s!ita,le for most electronic circ!it

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Trans!ormar/recti!ier/capacitor/reulator 

 

T+e reulated *) o!t!t is 5ery smoot+ it+ no rile/ (t iss!ita,le for all electronic circ!its/

Trans!ormer 

Transformers con5ert 6C electricity from one 5olta'e toanot+er it+ little loss of oer/ Transformers or onlyit+ 6C and t+is is one of t+e reasons +y mainselectricity is 6C/

te-! transformers increase 5olta'e# ste-dontransformers red!ce 5olta'e/ ost oer s!lies !se a

ste-don transformer to red!ce t+e dan'ero!sly +i'+mains 5olta'e ;230% in <) to a safer lo 5olta'e/T+ein!t coil is called t+e primary and t+e o!t!t coil is called t+e secondary/ T+ere isno electrical connection ,eteen t+e to coils# instead t+ey are lined ,y analternatin' ma'netic field created in t+e soft-iron core of t+e transformer/ T+e tolines in t+e middle of t+e circ!it sym,ol reresent t+e core/

Transformers aste 5ery little oer so t+e oer o!t is ;almost) e=!al to t+e oerin/ >ote t+at as 5olta'e is steed don c!rrent is steed !/T+e ratio of t+en!m,er of t!rns on eac+ coil# called t+e turns ratio# determines t+e ratio of t+e5olta'es/ 6 ste-don transformer +as a lar'e n!m,er of t!rns on its rimary ;in!t)

coil +ic+ is connected to t+e +i'+ 5olta'e mains s!ly# and a small n!m,er oft!rns on its secondary ;o!t!t) coil to 'i5e a lo o!t!t 5olta'e/

Transformer circ!it sym,ol

 

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  t!rns ratio ?%

 ?>

  andoer o!t ? oer in

%s >s %s @ (s ? % @ (

% ? rimary ;in!t) 5olta'e> ? n!m,er of t!rns on rimary coil( ? rimary ;in!t) c!rrent

 

%s ? secondary ;o!t!t) 5olta'e>s ? n!m,er of t!rns on secondary coil(s ? secondary ;o!t!t) c!rrent

0ride Recti!ier 

 6 ,rid'e rectifier can ,e made !sin' fo!r indi5id!al diodes# ,!t it is also a5aila,le insecial aca'es containin' t+e fo!r diodes re=!ired/ (t is called a f!ll-a5e rectifier

,eca!se it !ses all t+e 6C a5e ;,ot+ ositi5e and ne'ati5e sections)/ 1/4% is !sed! in t+e ,rid'e rectifier ,eca!se eac+ diode !ses 0/7% +en cond!ctin' and t+ereare alays to diodes cond!ctin'# as s+on in t+e dia'ram ,elo/ Brid'e rectifiersare rated ,y t+e ma9im!m c!rrent t+ey can ass and t+e ma9im!m re5erse 5olta'et+ey can it+stand ;t+is m!st ,e at least t+ree times t+e s!ly & 5olta'e so t+erectifier can it+stand t+e ea 5olta'es)/ Please see t+e Diodes a'e for moredetails# incl!din' ict!res of ,rid'e rectifiers/

0ride recti!ier  6lternate airs of diodes cond!ct#

c+an'in' o5er t+e connections so t+e alternatin'

directions of 

 6C are con5erted to t+e one direction of DC/

Output1 !ull2'a"e "aryin *);!sin' all t+e 6C a5e)

)apacitor 

moot+in' is erformed ,y a lar'e 5al!e electrolytic caacitor  connected across t+eDC s!ly to act as a reser5oir# s!lyin' c!rrent to t+e o!t!t +en t+e 5aryin' DC5olta'e from t+e rectifier is fallin'/ T+e dia'ram s+os t+e !nsmoot+ed 5aryin' DC

;dotted line) and t+e smoot+ed DC ;solid line)/ T+e caacitor c+ar'es =!icly neart+e ea of t+e 5aryin' DC# and t+en disc+ar'es as it s!lies c!rrent to t+e o!t!t/

