FA8425 [TTELEC]
Fusible Metal Film Resistors; 易熔金属膜电阻器
| 型号： | FA8425 |
| 厂家： | 
TT Electronics |
| 描述： | Fusible Metal Film Resistors |
| 文件： | 总2页 (文件大小：117K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Fusible Metal Film
Resistors
Welwyn Components
FA8025 series
• Predictable fusing characteristics
Flameproof protection
•
Electrical Data
FA8225
0.25
FA8325
0.5
FA8425
1.5
Power rating at 70˚ C
Resistance range
watts
ohms
volts
0R1 - 10k
250
0R1 - 27k
350
0R15 - 22k
500
Limiting element voltage
TCR
ppm/˚ C
%
250
250
250
Resistance tolerance
Standard values
5
E24 preferred
120
Thermal impedance
Ambient temperature range
˚ C/watt
˚ C
150
90
-55 to 155
Physical Data
Dimensions (mm) & Weight (g)
PCB
Min.
mounting
centres
bend
Type
L max
6.2
D max
2.5
f min
21
d nom
0.6
radius Wt. nom
d dia
D
FA8225
FA8325
FA8425
10.2
12.7
20.3
0.6
1.2
1.2
0.3
0.6
1.1
L
f
9.0
3.4
19.6
23.8
0.8
14.5
5.1
0.8
Construction
Marking
The metal film is deposited on a high purity ceramic rod. End
caps are force fitted and termination wires welded to the
caps. The resistive film is adjusted to the required value by a
helical cut; finally the cement protection is applied to the
resistor body and marked with indelible ink.
Resistors are colour coded with five bands. Four of the bands
are used to indicate value and tolerance, with IEC 62 colours
being used. On FA8325 and FA8425 types a fifth yellow band
denotes constant voltage fusibility.
Solvent Resistance
The body protection and marking are resistant to all normal
Terminations
Material
Solder-coated copper wire.
industrial cleaning solvents suitable for printed circuits.
Strength
The terminations meet the requirements of
IEC 68.2.21.
Flammability
The resistors will not burn or emit incandescent particles
under any condition of applied temperature or power
overload.
Solderability The terminations meet the requirements of
IEC 115-1, Clause 4.17.3.2.
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.
A subsidiary of
TT electronics plc
© 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 C· 01.07
153
Fusible Metal Film
Resistors
Welwyn Components
FA8025 series
Performance Data
Maximum
Typical
0.5
Load: 1000 hours at 70˚C
R%
R%
2
Shelf life: 12 months at room temperature
Derating from rated power at 70˚ C
Temperature rapid change
0.5
0.2
zero at 155˚ C
R%
R%
0.5
0.5
0.2
0.2
Resistance to solder heat
Predicting Fusing Time For Defined Power Input
Graphs 1 to 3.
Fusible Resistors: Typical Fusing Window
Graph 4.
Normal rated
power
Fusing:
After fusing the final resistance value will be 50 times the
initial value. See graph for explanation of fusing curves.
Min power for
guaranteed
fusing
Max fusing time
Fusing
Time
Graph 1
Graph 2
Graph 3
(secs)
Max sale
fusing
power
Min fusing time
Initial Power (watts)
Packaging
The preferred method of packaging is taped and ammo
packed, see figure 1 for critical dimensions.
Alternative packaging is available by special request.
Lead Formed resistors can also be supplied. Standard options
of Lancet, Radial and Goalpost forming are shown in Lead
Form Information section.
Figure 1
c
f1
f2
b
6
6
Body Location f1 – f2 1.4 mm
Type
FA82*
FA82/FA83
FA84
67
b
c
26
5
52
5
10
Standard Quantities Per Package
Type
FA8225
FA8325
FA8425
Ammopack
5000
2500
1000
© 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 C · 01.07
154
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