CARBON FILM RESISTORS,FLAMEPROOF
1. Applicable Scope:
This standard specification is for use in consumer electronics, computers,
telecommunications, control instruments...etc.
2. Part Number:
It is composed by Type, Rated Wattage,Nominal Resistance, Tolerance and
Package/Terminal Form. e.g.
RD
Type
1/4W
Rated Wattage
100Ω
Nominal Resistance
J
Tolerance
T/B
Package/Terminal Form
2.1 Type :
Carbon Film Resistors are called "RD". "RDN" represents flameproof.
2.2 Rated Wattage:
Shown by "W", such as RD 1/8W(1/6W,1/4WS),1/4W(1/2WS),1/2W; RDN 1W,2W.
2.3 Nominal Resistance:
Ω,KΩ,MΩare
its unit, which be in accordance with JIS-C6409 article 6 (EIA RS-196A)
series.
2.4 Tolerance:
It is measured by Bridge-method at room temperature and expressed by a capital letter.
G＝±2% , J＝±5% ,K＝±10%.
2.5 Package/Terminal Form:
T/R＝tape & reel ; T/B＝tape in box; Nil＝Bulk ; MG form, M form, F form.
Remark : RD Series Resistors are RoHS Compliant.
3. Rated Power:
Rated power is the value of Max load voltage specified at the ambient temperature of 70℃,
and shall meet the functions of electrical and mechanical performance. When the ambient
temperature surpasses above mentioned temperature, the value declines as per following
DERATING CURVE
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CARBON FILM RESISTORS,FLAMEPROOF
3.1 Rated Voltage:
It is calculated through the following formula:
where E: rated voltage (V)
P: rated power (W)
E
=
PXR
R: nominal resistance value (Ω)
However, in case the voltage calculated exceeds the maximum load voltage, such the
maximum load voltage shall be regarded as its rated voltage, means whichever less.
4. Dimension and structure:
4.1 Dimension:
TYPE
RD 1/8W,1/6W,(1/4WS)
RD 1/4W(1/2WS)
RD 1/2W
RDN 1W
RDN 2W
D±1
1.7±0.2
2.4±0.5
3.5
4.5
5
L±1
3.7max
6.4
9
11
15
H±3
28
28
28
28
28
d±0.1
0.45
0.6
0.65
0.8
0.8
Resistance
Range
3.9Ω~4.7MΩ
3.9Ω~10MΩ
3.9Ω~10MΩ
3.9Ω~10MΩ
3.9Ω~10MΩ
Unit: mm
Max
Working
Voltage
200V
250V
350V
500V
750V
◎
Notes:1. too low or too high ohm value can be supplied only case by case.
2. Max Overload Voltage is 2 times of Max Working voltage.
3. Resistance value over 4.7MΩ (≧4.7MΩ), while RD 1/8W is
≧1MΩ,
the tolerance shall be
±10%.
4.RD 1/4W,1/2W can also supply flameproof form (RDN).
4.2 STRUCTURE:
4.2.1 Ceramic Rod:
It is made of Forsterite imported from Japan.
4.2.2 Carbon Film:
Under high vacuum and high temperature to split and oxidize the pure
carbon-hydric.
4.2.3 Terminal:
Terminal is to be firmly connected with resistors element, both electrically and
mechanically, and allow easy soldering.
4.2.4 Coating:
Coating is done by EPOXY insulating paint which is solid enough to be free from
looseness, crack and easy breakage. The paint shall be limited within 1mm of lead
wires from resistors body while the rated wattage is 2W the paint is limited within
2mm. RDN type is coated by flameproof paint which is resistant to 800℃ without
causing looseness, crack and easy breakage.
4.2.5 Marking:
Marking is made by color coding on surface.
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CARBON FILM RESISTORS,FLAMEPROOF
5. Operating Temperature Range: -55℃½155℃
6. Mechanical Performance:
6.1 Terminal tensile:
To Fix the resistor body, a static load of 1.5kgs. (1/8W & 1/4W axial form:1kg.)is to be
gradually applied into the terminal for 10 seconds without causing any looseness and
fall.
6.2 Twist withstand:
To bend the lead wire at the point of about 6mm from resistor body to 90°, then catch
the wire at 1.2
±0.4mm
apart from the bent point end and turn it (clockwise) by 360
degrees perpendicular to the resistor axis at speed of 5 seconds per turn, and do the
same counterclockwise again which constitute a whole turn. Repeat the turn 2 times
without causing any break and looseness.
