精密电阻 DEEHO MFR

general specifications

mf-0204

mf-0207

mf-0410

mf-0414

mf-0617

mf-0718

rated power

1/8w

1/4w

1/2w

1w

2w

3w

mf-0207s

mf-0410s

mf-0414s

mf-0617s

mf-0718s

mf-0925s

rated power

1/4ws

1/2ws

1ws

2ws

3ws

5ws

standard dimensions (mm)

3.5±1.0

6.5±1.0

9.0±1.0

11±1.0

15±1

17±1

body diameter (d)

1.7±1.0

2.3±1.0

3.2±1.0

4.5±1.0

5.0±0.5

6±0.5

lead length (h)±2

27±2.0

26±2.0

25±2.0

30±2.0

33±2.0

33±2.0

lead diameter (d) ± 0.05

0.40±0.05

0.48±0.05

0.52±0.05

0.72±0.05

0.72±0.05

0.72±0.05

electrical specification

0204

0207

0410

0414

0617

0718

maximum working voltage (v)

200

250

350

500

500

500

maximum overload voltage (v)

400

500

700

1000

1000

1000

resistance range (±1%(f))

0.1ω-1mω

0.1ω-1mω

0.1ω-1mω

10ω-100k

10ω-100k

10ω-100k

              (±0.5%(d))

100ω-511kω

100ω-511kω

100ω-511kω

100ω-51kω

100ω-51kω

100ω-51kω

characteristics

standard

test methods

1.

 resistance temperature coefficient

 (ppm/℃)

±100 ppm/℃

natural resistance change per temperature degree centigrade.

(ppm/℃)

r1: resistance value at reference temperature. (t1)

r2: resistance value at reference temperature.(t2)

t1: room temperature

t2: t1±100℃

2.

 dielectric

 withstanding

 voltage

 no evidence of flashover, mechanical damage or arcing or, insulation break down.

resistors shall be subjected to an approximately sinusoidal test potential (as below) 60hz applied between both terminals connected together and a  90° v-block extending beyond the end of the resistor.

resistor wattage

dc volts

1/8w  (1/4wsi)

1/4w  (1/2ws)

1/2w  1w,2w above

150

350

600

3.

 solderability

 90% covered min.

the terminal lead shall be dipped into molten solder s at 3.2 to 4.8mm from the body of resistor.the temp. and time as below:

a. 235±5℃for 2±0.5 seconds

b. 270±10℃for 2±0.5seconds

4.

 resistance to soldering

 no evidence of mechanical damage

 δr/r at ±0.5% max

the terminal of the resistor is dipped into the molten solder of 350±10℃for 3±0.5 seconds. then put the resistor in the room temperature. for min.3 hours.

5.

 humidity load life

±1% max/1000hours

resistance change after 1000 hours ( 1.5 hours on  0.5 hours off)at rated continuous working voltage in a humidity chamber controlled at 40±2℃and 90~95% relative humidity .

6.

load life

±1% max/1000hours

permanent resistance change after 1000 hours  operating at rated continuous working voltage with a duly cycle of 1.5 hours on 0.5 hours off at 70 ± 2℃ambient .

7.

 temperature cycling

±1% max with no evidence of mechanical damage

resistance change after continuous five cycles for duty cycle as specified below.

step

temperature

time

1

-30℃

30 minutes

2

+25℃

10~15 minutes

3

+85℃

30 minutes

4

+25℃

10~15 minutes

characteristics

standard

test methods

8.

 short time   overload

δr/r at±0.5% max. with no evidence of arcing burning, or charring

permanent resistance change after the application of a potential of 2.5 times rated continuous working voltage for 5 seconds at room temperature.

9.

terminal strength

no  evidence  of  mechanical damage or loosening terminals

direct load resistance to 2.5kg direct load 30±5 seconds twist test, for axial leads unit only. terminal lead shall be bent through at a right angle at a point of 6.35mm from the body edge of resistor and shall be rotated through at a right angle about the original axis of the bent terminal in alternating direction for a total 3 rotations.