Commercial Discrete
Vishay Ultronix
Commercial Discrete Wirewound Resistors
Axial and Radial Models
FEATURES
•
High precision
•
All welded construction
•
Molded thermosetting plastic bobbin
•
Wide ohmic range combined with tight tolerance
•
Excellent long-term stability
•
Inherent low temperature coefficient
•
Extremely low Thermal EMF
•
Low voltage coefficient
•
Low noise
STANDARD ELECTRICAL SPECIFICATIONS
MODELS
123A
118A
122A
102A
102AL
101A
153A
103A
135A
105A
184A
185A*
MAXIMUM
RESISTANCE VALUE
(Ohms)
111k
192k
199k
334k
334k
410k
435k
633k
750k
820k
820k
961k
968k
1.42 M
1.7 M
1.93 M
3.0 M
3.0 M
4.10 M
5.63 M
7.68 M
10 M
24 M
35 M
43 M
43 M
453k
821k
1.59 M
1.48 M
3.3 M
9.5 M
POWER RATING
@ 125
°
C
(Watts)
0.05
0.05
0.05
0.10
0.10
0.10
0.10
0.10
0.10
0.125
0.125
0.125
0.25
0.25
0.25
0.33
0.50
0.60
0.50
0.60
1.00
1.00
1.25
1.50
1.75
2.00
0.125
0.125
0.25
0.25
0.50
1.00
ELECTRICAL SPECIFICATIONS
Minimum Values:
0.1 ohm for
±
1% and
±
0.5%.
10 ohm for
±
0.1% and tighter.
Resistance Tolerance:
±
0.005%,
±
0.01%,
±
0.02%,
±
0.05%,
±
0.1%,
±
0.5%, and
±
1%, depending on style
and value.
Temperature Coefficient:
±
10 ppm/°C standard for 10
ohm and above. Higher T. C.’s on low ohmic values. T. C.
match to
±
1 ppm/°C. High T. C.’s up
to + 6000 ppm/°C are available.
Standard temperature range:
– 10°C to + 80°C.
Working temperature range:
– 60°C to + 145°C.
CONSTRUCTION
All Welded Construction:
The combination of all welded
construction and compatible materials provide the most
reliable means of interconnects possible.
Butt Weld of Tab to Lead:
A tab material of
800 ohm alloy (the same as the resistance wire)
is butt welded to the lead and molded deep into
the resistor bobbin. This design parameter assures the least
possible D. C. transients due to thermal EMF.
Bobbin Design:
The ratio of the height of the Pi wall to the
width of the Pi and to the diameter of the bobbin mandrel
are critical to the basic stability of a wirewound resistor.
These parameters are optimized for each wire size, wattage
size and range of resistor values.
Encapsulation Material:
Both the bobbin and the final
encapsulation material are thermosetting alkyd polyester.
The resulting resistor is virtually a homogeneous mass with
an identical coefficient of expansion which is unaffected by
the most violent of temperature cycling. All types are
unaffected by application of solvents.
Lead Materials:
The standard lead material is hot solder
dipped copper (C5N). Other available materials are bare
nickel (N1N) and gold plated nickel (N2N).
AXIAL
202A
204A
203A
205A*
207A*
308A
210A*
307A
310A
505A
510A*
515A*
517A
520A*
101P
102P
RADIAL
203PC
203PA
305PA
505PA
* Available in hermetically sealed. See page 7.
Document Number: 69101
Revision 06-Oct-00
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