Resistors
METAL FILM RESISTORS
The WMF series Metal Film Resistors are manufactured using the latest Magnetron Vacuum Sputtering System. This ensures a very stable resistive medium having a very low temperature coefficient. The resistors are insulated with layers of light blue lacquer. The WMF series offer a wide range of power rating (0.125W, 0.25W, 0.40W, 0.50W, 1W, 2W & 3W), tolerances (0.1%, 0.5%, 1%, 2%, 5%) and TCRs (15, 25,50 & 100 ppm/ºC)

MPN

SPECIFICATION

Type No.

WMF 12 / WMF 25 M WMF 25 / WMF 40 / WMF 50 M WMF 50 / WMF 100 M WMF 100 / WMF 200 M WMF 200 / WMF 300 M

Rated Power at 70'C

0.125 W / 0.25 W 0.25 W / 0.40 W / 0.50 W 0.50 W / 1 W 1 W / 2 W 2 W / 3 W

Resistance Range (E24 series)

0.1 E to 10 Meg 0.1 E to 10 Meg 0.1 E to 10 Meg 0.1 E to 10 Meg 0.1 E to 10 Meg

Maximum working voltage at 70'c at normal air pressure

200V 250V 350V 500V 500V

Maximum Over Load Voltage

400V 500V 700V 1000V 1000V

Operating Temperature Range

-40 ºC to + 150ºC -40 ºC to + 150ºC -40 ºC to + 150ºC -40 ºC to + 150ºC -40 ºC to + 150ºC

Dielectric Strength

400V No break down
Δ R max. ± 0.5%
500V No break down
Δ R max. ± 0.5%
700V No break down
Δ R max. ± 0.5%
1000V No break down
Δ R max. ± 0.5%
1000V No break down
Δ R max. ± 0.5%

TCR RANGE

Tolerance Range

0.1% & 0.5% 1% 2% 5%

TCR(PPW/ºC)

15/25 25/50/100 50/100 100

CHARACTERISTICS

Terminal Strength

no damage
Δ R max. ± 0.5%

Resistance to soldering heat (350ºC)

Δ R max. ± 1%

Solderability

good tinnin
no damage

Temperature Cycling
-55 ºC to ± 155 ºC

Δ R max. ± 0.25%

Life 1000 hours at Rated Power

Δ R max. ± 1%

Short time overload

Δ R max. ± 0.5%

Resistance to solvents

no damage
E 24 Series
10 11 12 13 15 16 18 20 22 24 27 30
33 36 39 43 47 51 56 62 68 75 82 91
E 96 Series
100 102 105 107 110 113 115 118 121 124 127 130 133 137 140 143
147 150 154 158 162 165 169 174 178 182 187 191 196 200 205 210
215 221 226 232 237 243 249 255 261 267 274 280 287 294 301 309
316 324 332 340 348 357 365 374 383 392 402 412 422 432 442 453
464 475 487 499 511 523 536 549 562 576 590 604 619 634 649 665
681 698 715 732 750 768 787 806 825 845 866 887 909 931 953 976
DIMENSIONS (in mm)

TYPE WMF 12/WMF 25M

H = 26 ± 2 L = 3.3 ± 0.2 D = 1.7 ± 0.1 d = 0.45 ± 0.05

TYPE WMF 25/TYPE WMF 40/WMF 50M

H = 26 ± 2 L = 6.0 ± 0.4 D = 2.2 ± 0.1 d = 0.50 ± 0.05

WMF 50/WMF 100M

H = 26 ± 2 L = 9.0 ± 0.5 D = 3.2 ± 0.2 d = 0.60 ± 0.05

TYPE WMF 100/WMF 200M

H = 26 ± 2 L = 11 ± 1.0 D = 4.3 ± 0.5 d = 0.65 ± 0.05

TYPE WMF 200/WMF 300M

H = 26 ± 2 L = 15 ± 1.0 D = 5.0 ± 0.5 d = 0.75 ± 0.05
Colour lst figure 2nd figure 3rd figure Multiplier Tolerance
Black 0 0 0 1
Brown 1 1 1 10 ± 1%
Red 2 2 2 100 ± 2%
Orange 3 3 3 1,000
Yellow 4 4 4 10,000
Green 5 5 5 100,000 ± 0.5%
Blue 6 6 6 1,000,000 ± 0.25%
Violet 7 7 7 10,000,000 ± 0.1%
Gray 8 8 8
White 9 9 9
Gold 0.1 ± 5%
Silver 0.01 ± 10%