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V I C H A R A C T E R I ST I CS OF I N CA N D E SC E N T L A M P &W I R E W O UN D R R E O ST / LT

A I M : a ) T o p lo t the V I c ha r a c te r ist i c s o f 2 in c an de s c e n t la m ps (60W & 100W ) w he nc o n n e c t e d i) s e par a t e ly i i) in s e r ie s & ii i) In par a l le l

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b) T o plo t t he V I c har a c te r is t ic s o f a w i r e w o u n d r he o s ta t (l in e ar r e s is ta n c e )

A PPA R A T U S :

S. N o . Na m e o f t h e

a p p a r a t u s

V o l tm e t e r

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(0 250v j(0 - 30V )(O- 1 A )(0 5A )500

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230V, 60 W

230V, I 00W

Qu a n t i ty

A m r i ie t e r

Rhe o s ta t W ir e w o u n d

In c a n de s c e n t L a m p

P RJN C I P L E :

A r e s ist a n c e is l in e a r , i f i t s V - I c ha r a c t e r is t ics is a s t r ai ght l in e pas s in g thr o u gh o r ig i n

o r if it o be y s Ohm s la w.

F o r a l in e a r r e s is ta n c e,

the v a l u e o f r e s is tan c e r e m a in s c o n s ta n t

i r r e s pe c t iv e o f the v o l t nge a c r o s s o r c u r r e n t tho u gh it W i r e w o u n d r e s i s ta n c e (u s u a l ly m a d e

o f n i c k e l c hr o m i u m a l lo y ) i s a n e x a m p le o f a l in e a r r e s is ta n c e .I n t a s e o f a n in c a n d e s c e n t

l a m p (m ad e o f t u n g s t e n f i l Bm e n t ) , i8 r e s i s ta n c e i n cTe a s e s a s the c u m n t in c r e a s e s . I f a dc

v o l ta ge is s u dde n ly a pp l i e d,

the in i t ia l c u r r e n t m ; y be tw e l v e t i m e s i t s n o r m a l o pe r a t in gc u r r e n t . 1h is l s be c a u s e the r e s in a n c e o f a c o ld t u n gs t e n f i la m e n t is a bo u t m 2 ' h

o f the

r e s i s ta n c e a t o pe m t i n g te m p e r a t u m

PR O C E D U R E :

A ) I N C A N D E SC E N T L A M P

M a k e the c o n n e c t i o n s a s sho w n h f ig u r e (N o t e : 60W la m p is c o n n e c t e d) K e e p in g the

a u to M n s f o r m e r a t m in im u m v o l t a ge po s it io n, s w it c h On t he s u pp ly A qju s t the

a u to tr a n s t b r m e r a n d tbr d i f fe r e n t v a lu e s o f v o l t a ge, n o t e the Ain m e te r an d v o ltm e t e r r e a d in gs

R e pe a t th e p r o c e du r e by c o n n ¢c t in g i) 100W lam p in pla c e of 60W l a m p i i) 100W a n d 60Wl a m p In s e r i e s en d l i i) 100W & 60W in pam l le l P l o t V I c ha r a c t e r i s t ic s f o r e B c h c a s e in the

s a m e g r a ph.

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B ) W I RE W O UN D R E SI ST A N C E

M a ke th e c o n n e c t io n s as sho w n in f igu re K ee p in g t he

v o lta ge po s i t io n l s w i tc h o n the SUpp ly Fo r v a r io u s I rjt io

v o l tm e t e r & am m e t e r r e a d in gs P lo t V I c ha J

0 5A M C

0 8 5A

T A B U L A R A N C E

V o l tm e te r

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v o lts

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re s is ta n c e

I m i m p s>

RE SU L T

a) V I c h a m c t e r is t ic s o f 6 0

i e p a r o t e ly i i ) i n se r i e s

b ) V I c h a r a c t e r is t ic s o f W

100W i n c a n pes c e n t la m ps pl o n I L he n c o n m

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M I 00W 100W & 60W 100W & 60W

IN SERE S IN PA RA U EL

T A B U L A R C O L V M N I N C A N D E SC E NT L A M P

V o l tm e t e r \

S l N o R c : ig 6601 1 I 00 W

A m m e t e r R e a din g I

60 & 10 0 W in

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A I M : m e te r u s in g w a t tm e tc r by d i r e c t lo a d i n g

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W i r e w o u n d

n am o m et e r

I n du c t i o n

250V, 5A

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5A

PR I N C I P L E :

Jo f r e v o l u t i o n s m a d e by a n e n e r gy m e t e r i n a g i v J

e n e r gy s u pp l i e d I n t h is c o n n e c t i o n , a t e r m c a l le c

d a s t he n u m be r o f r e v o lu t i o n s m a de

in t e r v a l o f t im e is P

m e t e r c o n s t a n t is u s e d

T he v a lu e o f m e t e r

m a r k e {M m e t e r

H e r e , t h e

c u m n t a n d v o l t a g e a r e

m e t e r d is c i s m e a s u r e d

th e e n e r gy m e t e r i s a w a t t m e t e r a s

c o n s t a n t d u r i n g t lle t e s t T im e t fo r N ,

l ly

s ta n d a r d T he

o n o f t hc e n e r gy

PR O C E D U R E :

M a k e th e c o n n e c t io n s a s s ho w n in C

Pr e c a u u o n s / I n i t ia l s e t t i n g s :

i) Sw i t c h D P ST in o pe n po s i t i o n

i l) A u t o t r a n s f o r m e r in m in i m u m v o 1 s it io n

i i i) A l l th e r he o st a t s a t m a x im u !n po s i t io n

Sw i t c h o n th e s u pp ly by c lo s in g D PST s w i t c h A t ju s t t he a u t o tr a n s f o r m e r a n d m a k e the

v o l t m e t e r r e a d in g e qu a l t o r a t e d v o l t a ge (= 230V ) By v a r y in g th e r he o s ta t,

a dj u s t t h e c u r r e n t

t o a s u i t a b l e v a l u e (s n y I 5A ) N o t e do w n t he v o l tm e t e r,

am m e l e r a n d w n t tm e t e r r e a d i n g s

A ls o , n o t e t h e t im e fo r 5 r e v o l u t io n s o f t h e e n e r g y m e t e r d i s c I n c r e a s e t h c c u r r e n t a n d r e p e a t

th e a bn v e p r o c e d u r e A l t e r c o m p l e t in g t h e e x p e r i m e n t,

s w i t c h o f f t h e s u pp ly b y h r in g m g a l l

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