mf12, MF25 & mf50 series metal film resistors page 1 10/05/05 v1.0 materials and features: ? eia standard colour-coding. ? low noise and voltage coefficient. ? low temperature coefficient range. ? nichrome resistor element provides stable performance in various environments. ? multiple epoxy coating on vacuum-deposited metal film provides superior moisture protection. dimension: style power rating at 70c (w) d maximum l maximum h3 mf 12 0.125 1.85 3.5 0.45 28.0 mf 25 0.25 2.5 6.8 0.54 mf 50 0.5 3.5 10.0 +0.02 -0.05 d dimensions : millimetres general specification style dielectric withstanding voltage (v) maximum working voltage (v) maximum overload voltage (v) resistance tolerance temperature coefficient resistance range mf 12 400 200 400 1% 50ppm/c 1 ? to 1m ? mf 25 500 250 500 mf 50 700 350 700 dimensions : millimetres supplied bandoliered on tape (box = 5000 pcs. for mf12 and MF25 series) (box = 1000 pcs. for mf50 series).
mf12, MF25 & mf50 series metal film resistors page 2 10/05/05 v1.0 current noise level derating curve load life performance specification characteristics test methods limits temperature coefficient natural resistance change per temperature degree centigrade. r 2 - r 1 r 1 ( t2-t1 ) r 1 : resistance value at room temperature (t 1 ) r 2 : resistance value at room temperature plus 100c (t 2 ). within the temperature coefficient specified below maximum tcr 50ppm/c dielectric withstanding voltage resistors shall be clamped in the trough of a 90 metallic v-block and shall be tested at ac potential respectively specified in the above list for 60 +10/-0 seconds. no evidence of flashover mechanical damage, arcing or insulation break down. temperature cycling resistance change after continuous five cycles for duty cycle specified resistance change rate is (1% +0.05 ). no evidence of mechanical damage. step temperature time 1 -55c 3c 30 minutes 2 room temperature 10-15 minutes 3 +155c 3c 30 minutes 4 room temperature 10-15 minutes short-time overload permanent resistance change after the application of a potential of 2.5 times rcwv for 5 seconds. resistance change rate is (0.5% +0.05 ). no evidence of mechanical damage. pulse overload resistance change after 10,000 cycles (1 second "on", 25 seconds "off") at 4 times rcwv. resistance change rate is (1% +0.05 ). no evidence of mechanical damage. x 10 6 (ppm/ c) 100 1k 10k 100k 1m +0.8 +0.4 0 -0.4 -0.8 r/r (%) nominal resistance ( ) percent rated load (%) ambient temperature (c)
mf12, MF25 & mf50 series metal film resistors page 3 10/05/05 v1.0 characteristics test methods limits load life in humidity resistance change after 1000 hours (1.5 hours "on", 0.5 hour "off") at rcwv in a humidity test chamber controlled at 40c 2c and 90 to 95% relative humidity. resistance value r/r normal type 1.5% load life permanent resistance change after 1000 hours operating at rcwv with duty cycle of 1.5 hours "on" 0.5 hours "off" at 70c 2c ambient. resistance value r/r normal type 1.5% terminal strength direct load: resistance to a 2.5kgs direct load for 10 seconds in the direction of the longitudinal axis of the terminal leads. twist test: terminal leads shall be bent through 90 at a point of about 6mm from the body of the resistor and shall be rotated through 360 about the original axis of the bent terminal in alternating direction for a total of 3 rotations. no evidence of mechanical damage. resistance to soldering heat permanent resistance change when leads immersed to 3.2 - 4.8mm from the body in 350c 10c solder for 3 0.5 seconds. resistance change rate is (1% +0.05 ). no evidence of mechanical damage. solderability the area covered with a new, smooth, clean, shiny and continuous surface free from concentrated pinholes. test temperature of solder : 235c 5c. dwell time in solder : 3+0.5/-0 seconds. 95% coverage minimum. resistance to solvent specimens shall be immersed in a bath of trichroethane completely for 3 minutes with ultrasonic. no deterioration of protective coating and markings. rcwv = rated continuous working voltage = rated power x resistance value performance specification
mf12, MF25 & mf50 series metal film resistors page 4 10/05/05 v1.0 part number explanation: mf type 12 wattage rating 1r5 ohmic values wattage rating : 12 = 0.125w, 25 = 0.25w and 50 = 0.5w. ohmic values : where r = ohms = k = kilo ohms = k . m = mega ohms = m . and replaces the decimal point. eg : 1r5 = 1.5 . 4k5 = 4.5k . 6m8 = 6.8m . tolerance wattage range value 1% 0.125w 1r - 1m 1% 0.25w 1r - 1m 1% 0.5w 1r - 1m stocked values
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