HI - TECH RESISTORS PVT. LTD.Office : Buty Compound, Mount Road Extension, Nagpur-440 001 (INDIA)Tel : +91-712-2531134, 2533269 | Fax : (91-712) 2528334, 2556351.e-mail : info@htr-india.com (India Sales) | sales@htr-india.com (International Sales) www.htr-india.com

2015

PROD

UCT

CATA

LOGU

E

WIRE WOUND RESISTORS

SILICONE / CEMENT COATED RESISTORS 2-3 Fusible ResistoRs

SyMMETRy RESISTORS 3

CERAMIC ENCASED 4-5 Fusible ResistoRs

LOW Ohm / CURRENT SENSE ShUNT RESISTORS

CERAMIC ENCASED 6

OPEN FRAME 7

ELECTRON BEAM WELDED 8-9

SURfaCE mOUNT (SmD) RESISTORS 10

aUTOmOTIvE RESISTIvE DEvICES 11

CUSTOmISED aUTOmOTIvE RESISTIvE DEvICES (hvaC applications) 12

CUSTOmISED RESISTIvE DEvICES (Industrial applications) 13

CERTIfICaTION : ISO/TS 16949 : 2009 14

DISTRIbUTORS - INDIa 15

DISTRIbUTORS - WORLDWIDE 16-17

appLICaTION / DESIgN NOTES ON SELECTION Of WIRE WOUND RESISTORS 18-19

hTR RESISTOR fINDER (mObILE app & DESkTOp) 20-21

I N D E X

Detailed datasheets in PDF format for all HTR product series available in the ‘PRODUCT’ section of www.htr-india.com

1

WIRE WOUND RESISTORSSilicone / cement coated

WIRE WOUND RESISTORSSilicone / cement coated

SYmmETRY RESISTORS

hTapower rating : 0.75W to 12WResistance range : R01 to 100KTolerances available : 1% - 10% applications : industrial, telecommunication and consumer electronics.features : • ULapprovedflameretardantcoating• Non-inductivetypeavailable• ImpulseresistorsasperIEC61000-4-5•Industrialgrade-JSS/IECsizes.

hIapower rating : 0.5W to 20WResistance range : R01 to 120KTolerances available : 1% - 10%applications :•Industrial,telecommunicationand consumer electronics. features: • ULapprovedflameretardantcoating•IndustrialGrade-MILsizes• Non-inductivetypeavailable.• ImpulseresistorsasperIEC61000-4-5

vhIapower rating : 0.5W to 20WResistance range : R01 to 120KTolerances available : 1% - 10%applications : industrial, telecommunication and consumer electronics.features : • ULapprovedflameretardantcoating.• Non-inductivetypeavailable.• ImpulseresistorsasperIEC61000-4-5.• CoppercladsteelwireterminationsforreducedtemperatureonPCB.

fRSpower rating : 1W to 5WResistance range : 10R to 100R*Tolerance available : 1% - 10% applications : consumer, telecommunication and industrial electronics. features : • UL1412approved.• Safetyfusingat220/240V.• Tailormadefusingoptionsavailable.

Note * higher resistance values available. please enquire - info@htr-india.com

hfW power rating : 1W to 5WResistance range : 10R to 100R*Tolerance available : 1% - 10% applications : consumer, telecommunication and industrial electronics. features : • UL1412approved.• Safetyfusingat110/120V.

hfa power Rating : 1W to 10WResistance range : R10 to 51KTolerances available : 5% - 10% applications : Lowcostsolutionforconsumerelectronics.features :• Fiberglasscore.•ULapprovedflameretardantcoating.

haapower rating : 1W to 5WResistance range : R01 to 12KTolerances available : 1% - 10%applications : Miniaturesizesforautomotivesector.features : • ULapprovedflameretardantcoating• Industrialgrade• Non-inductivetypeavailable• ImpulseresistorsasperIEC61000-4-5

hIppower Rating : 3W to 10WResistance range : R01 to 90KTolerances available : 1% -10%applications : commercial and industrial electronics.features :•Ceramiccore.•PCBpluggablestyle.•ULapprovedflameretardantcoating.

hfp power rating : 2.5W to 8WResistance range :R10to56KTolerances available : 5% - 10% applications : commercial & industrial electonics.features : • FiberGlasscore.• PCBpluggablestylewithdifferent terminationsandstandoffheightsavailable.• ULapprovedflameretardantcoating.

hIRpower Rating : 10W to 500WResistance range : R22 to 100KTolerances available : 5% - 10%applications :•Highpowerdissipation&impulsehandlingcapability.•Loadbankresistors.

• Highvoltagebleederresistorinpowersupplies.features : •ULapprovedflameretardantcoating.• RadialterminalsforAmp187& Amp250connectorsavailable.• Choiceofanti-ruststainlesssteelterminations.

hSR power Rating : 8.25W, 11W & 20WResistance range : 10K to 120KTolerances available : 1% -10%applications : •Capacitorcharginganddischargingresistors.features :• Wirewoundsymmetryresistors.•ULapprovedflameretardantcoating.•Stainlesssteelterminalsfordirectmountingoncapacitors.