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>ote t+at smoot+in' si'nificantly increases t+e a5era'e DC 5olta'e to almost t+eea 5al!e ;1/4 @ & 5al!e)/ "or e9amle % & 6C is rectified to f!ll a5e DCof a,o!t 4/% & ;1/4% is lost in t+e ,rid'e rectifier)# it+ smoot+in' t+is increasesto almost t+e ea 5al!e 'i5in' 1/4 @ 4/ ? /4% smoot+ DC/

moot+in' is not erfect d!e to t+e caacitor 5olta'e fallin' a little as it disc+ar'es#'i5in' a small ripple "oltae/ "or many circ!its a rile +ic+ is 10A of t+e s!ly5olta'e is satisfactory and t+e e=!ation ,elo 'i5es t+e re=!ired 5al!e for t+esmoot+in' caacitor/ 6 lar'er caacitor ill 'i5e less rile/ T+e caacitor 5al!e m!st,e do!,led +en smoot+in' +alf-a5e DC/

moot+in' caacitor for 10A rile# C ?$ @ (o

%s @ f 

C ? smoot+in' caacitance in farads ;")(o ? o!t!t c!rrent from t+e s!ly in ams ;6)%s ? s!ly 5olta'e in 5olts ;%)# t+is is t+e ea 5al!e of t+e !nsmoot+ed DCf ? fre=!ency of t+e 6C s!ly in ;)# +ert $0

Reulator 

 

%olta'e re'!lator (Cs are a5aila,le it+ fi9ed ;tyically $# 12 and 1$%) or 5aria,leo!t!t 5olta'es/ T+ey are also rated ,y t+e ma9im!m c!rrent t+ey can ass/>e'ati5e 5olta'e re'!lators are a5aila,le# mainly for !se in d!al s!lies/ ostre'!lators incl!de some a!tomatic rotection from e9cessi5e c!rrent ;o5erloadrotection) and o5er+eatin' ;t+ermal rotection)/

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any of t+e fi9ed 5olta'e re'!lator (Cs +a5e 3 leads and loo lie oer transistors#s!c+ as t+e 712 :12% 16 re'!lator s+on on t+e ri'+t/ T+ey incl!de a +ole forattac+in' a +eatsin if necessary/

  I) )*3435

,eneral *escriptionT+e CD4047B is caa,le of oeratin' in eit+er t+e monosta,le or asta,le mode/ (tre=!ires an e9ternal caacitor ;,eteen ins 1 and 3) and an e9ternal resistor ;,eteen ins 2 and 3) to determine t+e o!t!t !lse idt+ in t+e monosta,le mode#and t+e o!t!t fre=!ency in t+e asta,le mode/6sta,le oeration is ena,led ,y a +i'+le5el on t+e asta,le in!t or lo le5el on t+e asta,le in!t/ T+e o!t!t fre=!ency;at $0A d!ty cycle) at and o!t!ts is determined ,y t+e timin' comonents/ 6fre=!ency tice t+at of is a5aila,le at t+e scillator !t!tF a $0A d!ty cycle isnot '!aranteed/onosta,le oeration is o,tained +en t+e de5ice is tri''ered

,y G-to-(H transition at+

tri''er in!t or (H-to-G transition at−

tri''erin!t/ T+e de5ice can ,e retri''ered ,y alyin' a sim!ltaneo!s G-to-(H

transition to ,ot+ t+e + tri''er and retri''er in!ts/6 +i'+ le5el on &eset in!t resets

t+e o!t!ts to G# to (H/6eatures

• Gide s!ly 5olta'e ran'e8 3/0% to 1$%

•  i'+ noise imm!nity8 0/4$ %DD ;ty/)

• o oer TT comati,ility8 "an o!t of 2 dri5in' 74 or 1 dri5in' 74

SPE)I+L 6E+TURES

• o oer cons!mtion8 secial C oscillator  Confi'!ration

•onosta,le ;one-s+ot) or asta,le ;free-r!nnin') eration

• Tr!e and comlemented ,!ffered o!t!ts

• nly one e9ternal & and C re=!ired

MO-OST+0LE MULTI7I0R+TOR 6E+TURES

• Positi5e- or ne'ati5e-ed'e tri''er 

• !t!t !lse idt+ indeendent of tri''er !lse d!ration

• &etri''era,le otion for !lse idt+ e9ansion

• on' !lse idt+s ossi,le !sin' small &C comonents ,y means of e9ternal

co!nter ro5ision

• "ast reco5ery time essentially indeendent of !lse Gidt+

• P!lse-idt+ acc!racy maintained at d!ty cycles aroac+in' 100A+ST+0LE MULTI7I0R+TOR 6E+TURES

