Page 112 - Electrician -1st Year - TT

TYo (Power) T«t£ 1.3.33 dLô] ùRôPo× LÚj§Vp
GXdh¬μVu (Electrician) þ A¥lTûP ªu²Vp T«t£ (Basic Electrical
Practice)

ªuRûP ®§Ls Utßm TpúYß YûLVô] ªuRûPLs (Laws of
resistance and various types of resistors)

úSôdLeLs: ClTôPj§u Ø¥®p ¿eLs ùT\ úYi¥V A±Ü §\uLs
• ªuRûP ®§Lû[d á±, TX®RUô] ªuRûPl ùTôÚhLû[ (materials) Jl©ÓRp
• JÚ LPj§«u ªuRûP (resistance) Utßm ARu A[ÜLÞdÏ (dimemsions) CûP«p
Es[ ùRôPo×Lû[ ®[dÏm ãj§WjûR áßRp
• JÚ LPj§«u ªuRûP (resistance) ûV ùLôÓdLlThP ϱl× (data) (i.e A[ÜLs
ØRXõVûYL°XõÚkÕ LQd¡ÓRp.
• TpúYß YûLVô] ªuRûPLû[ ®[dÏRp.
ªuRûP ®§Ls (Laws of resistance) : JÚ
LPj§«Ûs[ ªuRûP (resistance) ¸úZÙs[
LôW¦Lû[ (factors) Nôok§Úd¡\Õ.

• JÚ LPj§«u ªuRûP (resistance) ARu
¿[j§tÏ úSo®¡Rj§p CÚdÏm.

• JÚ LPj§«u ªuRûPVô]Õ ARu
ÏßdÏ ùYhÓlTWlT[®tÏ (cross-sectional
area) G§o ®¡Rj§p (inversely proportional) ⎛ ρl ⎞
⎜
CÚdÏm. G]úY ∴R = a ⎟ ⎠
⎝
• JÚ LPj§«u ªuRûPVô]Õ, AdLPj§
ùNnVlTh¥ÚdÏm ùTôÚû[f SI AXÏ Øû\«p
Nôok§ÚdÏm.

• CÕ JÚ LPj§«p HtTÓm ùYlT
¨ûXûVl ùTôÚjÕ áP UôßTÓm.
• úUÛs[ûYL°p Cߧ LôW¦ûV
UhÓm RtNUVj§tÏ LÚRôUp, CûYL°u BLúY CûQ ªuRûP (specific resistance)«u
ùRôPo©û] CqYôß Ï±l©PXôm. AXÏ Km ÁhPo ( m)

TXYûL ªuRûPL°u ùTôÚhLû[
Jl©ÓRp (Comparison of the resistance of

C§p ‘ ’ (Rho) GuTÕ CdLPj§ ùNnVlThP different materials) : Fig 2-p £X Ød¡VUô]
ùTôÚû[ NôokR JÚ constant BÏm. úUÛm ùTôÚhL°u ªu LPjÕm RuûUûVd
CÕ Rôu CûQ ªuRûP (specific resistance) LôhÓ¡\Õ. Aû]jÕ LPj§LÞm JúW A[Ü
ApXÕ ªuRûP«u G§ol×j§\u (resistivity) ÏßdÏùYhÓ TWl× JúW A[Ü ªuRûP
G]lTÓm. (resistance) A[Üm EûPV]. ùYs° (silver )
YVWô]Õ RôªW YV¬û] ®P ¿[Uô]Õ.
G]úY JÚ ùTôÚ°u CûQ ªuRûP AúR úTôp RôªW YVûW®P AÛª²Vm
(specific resistance) GuTÕ JÚ ÁhPo
YVo £±Õ Ïû\kR[Ü ¿[Uô]Õ. £pYo
TdLØs[ L]NÕWj§Ûs[ CWiÓ G§o YVo G@Ï (steel) YVûW®PÜm 5 UPeÏ
G§o TdLeLÞd¡ûP«p CÚdÏm ªuRûP
¿[Uô]Õ.
(ApXÕ £X úYû[L°p JÚ L]NÕWjûR
L] ùNu¥ ÁhP¬Ûm ϱl©PlTPXôm) G]úY JqùYôÚ EúXôLØm úYßThP
G] YûWVßdLlTÓ¡\Õ. (Fig 1) LPjÕm RuûU (conductance ratings) EûPVûY.
Utßm AûYLs úYßThP ªuRûP ®¡Rm
(resistance ratings) EûPVûY GuTûRÙm

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