RSRpower Rating :40Wto500WResistance range : R05 to 18RTolerances available : 5% - 10% applications : • Highpowerdissipation&impulse handlingcapability.• Highvoltagebleederresistorinpowersupplies.• Loadbankresistors.features : •Edgewoundresistivestripforreducedsurface temperature. • Highdissipation&verylowohmic valuesavailable.• ULapprovedflameretardantcoating.• RadialterminalsforAmp187& Amp250connectorsavailable.• Choiceofanti-ruststainlesssteelterminations.

hSRC power rating : 11W, 20W & 25WResistance range : 10K to 110KTolerance available : 1% - 10% applications : • Capacitorcharging&dischargingresistors.features :•Wirewoundsymmetryresistors.• Ceramicencasedresistorsforgreaterheat dissipation.•Stainlesssteelterminalsfor directmountingoncapacitors.• Customisedsolutionsavailableupto40W.

2 3

fuΩ

fuΩ

WIRE WOUND RESISTORSceRamic encaSed

hCapower rating : 1W to 20WResistance range :R05to56KTolerance available : 1% - 10%applications : industrial and consumer electronics. features: • Fibreglassandceramiccoreavailable.•Ceramicencasedforhighdegreeof insulationandlowsurfacetemperature.• Impulsetypesavailable.•Noninductivetypeavailable.

hCvWithbracketpower rating : 7W to 20WResistance range :R05to56KTolerance available : 1% - 10%applications : industrial & consumer electronics. features : •Highstabilityverticalmountingbracketavailable.• Fibreglassandceramiccoreavailable.• Ceramicencasedforhighdegreeof insulationandlowsurfacetemperature.• Impulsetypesavailable.•Noninductivetypeavailable.

hCWpower rating : 1W to 20WResistance range :R05to56KTolerance available : 1% - 10%applications : industrial and consumer electronics. features :•Ceramiccore.• Ceramicencasedforhighdegreeof insulationandlowsurfacetemperature.• Impulsetypesavailable.• Noninductivetypeavailable.• Coppercladsteelwireterminationsforreduced temperatureonPCB.• LowTCRoptionsavailable.

fRC power rating : 1W to 3W Resistance range : 10R to 750R Tolerance available : 3% - 10% applications : industrial & consumer electronics. features : •Safetyfusingat110/120V&220/240V.•Tailormadefusingoptionsavailable.•Fibreglassandceramiccoreavailable.•Ceramicencasedforhighdegreeofinsulationandlowsurfacetemperature.

hEa power rating : 1W to 17WResistance range : R025 to 82KTolerance available : 1% - 10%applications : industrial and consumer electronics.features : •Fibreglassandceramiccoreavailable.•Ceramicencasedforhighdegreeof insulation&lowsurfacetemperature.• Impulsetypesavailable.•Noninductivetypeavailable.

WIRE WOUND RESISTORSceRamic encaSed

hSva/hSvaUpower rating : 4Wto17WResistance range : R04to82KTolerance available : 1% - 10%applications : • Bothaxialandspacesaving verticalmountingresistors.• Consumerandindustrialapplications.features : •Choiceoffibreglassorceramiccore.•DualpurposemountinginHSVAUseriesisan usefulinventoryreducerforbroadline distributor.

hSv power rating :4Wto17W Resistance range :R04to82KTolerance available : 1% - 10%applications : • Spacesaving,verticalmountingresistors.•Consumerandindustrialapplications.features : •Choiceoffibreglassorceramiccore.•Choiceofmountingpillarsforadditionalstability.•Noninductivetypeavailable.

hCppower rating : 3W to 20W Resistance range :R10to56KTolerance available : 5% & 10% applications : commercial and industrial electronics. features : • Fibreglassandceramiccoreavailable.• Ceramicencasedforhighpowerdissipation.• PCBpluggablestylewithdifferent terminationsandstandoffheightsavailable.

hCL power rating :10Wto40WResistance range :R10to68KTolerance available : 5% & 10% applications : commercial and industrial electronics.features : •Fibreglass&ceramiccoreavailable.•Ceramicencasedforhighpowerdissipation.•RadialterminationsforAmp187&Amp250connectorsavailable.

•Availablewithmountingbracketwhichalsoservesasheatsink.

hmv power rating : 2.5W to 15W Resistance range :R04to36KTolerance available : 1% - 10% applications : industrial and consumer electronics. features : •Flatverticalmountingtype•Ceramicandfibreglasscoreavailable.• Ceramiclegsforgreaterstability alsoactasheatsink.•Impulsetypesavailable.•Noninductivetypesavailable.•PCBspacesavingresistor.

hmW power rating : 5W & 9WResistance range : R18 to 18KTolerance available : 1 % - 10% applications : commercial and industrial electronics.features : • Flatverticalmountingtype• Ceramicandfibreglasscoreavailable.• Impulsetypesavailable.• Noninductivetypesavailable.• PCBspacesavingresistor.

