dimensions (mm) and weight (g) type l d d 1 k weight max max max min wrm 0102 2.2 1.1 1.1 0.35 0.01 wrm 0204 3.7 1.55 1.55 0.5 0.02 wrm 0207 6.1 2.4 2.4 0.5 0.08 mini melf resistors wrm series high reliability predictable pulse handling capability tolerances down to 0.1% tcr down to 5 ppm/? general note welwyn components reserves the right to make changes in product specification without notice or liability. all information is subject to welwyn s own data and is considered accurate at time of going to print. ?welwyn components limited ?bedlington, northumberland ne22 7aa, uk telephone: +44 (0) 1670 822181 ?facsimile: +44 (0) 1670 829465 ?email: info@welwyn-tt.com ?website: www.welwyn-tt.com wrm 0102 wrm 0204 wrm 0207 power rating at 70? watts 0.2 0.25 0.4 resistance range ohms r22 ?2m21 r22 ?10m r22 ?8m2 limiting element voltage volts 150 200 250 tcr ppm/? 15, 25, 50 5, 15, 25, 50 25, 50 resistance tolerance % 0.1, 0.25, 0.5, 1.0, 2, 5 standard values e24 & e96 thermal impedance k/w 250 200 140 ambient temperature range ? -55 to +125 insulation resistance ohms >10 10 electrical data physical data issue d ?09.06 a subsidiary of tt electronics plc welwyn components l k l 1 d d 1 construction a metal film is deposited onto a high dissipation ceramic former to which tin plated teminating caps are fitted. the resistor is adjusted to value by a helical cut in the film and the body is protected by a lacquer coating. marking resistance values are colour coded with 4 or 5 bands depending on type. terminations material plated steel cap. solderability the pure tin finish produces ageing free contacts on which low melting solders can be used. dipped area shall be covered with a smooth and bright solder coating after 3 seconds immersion at 215?. solvent resistance the body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuit boards.
mini melf resistors wrm series ?welwyn components limited bedlington, northumberland ne22 7aa, uk telephone: +44 (0) 1670 822181 ?facsimile: +44 (0) 1670 829465 ?email: info@welwyn-tt.com ?website: www.welwyn-tt.com issue d ?09.06 welwyn components tcr and tolerance range * tc 10ppm & 5ppm is specified over the temperature range -10? to +85?. * resistors to be mounted on a pc-board according to iec 115-1, clause 4.27.1 performance data type tcr tolerance reference 5% 2% 1.0% 0.5% 0.25% 0.1% wrm0102 ?0ppm r22 ?r91 iro ?9r1 10r ?2.21m 47rs ?221k 100r ?221k wrm0102 ?5ppm 10r ?221k 47r5 ?221k 100r ?221k 100r ?100k wrm0102 ?5ppm 100r ?100k 100r ?100k 100r ?100k wrm0102 ?0ppm wrm0102 ?5ppm wrm0204 ?0ppm r22 ?r91 1r ?10m 10r ?475k 22r ?332k 43r ?332k wrm0204 ?5ppm 10r ?475k 10r ?475k 22r ?332k 43r ?332k wrm0204 ?5ppm 10r ?221k 22r ?221k 43r ?221k wrm0204 ?0ppm 22r ?221k 43r ?221k wrm0204 ?5ppm 100r ?100k 100r ?100k wrm0207 ?0ppm r22 ?r91 1r ?8.2m 10r ?1m wrm0207 ?5ppm 10r ?1m wrm0207 ?5ppm wrm0207 ?0ppm wrm0207 ?5ppm test results ? r/r stability class description 0.25 0.5 1.0 10 ? ?<75 ? 0.22 ? ?<10 ? 75 ? ?<100 k ? >100 k ? ?332 k ? >332 k ? ?10 m ? short time overload* 0.05% + 0.01 ? 0.1% + 0.01 ? 0.25% + 0.05 ? bending test* 0.05% + 0.01 ? 0.1% + 0.01 ? 0.25% + 0.05 ? resistance to soldering heat 0.05% + 0.01 ? 0.1% + 0.01 ? 0.25% + 0.05 ? temperature rapid change 0.05% + 0.01 ? 0.1% + 0.01 ? 0.25% + 0.05 ? endurance* load life 1000h 0.25% + 0.05 ? 0.25% + 0.05 ? 0.5% + 0.05 ? 8000 h 0.5% + 0.05 ? 0.5% + 0.05 ? 1.0% + 0.05 ? climatic sequence* 0.25% + 0.05 ? 0.5% + 0.05 ? 1.0% + 0.05 ? damp heat steady state* 0.25% + 0.05 ? 0.5% + 0.05 ? 1.0% + 0.05 ? current noise < 0.05 ?/v < 0.25 ?/v < 3 ?/v solderability dipped area shall be covered with a smooth and bright solder coating of at least 96% voltage coefficient < 0.5 . 10 6 /v voltage proof no flashover or breakdown
mini melf resistors wrm series ?welwyn components limited bedlington, northumberland ne22 7aa, uk telephone: +44 (0) 1670 822181 ?facsimile: +44 (0) 1670 829465 ?email: info@welwyn-tt.com ?website: www.welwyn-tt.com issue d ?09.06 welwyn components 100 10 1 0,1 10 s 100 s 1 ms 10 ms 100 ms 1 s 10 s pulse duration t i pulse load p max wrm 0102 wrm 0204 wrm 0207 w 100 10 1 0,1 10 s 100 s 1 ms 10 ms 100 ms 1 s 10 s pulse duration t i continuous pulse load p max wrm 0102 wrm 0204 wrm 0207 w single pulse maximum pulse load continuous pulses maximum pulse load type wrm 0204 c - 1k0 f i size tcr value (use iec62 code) tolerance (use iec62 code) packing c 50ppm/? t 10ppm/? d 25ppm/? v 5ppm/? y 15ppm/? b 0.1% d 0.5% g 2% c 0.25% f 1% j 5% 0102 3000 / reel (7? i tape 0204 3000 / reel (7?* standard 0207 1500 / reel (7? ordering procedure example: wrm0204 at 1 kilohm, 1% tolerance and 50ppm/? tcr on a reel of 3000 pieces - * high precision parts may be supplied on 1000 piece reels ?please enquire packaging the wrm 0102 and 0204 resistors are supplied reeled on 8mm blister tape. wrm 0207 resistors are supplied on 12mm blister tape. packaging complies with the requirements of iec 286-3.
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