FM Datasheet, PDF (1/2 Pages) Welwyn Components Limited – Fusible Metal Film Resistors

Fusible Metal Film
Resistors
FM Series
• Predictable fusing characteristics
• ^{Flameproof protection}
Welwyn Components
Electrical Data
Power rating at 70˚ C
Resistance range
Limiting element voltage
TCR
Resistance tolerance
Standard values
Thermal impedance
Ambient temperature range
watts
ohms
volts
ppm/˚ C
%
˚ C/watt
˚C
FM¹/4
0.25
0R1 - 10K
250
150
Physical Data
Dimensions (mm) & Weight (g)
Type
FM¹/4
FM¹/2
FM1
L max
6.2
9.0
12.5
D max
2.35
3.4
4.2
f min
21.0
19.6
17.8
d nom
0.6
0.8
0.8
PCB
mounting
centres
10.2
12.7
18.4
Min.
bend
radius
0.6
1.2
1.2
Wt. nom
0.3
0.6
0.9
FM¹/2
0.5
0R1 - 27K
350
250
5
E24 preferred
120
-55 to 155
d
D
L
FM1
1.0
0R2 - 1K5
350
100
f
Construction
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
special helical cut; finally the cement protection is applied to
the resistor body and marked with indelible ink.
Terminations
Material
Solder-coated copper wire.
Strength
The terminations meet the requirements of
IEC 68.2.21.
Solderability The terminations meet the requirements of
IEC 115-1, Clause 4.17.3.2.
Marking
Resistors are colour coded with five bands. Four of the bands
are used to indicate value and tolerance, with IEC 62 colours
being used. A fifth yellow band denotes constant voltage
fusibility.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuits.
Flammability
The resistors will not burn or emit incandescent particles
under any condition of applied temperature or power
overload.
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.
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
Telephone: [phone] · Facsimile: [phone] · Email: [e-mail] · Website: www.welwyn-tt.com
164
A subsidiary of
TT electronics plc
Issue CB · 031.027