4 5

fuΩ

LOW Ohm/CURRENT SENSE ShUNT RESISTORSCERAMIC ENCASED

bRSlimType,MetalPlate/Preformedresistancestrippower rating : 2W to 10W Resistance range : R01 to 1R2Tolerance available : 3% - 10%applications :•Reducesswitchingdistortionathighfrequency.•Audioamplifier.features: •PCBpluggablewithoption ofvariouspitchandstandoffheights.• Negligibleinductance.•Twinstyleavailable.

hmvL AlloyRibbonElement/FlatVerticalMountingpower rating : 2.5W to 15WResistance range :R004toR20Tolerance available : 0.5% - 10%applications :•Currentsensing.• Industrialandconsumerelectronics.features : • Flatverticalmountingtype.• Negligibleinductance.• Ceramiclegsforgreaterstability alsoactasheatsink.• PCBspacesavingresistor.

RL power rating : 0.5W to 10WResistance range : R0015 to R80Tolerance available : 0.5% - 10%Applications:•Currentsensinginapplicationswhichincludeswitchingandlinearpowersupplies,instrumentsandpoweramplifiers.features : •Alloyribbonelementincylindricalceramicbody.•Superioralternativetoreplacemoulded device of identical size. •Negligibleinductance.•Highlythermalefficientpowertosizeratio.•LowTCR.

hEaLpower rating : 2.5W to 12WResistance range : R0025 to R20Tolerance available : 0.5% - 10%applications : • Currentsensingforindustrialand powerconditioningapplications.features : •Alloyribbonelementinsquareprofileceramictube.• Ceramicencasedforgreaterheat dissipationandthermalstability.•LowTCR.•Negligibleinductance.

hCaLpower rating : 1W to 20WResistance range : R002 to R20Tolerance available : 0.5% - 10% applications : • Currentsensingforindustrialandpower conditioningapplications.features :•Alloyribbonelement• Ceramicencasedforgreaterheat dissipationandthermalstability.•LowTCR.• Negligibleinductance.

LOW Ohm/CURRENT SENSE RESISTORSOPEN FRAME

Oapower rating : 1W to 3WResistance range : R003 to R10Tolerance available : 1% to 10%applications :Usageinswitching,linearpowersupplies,instruments,regulatorsandothermoderncurrentsensingcircuits.features : •Openframeaxialtype.•Negligibleinductance.•LowTCR.

Oppower rating : 0.5W to 5W Resistance range : R0015 to R10Tolerance available : 1% to 10%applications : Usageinswitching,linearpowersupplies,instruments,regulatorsandothermoderncurrentsensingcircuits.features : •OpenframePCBmountingradialtype.•Negligibleinductance.•LowTCR.

hEWpower rating : 1W to 5W Resistance range : R003 to R10Tolerance available : 1% to 10%applications : Usageinswitching,linearpowersupplies,instruments,regulatorsandothermoderncurrentsensingcircuits.features : •OpenframePCBmountingradialtype.•EdgeweldingforreducedPCBfootprint.•Negligibleinductance.•VerylowTCRavailable.

OfSCpower rating : 5W & 10WResistance range : For5W-R00012toR002,For10W-R0004toR003Tolerance available : 1% to 10%applications : Highlyaccuratecurrentsensingapplicationsinautomotive&industrialelectronics.features : •Fourterminalsforhighlyaccuratecurrentsensingapplications.•ULapprovedflameretardantcoating.•Increasedleaddiameterforhighcurrenthandlingcapability.

Of power rating : 1W to 10WResistance range : R001 to R10Tolerance available : 1% to 10%applications : Usageinswitching,linearpowersupplies,instruments,regulatorsandothermoderncurrentsensingcircuits.features :•OpenframePCBmountingradialtype.•Monolithicconstructionforsuperiorstability.•Negligibleinductance.•VerylowTCRavailable

6 7

LOW Ohm / CURRENT SENSE RESISTORSELECTRON BEAM WELDED

hEE power rating :4Wto10WResistance range : R0002 to R002Tolerances available :±1%(0.5%andothertoleranceavailableonrequest)applications: •Accuratecurrentsensingforpowerhybridapplications•Suitableforweldingonbusbars• Highcurrentapplicationsforautomotivemarket• Frequencyconvertors•PowerModulesfeatures:•10WconstantpowerpossibleinR0002•Capableofcarryingcurrentupto225amp(R0002)oncontinuousbasis•Sturdycopperconnectors

• Excellentlongtermstability•Maximumsoldertemperatureupto350°Cfor30seconds.

hRE power rating :3W,4Wand5WResistance range : R0002 to R003Tolerances available : ± 1% (0.5% and othertoleranceavailableonrequest)applications: • Currentsensorforpowerhybridapplications• Highcurrentapplicationsforautomotivemarket• Frequencyconvertors•Powermodulesfeatures:•5WconstantpowerpossibleinR0002• Constantcurrentcarryingcapabilityupto160amp(R0002)•Sturdycopperconnectors

