debi seminar

7/23/2019 Debi Seminar

1/17

Polygraph

Presented By:-Debi Prasad SenapatiRegd. No.-:0701230119,

Roll No-:s-07-!3, "t#Se$

%&'( D()(*)+R %&'( D()(*)+R


2/17

*+N)(N)S

'ntrodtion #at is a lie detetor/ istorial perspetie )#e polygrap# $a#ine si$ple lie detetor irit Polygrap# ea$iners &ie detetor test *onter $easres and legalities ppliations *onlsion


3/17

'N)R+D4*)'+N

Apolygraph(popularly referred to as a liedetector) is an instrument that measures

and records several physiological responsessuch as blood pressure, pulse, respirationrhythms body temperature and skinconductivity while the subject is asked and

answers a series of questions, on the theorythat false answers will produce distinctivemeasurements.


4/17

) 'S &'( D()(*)+R/ ) 'S &'( D()(*)+R/


5/17

'S)+R'*& P(RSP(*)'5(

1! invention of "esar #omboso used tomeasure changes in blood pressure for policecases

A device recording both blood$pressure andgalvanic skin response was invented in 1%&' byr. ohn A. *arsonof the +niversity of "aliforniaand rst applied in law enforcement work .

-arston remained the devices primary advocate. /n 1%0 he published a book, he *ie etector

est, wherein he documented the theory and useof the device.


6/17

)( P+&6RP 8*'N( )( P+&6RP 8*'N(

he lie detector does not measure truth$telling2 itmeasures changes in blood pressure, breath rateand perspiration rate.

most polygraph tests are administered with digitalequipment. he scrolling paper has been replacedwith sophisticated algorithms and computermonitors.


7/17


8/17

S'8P&( &'( D()(*)+R *'R*4') S'8P&( &'( D()(*)+R *'R*4')


9/17

'8P&'8(N))'+N

)#e irit diagra$ o t#e &ie Detetor is s#on aboe.'t onsists o t#ree transistors %)R1 to )R3, a apaitor%*1, to lig#ts or &(Ds %&1 ; &2, inresistane #anges #en t#ey seat %seating beaset#ey=re lying. Dry s>in #as a resistane o abot 1$illion o#$s, #ereas t#e resistane o $oist s>in isreded by a ator o ten or $ore.

Resistors R1 and R2 or$ a oltage diider. )#ey #aeresistanes o 1 000 000 o#$s %1 $ega o#$s and,bease t#eir ales are e?al, t#e oltage at t#e pperprobe ire is #al t#e battery oltage %abot @.! olts.


10/17

person #olding t#e probe ires ill #ange t#eoltage at t#e pper probe ire depending ont#eir s>in resistane. )#e s>in resistane is inparallel it# R2 and, bease it is li>ely to besi$ilar to or s$aller t#an R2, t#e oltage at t#eprobe ire ill all as s>in resistane alls.

*apaitor *1 ntions as a s$oot#ing apaitorand re$oes t#e !0A inded $ains #$ t#at is

ond on a person=s body. )R1 and R3 or$ a ber irit %alled an

e$itter-olloer. )#e oltage at t#e e$itter o)R1 ollos t#e oltage at t#e probe ire and is

no able to drie transistor )R2.

*ontinedC


11/17

)ransistors )R1 and )R2 at as a oltage o$parator.' t#e oltage at t#e base o )R2 is #ig#er t#an at t#ebase o )R3 t#en t#e green &(D %&1 ill o$e on. 't#e reerse is tre t#en t#e red &(D %&2 ill lig#t.

)o test t#e &ie Detetor #old t#e probe ires. dst5R1 ntil t#e green &(D is st on and t#e red &(D is

st o. )#is is t#e point at #i# t#e oltage at t#ebase o )R2 is st greater t#an at t#e base o )R3.

No se $oist in resistane and ases t#e oltage att#e base o )R2 to all. )#e oltage at t#e base o

)R3 is no greater and t#e red &(D o$es on.

*ontinedC


12/17

P+&6RP (E8'N(RS

3etting up the polygraph and preparing thesubject being tested

Asking questions

4roling the test subject

Analy5ing and evaluating test data


13/17

&'( D()(*)+R )(S)

Pretest Design questions In-test Post-test

wo ways that a response can be misinterpreted

False positive

False negative


14/17

PP&'*)'+NS

Use with Espionage and security clearance

Hand-held Lie detector for US ilitary

Polygraph in Popular culture


15/17

*+N*&4S'+N

4olygraph e6ams are most often

associated with criminal investigations, but

there are other instances in which they areused. 7ou may one day be subject to a

polygraph e6am before being hired for ajob8 -any government entities, and some

private$sector employers, will require orask you to undergo a polygraph e6am priorto employment.


16/17

R(F(R(N*(S

#ttp:GGen.i>ipedia.orgGi>iGPolygrap#

#ttp:GGs>epdi.o$Gpolygrap.#t$l

#ttp:GG.psy#opolygrap#.o$G

#ttp:GG.polygrap#.orgG

#ttp:GG.nap.edGopenboo>.p#p/isbnH03090"@3I9

#ttp:GGpeople.#ostor>s.o$Glie-detetor.#t$
http://en.wikipedia.org/wiki/Polygraphhttp://skepdic.com/polygrap.htmlhttp://www.psychopolygraph.com/http://www.polygraph.org/http://www.nap.edu/openbook.php?isbn=0309084369http://www.nap.edu/openbook.php?isbn=0309084369http://people.howstuffworks.com/lie-detector.htmhttp://people.howstuffworks.com/lie-detector.htmhttp://people.howstuffworks.com/lie-detector.htmhttp://people.howstuffworks.com/lie-detector.htmhttp://www.nap.edu/openbook.php?isbn=0309084369http://www.nap.edu/openbook.php?isbn=0309084369http://www.polygraph.org/http://www.psychopolygraph.com/http://skepdic.com/polygrap.htmlhttp://en.wikipedia.org/wiki/Polygraph


17/17

ny Jestions / /

)NK 6+4C..

debi seminar

Documents