7. Electrical Performance:
7.1 Resistance Temperature Coefficient:
It shall be as following:
T.C.
TYPE
1/6W , 1/8W
1/4W & OVER
0 ~ -450
≦47KΩ
≦100KΩ
0 ~ -700
51KΩ~100KΩ
110KΩ~1MΩ
0 ~ -1000
110KΩ~330KΩ
1.1MΩ~2.2MΩ
0 ~ -1300
360KΩ~1MΩ
2.4MΩ~4.7MΩ
T.C. (ppm/℃) =［(R2－R1)
÷R1½ ×［1 ÷(T2－T1)½ ×10
6
where
R1: resistance value at reference temperature
R2: resistance value at test temp.
T1: reference temp. (usu. 25℃)
T2: test temp. (about 75℃)
7.2 Temperature Cycle:
Following temp. cycles are to be made 5 times and then put at room temp. for one hour,
the resistance value change rate between pre-and-post test shall be within
±1%.
Steps
1
st
step
2
nd
step
3
rd
step
4
th
step
Temperature(℃)
-55 ± 3
Room temp.
155 ± 3
Room temp.
Time (minutes)
30
3
30
3
7.3 Short Time Over Load:
When the resistors are applied 2.5 times as much as rated voltage for 5 seconds
continuously, it shows no evidence of arc, flame...etc. Removing the voltage and place
the resistors to the normal condition for 30 minutes, the resistance value change rate
between pre-and-post test shall be within
±1%.
7.4 Insulation Character :
Resistors are located in a V-shaped metal trough. Using the DC 500V megger
instrument 2 poles to clutch either side of lead wires and metal trough, measuring the
Insulation Resistance which shall be over 10000MΩ.
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CARBON FILM RESISTORS,FLAMEPROOF
7.5 Voltage Withstanding:
Resistors are located in a V-shaped metal trough. RD: applying Max overload voltage
for one minute (RDN: applying 350V AC for one minute) and should find no physical
damage to the resistors. The resistance value change shall be within
±0.5%.
7.6 Load Life:
The resistors arrayed are sent into the 70℃ oven, applying rated voltage at the cycle
of 1.5 hours ON, 0.5 hour OFF for 1000
+48
hours in total. Then, after removing the
-0
voltage, take the resistors out of the oven and left under normal temp. for one hour
cooling. The resistance value change rate between pre-and-post test shall be within
±5%.
7.7 Moisture-proof Load Life:
The resistors arrayed are placed into a constant temp./humidity oven at the temp. of 40
±2℃
and the humidity of 90½95%, then rated power is applied for 1.5 hours and cut
off for 0.5 hour. The similar cycle will be repeated for 500
+24
hours in total (including
-0
cut-off time). Then remove the voltage, taking the resistors out of the oven and leaving
them at room temp. for one hour. The resistance value change rate between
pre-and-post test shall be within
±5%.
There also shall be no evidence of remarkable
change on appearance, and the marking shall not be illegible.
7.8 Solder-ability:
The leads with flux are dipped in a melted solder of 235±5℃ for 2 seconds, more than
95% of the circumference of the lead wires shall be covered with solder.
7.9 Resistance to Soldering Heat:
Two leads are together dipped in a melted solder of 270±5℃ for 10±1 seconds, or 350
±10℃
for 3.5±0.5 seconds, Then remove the resistors and leaving them at room temp.
for one hour. The resistance value change rate between pre-and-post test shall be
within
±1%.
7.10 Nonflammability:(only for RDN)
The resistors are applied the power of 16 times the rated wattage for 5 min. and shall
not get flame.
8.Forming:
8.1 MG Form:
Unit: mm
Wattage
1/4W(1/2WS)
1/2W
1W
2W
L±1
6.4
9
11
15
D±1
2.4±0.5
3.5
4.5
5
P
10±1
15±1.5
15±1.5
20±2
H
7±1
7±1
7±1
10±2
h±1
4.5
4.5
4.5
4.5
A±0.02 B±0.05
0.2
0.2
0.3
0.3
0.8
0.8
1
1
C±0.2
1.2
1.2
1.4
1.4
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