• Maximumsoldertemperature upto350°Cfor30seconds.

hhEpower rating : 5WResistance range : R0003 to R002Tolerances available :±1%(0.5%andothertoleranceavailableonrequest)applications : • Powertoolsduetonatureofphysicalconstruction• Highcurrentapplicationsfortheautomotivesector• Frequencyconvertors•Powermodulesfeatures : • 5WconstantpowerpossibleinR0003• Constantcurrentcarryingcapabilityupto 120amp(R0003)•Sturdycopperconnectors• Excellentlongtermstability.

hbEpower rating : 2W to 5WResistance range : R0005 to R005 Tolerances available :±1%(0.5%andothertoleranceavailableonrequest)applications: •Currentsensingforpowerhybridapplications•Automotiveapplicationsthatrequirehigh currentcapability•Frequencyconvertors•Powermodulesfeatures:•5WconstantpowerinR0005•4terminalconnectionsforexceptionally accuratemeasurement•Excellentlongterm stabilityduetonatureofconstruction.

hSEpower rating : 2W to 5W Resistance range : R0002 to R005 Tolerances available :±1%(0.5%andothertoleranceavailableonrequest)applications: •Accuratecurrentsensingforpowerhybrid applications•Automotiveapplicationsthat requirehighcurrentcapability•Frequencyconvertors•Powermodulesfeatures:•5Wconstantpower• Capableofcarryingcurrentupto160amp(R0002) oncontinuousbasis•Sturdycopperconnectors•Excellentlongtermstability.

LOW Ohm / CURRENT SENSE RESISTORSELECTRON BEAM WELDED

hEbpower rating :36WResistance range : R0001, R000125, R000218 R000250Tolerances available : ±5%(Availableupto±1%)applications: •CurrentsensorforEBM(ElectronicBatteryManagement)inmotorcars,trucks,forklifts,hybrid&electricvehicles.•Currentsensinginbusbars•Currentsensinginweldingequipments.features:•Upto15Wpermanentpowerinfreeair.•Continuouscurrentloadupto350A(0.1mΩ)• Highpulsepowerrating.• Max.fasteningtorque10Nm.

hOSpower rating : , 2W, 3W & 5WResistance range : R001 to R05Tolerances available : ±5%, ±3%, ±2%, ±1%applications: • CurrentsensorforPowerhybridapplications.• Intheautomotivesectorforhighcurrentapplications.•WherereducedtemperatureisrequiredonthePCB.

features :• ReducedPCBheatingduetoopenairflowdesign.• Flexiblenatureofterminationdesignforthermalexpansion.

hTEpower rating : 1W, 1.5W, 2W & 3WResistance range : R0001 to R01Tolerances available : ± 1% (0.5% and othertoleranceavailableonrequest)applications: • SensorofcurrentforPowerhybridapplications.• Automotivesectorforhighcurrentapplications.• Frequencyconvertor/Powermodules.features :• Excellentlongtermstability.• IdealformountingonDCB/IMSsubstrates.• Hightemperatureapplicationduetonature ofdesign.

8 9

SURfaCE mOUNT (SmD) RESISTORS

hIaSpower rating : 1W to 5WResistance range : R01 to 22KTolerances available : 1% - 10%applications :Fillsthegapformelfandsurfacemountresistorsinapplicationswhicharetoosevereforfilmresistors.features :•WirewoundwithmultipleSMDmountingconfigurations.•ULapprovedflameretardantcoating.•Noninductivetypesavailable.• ImpulseresistorsasperIEC61000-4-5.• 1Wand2W–MELFtype.• Tape&reelpackingforpick&placemachine.

hCaS/hCaLSpower rating : 2W & 3WResistance range :R001to5K6Tolerances available : 1% - 10%features : • WireWoundandAlloyRibbonelementoptions.• Ceramicencasedforgreaterheatdissipation &thermalstability.• Packagesize2W-4527,3W-6927.• Tapeandreelpackingforpick&placemachine.•Fusibletypeavailable.•Noninductivetypeavailable.• ImpulseresistorsasperIEC61000-4-5

hSvaS/hSvaLS power rating :4W&5WResistance range :R003to16KTolerances available : 1% - 10%features : • Wirewoundandalloyribbonelementoptions.• Ceramicencasedforgreaterheat dissipationandthermalstability.• Fusibletypeavailable.•Noninductivetypeavailable.• ImpulseresistorsasperIEC61000-4-5.

RLSpower rating : 1.5W to 5WResistance range : R0015 to R39Tolerances available : 1% - 10%applications : Currentsensinginapplicationswhichincludeswitchingandlinearpowersupplies,instrumentsandpoweramplifiers.features : •Alloyribbonelementincylindricalceramicbody• Superioralternativetoreplacemouldeddevice ofidenticalsize.•Negligibleinductance•Highlythermalefficientpowertosizeratio.•Anyresistancevaluepossiblewithin resistancerangegiven•LowTCR.

aUTOmOTIvE RESISTIvE DEvICES

Noise suppressor resistor. please refer haNS series in www.htr-india.com

for electronic braking and steering applications.

for power window applications.