• "ree-r!nnin' or 'ata,le oeratin' modes

• $0A d!ty cycle

• scillator o!t!t a5aila,le

• Hood asta,le fre=!ency sta,ility

• Tyical= ±2A + 0/03AI°C J 100

• "re=!ency= ±0/$A + 0/01$AI°C J 10 de5iation ;circ!its trimmed to

fre=!ency %DD = 10%±10A)

+pplications

• "re=!ency discriminators

• Timin' circ!its

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• Time-delay alications

• En5eloe detection

• "re=!ency m!ltilication

• "re=!ency di5ision

)onnection *iaram

 6unction Table-ote 81 E9ternal resistor ,eteen terminals 2 and 3/ E9ternal caacitor ,eteenterminals 1 and 3/

Terminal )onnections Output Pulse Typical Output6unction To 7** To 7SS Input Pulse 6rom Period or 

To Pulse $idth1+stable Multi"ibrator 

"ree-&!nnin' 4# $# # 14 7# # .# 12 10# 11# 13 t6;10# 11) = 4/40 &C

Tr!e Hatin' 4# # 14 7# # .# 12 $ 10# 11# 13 t6 ;13) = 2/20 &C

Comlement Hatin' # 14 $# 7# # .# 12 4 10# 11# 13Monostable Multi"ibrator Positi5e-Ed'e Tri''er 4# 14 $# # 7# .# 12 10# 11

>e'ati5e-Ed'e Tri''er 4# # 14 $# 7# .# 12 10# 11 t ;10# 11) = 2/4 &C

&etri''era,le 4# 14 $# # 7# . # 12 10# 11E9ternal Co!ntdon ;>ote 1) 14 $# # 7# # .# 12

0loc9 *iaram

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Loic *iaram

Physical *imensions

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7ariable Resistors

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)onstruction

%aria,le resistors consist of a resistance trac9 it+connections at ,ot+ ends and a 'iper  +ic+ mo5es alon' t+etrac as yo! t!rn t+e sindle/ T+e trac may ,e made from

car,on# cermet ;ceramic and metal mi9t!re) or a coil of ire;for lo resistances)/ T+e trac is !s!ally rotary ,!t strai'+ttrac 5ersions# !s!ally called sliders# are also a5aila,le/

%aria,le resistors may ,e !sed as a r+eostat it+ t'oconnections ;t+e ier and K!st one end of t+e trac) or as a otentiometer  it+ allthree connections in !se/ iniat!re 5ersions called resets are made for settin' !circ!its +ic+ ill not re=!ire f!rt+er adK!stment/

%aria,le resistors are often called potentiometers in ,oos and catalo'!es/ T+eyare secified ,y t+eir ma9im!m resistance# linear or lo'arit+mic trac# and t+eir

+ysical sie/ T+e standard sindle diameter is mm/

T+e resistance and tye of trac are mared on t+e ,ody8  3:5 LI- means 4/7 linear trac/  8M LO, means 1 lo'arit+mic trac/

ome 5aria,le resistors are desi'ned to ,e mo!nted directly on t+e circ!it ,oard# ,!tmost are for mo!ntin' t+ro!'+ a +ole drilled in t+e case containin' t+e circ!it it+stranded ire connectin' t+eir terminals to t+e circ!it ,oard/Linear %LI-& and Loarithmic %LO,& trac9s

Linear %LI-& trac means t+at t+e resistance c+an'es at a constant rate as yo!mo5e t+e ier/ T+is is t+e standard arran'ement and yo! s+o!ld ass!me t+is tyeis re=!ired if a roKect does not secify t+e tye of trac/ Presets alays +a5e lineartracs/

