Cov hlau tsis kam yog cov hlau uas siv los ua cov hluav taws xob resistors (uas siv los tswj cov hluav taws xob tam sim no hauv lub voj voog). Nws zoo dua yog tias cov hlau siv muaj qhov tsis kam siab, vim tias cov hlau luv dua tuaj yeem siv tau. Hauv ntau qhov xwm txheej, qhov ruaj khov ntawm cov resistor yog qhov tseem ceeb tshaj plaws, thiab yog li cov hlau kub coefficient ntawm resistivity thiab corrosion tsis kam ua lub luag haujlwm tseem ceeb hauv kev xaiv cov khoom siv.

Thaum siv cov hlau tsis kam rau cov khoom cua sov (hauv cov cua sov hluav taws xob, cov tshuab ci mov, thiab lwm yam), kev tiv taus siab thiab kev tiv taus oxidation yog qhov tseem ceeb.

Qee zaum cov xov hlau tiv taus raug rwb thaiv los ntawm cov hmoov av ceramic thiab sheathed rau hauv ib lub raj ntawm lwm cov hlau alloy. Cov khoom cua sov no yog siv rau hauv qhov cub hluav taws xob thiab cov cua sov dej, thiab hauv cov qauv tshwj xeeb rau cov qhov cub.
Cov hlua hlau yog ob peb txoj hlua hlau uas ntswj ua ib lub helix tsim ua ib txoj hlua sib xyaw, hauv ib qho qauv hu ua "laid rope". Cov hlua hlau loj dua muaj ntau txoj hlua ntawm cov hlua uas tau muab tso rau hauv ib qho qauv hu ua "xov hlautso".

Cov hlau rau cov hlua hlau feem ntau yog ua los ntawm cov hlau tsis yog hlau nrog cov ntsiab lus carbon ntawm 0.4 txog 0.95%. Lub zog siab heev ntawm cov hlua hlau ua rau cov hlua hlau txhawb nqa cov zog tensile loj thiab khiav hla cov sheaves nrog cov kab uas me me.

Hauv cov xov hlau uas hu ua cross lay strands, cov xov hlau ntawm cov txheej sib txawv hla ib leeg. Hauv cov xov hlau uas feem ntau siv parallel lay strands, qhov ntev ntawm tag nrho cov xov hlau txheej yog sib npaug thiab cov xov hlau ntawm ob txheej superimposed yog sib luag, ua rau muaj kev sib cuag linear. Cov xov hlau ntawm txheej sab nraud yog txhawb nqa los ntawm ob lub xov hlau ntawm txheej sab hauv. Cov xov hlau no yog cov neeg zej zog raws tag nrho qhov ntev ntawm cov xov hlau. Cov xov hlau sib luag yog ua nyob rau hauv ib qho kev ua haujlwm. Lub zog ntawm cov xov hlau nrog hom xov hlau no yeej ib txwm loj dua li ntawm cov (tsis tshua siv) nrog cov xov hlau sib luag. Cov xov hlau sib luag nrog ob txheej xov hlau muaj kev tsim kho Filler, Seale lossis Warrington.

Hauv paus ntsiab lus, cov hlua khi yog cov hlua puag ncig vim lawv muaj cov txheej hlau sib dhos ua ke uas muab tso rau saum ib qho chaw nrog tsawg kawg ib txheej hlau raug muab tso rau hauv qhov kev taw qhia rov qab rau ntawm txheej sab nraud. Cov hlua khi tuaj yeem ntsuas qhov ntev kom lawv tsis tig uas txhais tau tias thaum muaj kev ntxhov siab, lub zog ntawm txoj hlua yuav luag xoom. Cov hlua khi qhib tsuas yog muaj cov hlua puag ncig xwb. Cov hlua khi ib nrab thiab cov hlua khi tag nrho yeej ib txwm muaj qhov chaw ua los ntawm cov hlua puag ncig. Cov hlua khi xauv muaj ib lossis ntau txheej sab nraud ntawm cov hlua profile. Lawv muaj qhov zoo uas lawv txoj kev tsim kho tiv thaiv kev nkag mus ntawm cov av thiab dej mus rau ntau qhov thiab nws kuj tiv thaiv lawv ntawm kev poob ntawm cov roj nplua nyeem. Tsis tas li ntawd, lawv muaj ib qho zoo ntxiv vim tias qhov kawg ntawm cov hlua sab nraud tawg tsis tuaj yeem tawm ntawm txoj hlua yog tias nws muaj qhov ntev tsim nyog.
Cov xov hlau uas muaj hlua khi yog ua los ntawm ntau cov xov hlau me me uas muab khi ua ke los yog qhwv ua ke los ua ib lub xov hlau loj dua. Cov xov hlau uas muaj hlua khi yooj ywm dua li cov xov hlau khov kho uas muaj tib thaj chaw seem. Cov xov hlau uas muaj hlua khi yog siv thaum xav tau kev tiv taus hlau ntau dua. Cov xwm txheej zoo li no suav nrog kev sib txuas ntawm cov laug cam hauv cov khoom siv ntau lub rooj tsavxwm luam tawm, qhov twg qhov ruaj khov ntawm cov xov hlau khov kho yuav tsim kev ntxhov siab ntau dhau vim yog kev txav mus los thaum sib dhos lossis kev pabcuam; Cov xov hlau AC rau cov khoom siv; cov twj paj nruagxov hlaus; cov xov hlau nas khoos phis tawj; cov xov hlau hluav taws xob vuam; cov xov hlau tswj hwm txuas cov khoom siv tshuab txav mus los; cov xov hlau tshuab khawb av; cov xov hlau tshuab tom qab; thiab ntau lwm yam.