Customised resistive devices for engine cooling systems.

10 11

CUSTOmISED aUTOmOTIvE RESISTIvE DEvICESHVAC APPLICATIONS

Coil type resistor for hvaC application.

Ceramic type resistors for hvaC application.

for windpower applications.

Ressistor fitted with cables for bimetallic switch

for power tools hTR can customise resistive devices for applications in various industries. Currently devices are being supplied to a large number of customers accross the industrial, automotive & consumer electronics sector. please enquire - info@htr-india.com

CUSTOmISED RESISTIvE DEvICESINDUSTRIAL APPLICATIONS

12 13

DELhI aREa Vam ElectronicsShop No. 1 & 2, 1690, Sunder Bhawan, Bhagirath Palace, Delhi - 110 006Tel : (011) 23868159. Fax : (011) 23868459e-mail : vam.electronics@yahoo.co.in | enquiry@vamelectronics.com

gUJaRaTElectrodeal202, 203, Fatehsagar Complex, Opp. Convent School,Fatehganj, Vadodara - 390 002.Tel : (0265) 3013099, 2793344. Fax : (0265) 2786677e-mail : respond@electrodeal.com sanjayvelani@electrodeal.com

mahaRaShTRaElectromark Technologies12A, Hanuman Terrace Building,1st Floor, Behind Bombay Biscuits,Tara Temple Lane, Grant Road, Mumbai - 400 007Tel : (022) 23820454 / 455 / 456. e-mail : mahavir@electromarkindia.com

Stockist : Ramesh ElectronicsNew Hanuman Building, Shop No. 8, 16, Shyamrao Vithal Marg, Lamington Road, (P.O. Kiln Lane),Mumbai - 400 007Tel : (022) 2388 5701 / 2387 5720Fax : (022) 2385 0711 / 2385 1624e-mail : rameshelectronics9@yahoo.co.in

Multitek Electro Devices167, Above Apeksha Palace, Pune-Saswad Road,Phursungi Fata, Pune - 412 308Tel / Fax : (020) 26860032. Cell : 09923391582e-mail : shahkumar@vsnl.net | multitekdevices@gmail.com

kERaLaRoni Electronics# 40/5884 C & D, AVS Building, M. G. Road, Ernakulam, Kochi - 682 035.Tel : (0484) 2355029, 2369926. Fax : (0484) 2352928.e-mail : roni@sify.com | roy@ronielectronics.com

TamILNaDUElektronika Sales Private Ltd.16, Narsingpuram Street, Mount Road, Chennai - 600 002Tel : (044) 2858-7165/2858-7765. Fax : (044) 2841 9833e-mail : info@elektronikasales.com

WEST bENgaLIndian Electronics6, Madan Street, Kolkata - 700 072. Tel : (P) (033) 22127548 (F) (033) 22126385(M) 09831232412.e-mail: indianelec1974@gmail.comwasimul2006@yahoo.co.in National Electronics Corporation 3, Chandni Approach, 1st Floor, Room No - 2 & 3, Kolkata - 700 072. Tel : (033) 2212 4066 | Telefax : (033) 2212 4062(M) 09831003907.e-mail : necorpn@yahoo.comnec_cal_haque@vsnl.net;

kaRNaTakaSwift Electrocomp Solutions (P) Ltd.# 681/99, 6th Main Road, Vijayanagar,Bengaluru - 560 040Tel : +9180-23406770 / 23406774(M) : +91-9886017544e-mail : sales@swiftelectrocomp.in vishwanath@swiftelectrocomp.in

DISTRIbUTORS-INDIa

CERTIfICaTION : ISO/TS 16949 : 2009

14 15

USa IBS Electronics, Inc.3506-W, Lake Centre Drive, Santa Ana, CA 92704-6985 USATel : + 1 714 513 5343, +1 714 751 6633e-mail : sales@ibselectronics.com

SOUTh afRICaHi-Q Electronics Pty Ltd., Syfin House, 2nd floor, Fairway Close, Ni - City / Parow, 7463, Cape Town, South Africa.Tel : + 27 21 595 1307e-mail : sales@hi-q.co.za

JOHANNESBURG AREAHi-Q Electronics Pty Ltd.,Bartlett Lake Office Park, Unit 8, Cnr. Trichardt & Leith Road, Bartlett, Boksburg, South Africa. Tel : + 27 11 894 8083e-mail : sales@hi-q.co.za

UNITED kINgDOmEurocap International Ltd.138, High Street, Cheshunt, Herts, EN8 0AP, England.Tel : + 44 1992 625407e-mail : eurocap@dial.pipex.com

VTM (UK) Ltd.Irvin House, Icknield Way, Letchworth Garden City Hertfordshire, SG6 1EF, England.Tel : + 44 1462 473820e-mail : sales@vtm.co.uk