Loarithmic %LO,& trac means t+at t+e resistance c+an'es sloly at one end oft+e trac and raidly at t+e ot+er end# so +alfay alon' t+e trac is not +alf t+e totalresistanceL T+is arran'ement is !sed for 5ol!me ;lo!dness) controls ,eca!se t+e+!man ear +as a lo'arit+mic resonse to lo!dness so fine control ;slo c+an'e) isre=!ired at lo 5ol!mes and coarser control ;raid c+an'e) at +i'+ 5ol!mes/ (t is

imortant to connect t+e ends of t+e trac t+e correct ay ro!nd# if yo! find t+att!rnin' t+e sindle increases t+e 5ol!me raidly folloed ,y little f!rt+er c+an'e yo!s+o!ld sa t+e connections to t+e ends of t+e trac/

Rheostat

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T+is is t+e simlest ay of !sin' a 5aria,le resistor/ T'oterminals are !sed8 one connected to an end of t+etrac# t+e ot+er to t+e mo5ea,le ier/ T!rnin' t+esindle c+an'es t+e resistance ,eteen t+e to terminalsfrom ero ! to t+e ma9im!m resistance/

&+eostats are often !sed to "ary current# for e9amle to control t+e ,ri'+tness of alam or t+e rate at +ic+ a caacitor c+ar'es/

Potentiometer 

%aria,le resistors !sed as otentiometers +a5e all threeterminals connected/

T+is arran'ement is normally !sed to "ary "oltae# for e9amle to set t+e sitc+in'oint of a circ!it it+ a sensor# or control t+e 5ol!me ;lo!dness) in an amlifier

circ!it/ (f t+e terminals at t+e ends of t+e trac are connected across t+e oers!ly t+en t+e ier terminal ill ro5ide a 5olta'e +ic+ can ,e 5aried from ero! to t+e ma9im!m of t+e s!ly/

Presets

T+ese are miniat!re 5ersions of t+e standard 5aria,leresistor/ T+ey are desi'ned to ,e mo!nted directly ontot+e circ!it ,oard and adK!sted only +en t+e circ!it is,!ilt/ "or e9amle to set t+e fre=!ency of an alarm tone

or t+e sensiti5ity of a li'+t-sensiti5e circ!it/ 6 smallscredri5er or similar tool is re=!ired to adK!st resets/

Presets are m!c+ c+eaer t+an standard 5aria,le resistors so t+ey are sometimes!sed in roKects +ere a standard 5aria,le resistor o!ld normally ,e !sed/

Multiturn presets are !sed +ere 5ery recise adK!stments m!st ,e made/ T+escre m!st ,e t!rned many times ;10:) to mo5e t+e slider from one end of t+e tracto t+e ot+er# 'i5in' 5ery fine control/

Preset;oen style) Presets;closed style) !ltit!rn reset

TR+-SISTOR

&+eostat ym,ol 

Potentiometer ym,ol 

Preset ym,ol 

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 Transistors can be regarded as a type of s*itch, as can many electronic components. They

are used in a variety of circuits and you *ill find that it is rare that a circuit built in a school

Technology -epartment does not contain at least one transistor. They are central to

electronics and there are t*o main types /"/ and "/". %ost circuits tend to use /"/.

There are hundreds of transistors *hich *ork at different voltages but all of them fall into

these t*o categories.

Transistors are manufactured in different shapes but they have three leads(legs!.

The  BASE   *hich is the lead responsible for activating the transistor.The COLLECTOR 

*hich is the positive lead.The  EMITTER  *hich is the negative lead.The diagram belo*

sho*s the symbol of an  NPN  transistor. They are not al*ays set out as sho*n in the diagrams

to the left and right, although the 1tab on the type sho*n to the left is usually ne3t to the

1emitter.

PIEZO BUZZER

 A Piezo buzzer is made from two conductors that are separated by Piezocrystals.When a voltage is applied to these crystals, they push on oneconductor and pull on the other. The result of this push and pull is a soundwave. These buzzers can be used for many things, like signaling when aperiod of time is up or making a sound when a particular button has beenpushed. The process can also be reversed to use as a guitar pickup. Whena sound wave is passed, they create an electric signal that is passed

on to an audio amplier

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CONTINENTAL INSTITUTE

  OF

  ENGINEERING & TECHNOLOGY

 

PROJECT REPORT

 

SUBMITTED TO SUBMITTED BY

  PRADEEP Kr. YADAV