Distributed Micro Technology Ltd.The Old Bakery, 265 Yorktown Road, College Town, Sandhurst Berkshire, GU 47 0QA, UK.Tel : + 44 1276 33391e-mail : sales@dmtl.co.uk | info@dmtl.co.uk

NEThERLaNDSHeynen BVP.O. Box 10, NL-6590 AA Gennep The Netherlands Tel : + 31 485 550937e-mail : heynen@heynen.com

gERmaNY Weltron Elektronik GmbHSommerauer Str. 11, D - 91555 Feuchtwangen, Germany.Tel : + 49 9852 6727 – 12e-mail : info@weltron.de

WDI AGIndustriestrasse 25A Industriezentrum,D-22880 Wedel (Holstein), Germany.Tel : + 49 4103 1800 152e-mail : sales@wdi.ag

SWITZERLaND Vibratec AGIndustries trasse 21, CH-5507, Mellingen, Switzerland.Tel : +41 56 481 77 77e-mail : info@vibratec.ch

SpaINAldinet GroupPol. Ind. Jose Ma Korta Parcela, A6, Nave 220750 Zumaia, Gipuzkoa, Spain. Tel : + 34 943 805 420e-mail : aldinet@aldinet.com

UkRaINEIntegral Ltd.28, Tekstylna Street, Ternopil, Ukraine - 46010Tel: +380352 261955e-mail: 123@integral.te.ua

ISRaELTrust Electronics Ltd.43, Haatzmaut Way, St. Yehud, P.O. Box : 2800, Yehud 56302, Israel. TEL : + 97 23 6322566e-mail : dov@trust-electronics.combenny@trust-electronics.com

ITaLY MOS SRL Via San Martino, 120834 Nova Milanese (MZ)MI, Italy - 1Tel : + 39 0362 364615e-mail : Acquisti@mossrl.com

aUSTRaLIaArrow Electronics14 Nicole Close, Bayswater - Victoria - 3153, Australia Tel : +613 97374900e-mail : sales.anz@arrowasia.com

phILIppINESIBS Electronics IncUnit 308, ALPAP II Building, Trade St.Corner Investment Drive, Madrigal Business Park, Ayala-Alabang, Muntinlupacity, Philippines 1770. Tel : + 632 807 6927e-mail : salesph@ibselectronics.com

INDIa

pEOpLES REpUbLIC Of ChINaIBS Technology Shenzhen Ltd., Room 3705, 37/F, International Science and Technology Building, 3007, Shen Nan Road, Shenzhen, Cn 518033. Tel : + 86 755 8221 0037e-mail : salescn@ibselectronics.com

hONgkONg IBS Tech Int’l HK Ltd.,Unit C, 5/F, Mai On Industrial Building, 17-21, Kung Yip Street, Kawi Chung, NT, Hongkong.Tel : + 852 2947 0009e-mail : saleshk@ibselectronics.com

NEW ZEaLaNDArrow ElectronicsSuite 3, Level 1, 12-18 Moorhouse Ave,Christchurch, New Zealand Tel : +64 927 22520 / +64 213 28850 e-mail : john.gillon@ arrowasia.com sales.anz@arrowasia.com

bELgIUmHeynen NVCentrum-Zuid 3047-B-3530Houthalen, BelgiumTel : +32 (0) 11 60 0910e-mail : johan.de.ceuster@heynen.be

fINLaND Oy Nylund - Group ABNylund Group Masalantie 375, 02430 MASALA, Finland.Tel : + 358 9 2219 1400.e-mail : electronics@nylund.fi

SWEDENTS Connect ABFågelsångsvägen 20186 42 Vallentuna, Sweden.Tel : Direct : + 46 (0) 732-02 13 96e-mail : larsthelin@tsconnect.se

TURkEYCan Ticaret Ve Electronik San. Ltd. Sti.Kemankes Mah. Mumhane Cad.Ikizler Is HaniNo : 42 Kat : 3 Zip Code : 34425 Karakoy Istanbul / TurkeyTel : + 90 212 244 46 48e-mail : info@canticaret.net

aUSTRIaAEK GmbhMaxglaner Haupt str. 70, 5020 Salzburg, Austria.Tel : +43 662 830810e-mail : office@aek.at

maLaYSIaAcumen Components Sdn Bhd155, Jalan Kikik, Taman Inderawasih, 13600 Perai, Pulau Pinang, Malaysia. Tel : + 60 4 3997713e-mail : cp.ng@acumen.my

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DISTRIbUTORS- WORLDWIDE

baSICS

Simplyput,aresistorisanelectroniccomponentconnectedintoanelectricalcircuittoinsertaspecificresistance.Resistanceismeasuredinohmsandasperohmslaw,thecurrentthroughtheresistorwillbedirectlyproportionaltothevoltageacrossitandinverselyproportionaltotheresistance.Asthecurrentflowsthroughtheresistor,heatisproducedwhichmakesthetemperatureoftheresistortoriseabovetheambienttemperature.

Nowwhether a particular resistor can be used in a specific electrical circuit is its ability to dissipate the heat generatedwithout physicaldeteriorationandwithinthetemperaturelimitsofthatparticularcircuit.

Resistorsareratedtodissipateagivenwattagewithoutexceedingthedeclared“hot spot” temperature.Thisislargelydeterminedbythesizeandmaterialsusedintheconstructionoftheresistorandthisiscalled“free air Watt Rating” or “full Rating” or “maximum power Rating”.

Insomecasestheconditionsactuallyencountereddeviatefromthestandardconditionsandaffectthetemperaturerisewhichdetermineswhetherthatparticularresistorcanbeusedornotinaparticularapplication.

SELECTION pROCESS – Stepwise guide

1. Decide the resistance value required ThefollowingformulaederivedfromOhmslawcanbeusedforthispurpose– R=V/IorI=V/RorV=IxRwhere, (Risresistanceinohms,VisvoltageinvoltsandIiscurrentinAmperes)

2. Decide the watts (power) to be dissipated by the resistor W=I²xRorW=VxIorW=V²/Rwhere, (WisPowerRating/Wattageinwatts,IiscurrentinAmperes,RisresistanceinohmsandVisVoltageinvolts.)

Note: Whilstthepowerratinginwattscanbetheoreticallydeterminedasabove,anoteofcautionisnowintroduced–Itisimportantthattheactualcurrentthatwillbedrawnisusedinthedeterminationofthepowerrating/wattageoftheresistor.Smallincreasesincurrentorvoltagee.g.20%translateinto44%increaseinthepowerrating/wattagerequiredtodissipatetheincreasedcurrent/voltagewithintemperatureriselimitations.Atthispointitisalsoworthmentioningthatthedesignershouldalsomakeallowanceforthemaximumpossiblelinevoltage.

3. Decide the correct physical size (“watt size”) based on the following parameters – watts, volts, temperature that can be permitted in the particular circuit and mounting consideration.

Thewattageratingofaresistorasestablishedunderspecifiedstandardconditions isdefinedas“free air Watt Rating” (maximum power Rating).

Thefollowingmethodisbroadlyusedtodetermine “free air Watt Rating” basedonthemethodsfollowedby“NationalElectricalManufacturersAssociation”–USA(NEMA),“UnderwritersLaboratoriesInc.”(UL)andUSMIL–R26–USMilitarySpecificationforwirewoundresistors.

InUSMIL–R26,therearemainly2broadcharacteristicsofresistortypes–characteristic‘V’andcharacteristic‘U’.Characteristic‘V’resistorsarerequirednottoexceedamaximumoperatingtemperatureof350°C,whichcorrespondstoamaximumtemperatureriseof325°Catambienttemperature25°C.

Characteristic‘U’resistorsarerequirednottoexceedamaximumoperatingtemperatureof275°C,whichcorrespondstoamaximumtemperatureriseof250°Cwithambienttemperature25°C.Thetemperatureisnormallymeasuredonthebodyoftheresistor,suspendedinfreestillairspacewithunrestrictedcirculationofair.

Whencurrentpassesthrougharesistor,heatisgeneratedandthetemperaturestabilizeswhenthesumofheatloss(byterminationconduction,radiationandconvection)equalstheheatinputrate(createdbypassingcurrentproportionaltowattage).

Byruleofthumb,thelargertheresistor,hencegreatertheareaforheatdissipation,thelowerthetemperaturerise.Havingsaidthis,itmustbeadmittedthatcertainotherfactorssuchasthermalconductivityoftheceramiccore,typeandgaugeofresistancewireselectedandtheheat-sinkeffectofthetypeofmountingallinfluencetheselectionofaresistortobeconsideredhaving“acceptableservicelife”.

Furtherconsiderationmustbegivenincasetheresistorwillbeoperatedinelevatedambienttemperatureshigherthan25°Cor30°C,thepowerratingmustbederatedasperthederatingcurveprovidedwitheachHTRseriesdatasheet..

appLICaTION / DESIgN NOTES ON SELECTION Of WIRE WOUND RESISTORS

appLICaTION / DESIgN NOTES ON SELECTION Of WIRE WOUND RESISTORS

absolute temperature can be arrived at after adding the prevalent ambient temperature at time of test to the temperature rise figures provided above.

These figures merely serve as a guide to a design engineer and must be verified in actual practical conditions by the design engineer before selection and use of a particular resistor.

4. Decidetheactualresistortobeused-basedonactualpracticalconsiderations. HavingdeterminedtheWattage/FreeAirwattratingontheoreticalbasis,thedesignermustnowtakethefollowingfactorsintoaccount

whendecidingontheactualresistortobeusedintheapplication,asallthesefactorswillinfluencethetemperaturerise: a. The influence of ambient Temperature -Allthecomponentsofanelectroniccircuithavetheirownlimitationsastothemaximum

temperatureatwhichtheycanreliablyfunction. The temperature that thecomponent rises to in service is the sumof theambient temperatureplus the temperature risedue toheat

dissipatedbyeachcomponentduringoperation.Somedevicescantolerateelevatedtemperatureswhilstotherscannot. Wirewoundresistorscanoperatefairlyreliablyatreasonablyelevatedtemperatures,soinordertoensurethattheheatgeneratedbythe

resistorisminimized,thedesignermaymovetoahigherpowerratingfromthetheoreticalcalculationtominimizethetemperatureriseandminimizetheeffectsofheatingonotherdeviceswhichareheatsensitiveinthecircuit.

b. The design of the Enclosure -Thewallsoftheenclosureformathermalbarrier,preventingheatfromescapingandpreventingtheoutsideairfromenteringandprovidingcooling.Hence,duecaremustbegiventotheoptimumdesign/orientationoftheventilationopeningsoftheenclosure.

c. Spacing -Incaseduetodesignlimitations,ifheatgeneratingcomponentsarebunchedtogether,theywillshowahighertemperatureriseduetoheatreceivedbyradiationfromeachother.Thereforeitisprudentifatallpossiblethatthedesignertriestopreventbunchingofheatgeneratingcomponentsandifthisisnotpossible,movestoahigherpowerratingtominimizetemperaturerise.

d. Surges - Incertainapplicationsfore.g.typicallymotorcontrollers, theresistorsdoencountersurgeconditionswhich ifnotproperlymanagedandtakenintoaccountatthetimeofdesigningtheresistor,willleadtoresistorfailure.

a “Surge”occursoversuchashortperiodoftime,inthecaseofcapacitorcharge/discharge<1msecandinthecaseofmotorstart-up<0.5sec,thatthesubstrateplaysnoroleinheatdissipationandtheenergymustbecompletelyabsorbedbytheresistiveelementitself.Pleaserefertothesection “pulse/Surge Capability of Resistors” onourwebsiteinthedesignnotessection.

Hencesurgeconditions,ifanymustbetakenintoconsiderationatthisstagetodeterminethecorrectresistorforthatapplication. e. forced air Circulation -Incaseswheretheapparatusinwhichtheresistorismountedisheatsensitiveorforcertainreasonsresistorused

isofalowerthanoptimumwattageforthatparticularapplication,forcedaircirculationremovesmoreheatinashortertimethannaturalconvectionandisadvisedinthecircumstancesenumeratedabove.

f. Derating - Itisalwaysadvisablethataresistorshouldbederatedandnotoperatedatitsactualpowerratingforlongtermreliability. Suitablederatingalsocontributesgreatlytotheminimizationof“DriftUnderload”phenomenaobservedinchangeinresistancevaluewhen

aresistorisinoperation. g. higher Resistance value -Inordertoachievehigherresistancevalues,thediameteroftheresistancewirewoundonthesubstrateisa

veryfinegauge,sometimesaslittleas0.016mm,henceformaximumreliabilityitissuggestedthatthedesigneroptsforahigherpowerratingifsizeisnotaconstraintinordertoreducethetemperaturerise.

h. high frequency Circuit -Wirewoundresistorsmaybeeffectivelyusedincircuitswithfrequencyupto50KHzwhennoninductivelywoundbythe‘Aryton-Perry’methodofwinding.

Forfurtherdetailsonthissubject,pleaserefertothesection“Wire wounds and their limitations when used in a high frequency circuit” inthe“Design notes” sectionofthewebsiteunder“guide to optimum utilization & mounting of resistors”.

MaximumPowerRating TemperatureRiseon TemperatureRiseon (30°Cambient) BodyofResistor TerminationofResistor 1W 50°Cto80°C 35°C 2W 60°Cto90°C 37°C 3W 65°Cto95°C 42°C 4W 80°Cto110°C 45°C 5W 100°Cto130°C 45°C 6W 105°Cto135°C 46°C 7W 125°Cto155°C 50°C 10W 140°Cto170°C 50°C 15W 155°Cto185°C 52°C

Forthedesignengineer’sgeneralguidance,wegivebelowthetemperaturerisethat isgenerallyobservedonsiliconcoatedaxialresistors(ambienttemperatureof30°C)atMaximumPowerRating/FreeAirRating.

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hTR RESISTOR fINDER (mObILE app & DESkTOp)

1. Find resistor by parameter: Thesearchforanappropriateresistorisfacilitatedbychoiceofresistortype,mounttype,therequiredtolerancegradeandthepackagingtypeinsubsequentscreens.

Oncetheparametersareselectedonsubsequentscreens,therequiredresistortype,itsdatasheetsummaryandweblinkaredisplayedonthescreen.

Thesubsequentscreenspromptsforselectionofaresistorseriesforwhichthereplacementis needed.

TheequivalentHTRseries,it’sdatasheetsummaryandweblinkappearimmediatelythereafter.

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Categorizedonthebasisofcountries,itgivesyouoptionsofallcountrieswhereHTRdistributorsarelocated.Uponselection,itpresentsalistofdistributorsinthatcountry.

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2. Find a replacement resistor:

3. Distributor Network:

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