HPW Series
F e at u r e S
High Precision Welded Axial and Radial
• 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
S e r i e S S P e c i F i c at i o n S
cHaracteriSticS
Minimum Values
0.1Ω for ±1% and ±0.5%; 10Ω for ±0.1% and tighter
Resistance
±0.005%, ±0.01%, ± 0.02%, ±0.05%, ±0.1%, ±0.5%,
Tolerance
and ±1%, depending on style and value
*Available in hermetically sealed
Type
118A
102A
101A
153A
103A
105A
184A
185A*
202A
203A
205A*
207A*
308A
210A*
307A
310A
505A
510A*
515A*
517A
520A*
203PA
305PA
Max.
Ohms
192k
334k
410k
435k
633k
820k
820k
961k
968k
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
1.48 M
3.3 M
Power Rating
@125°C
(Watts)
0.05
0.10
0.10
0.10
0.10
0.125
0.125
0.125
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
0.25
0.50
Max.
Volts
150
150
300
150
300
300
200
200
400
800
800
800
800
800
1200
1200
1200
150
Butt Weld of Tab to
A tab material of 800 ohm alloy (the same as the
Terminal
resistance wire) is butt welded to the terminal and
molded deep into the resistor bobbin. This design
parameter assures the least possible DC 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.
Temperature
±10ppm/°C standard for 10Ω and above. Higher TC’s
Coefficient (TCR
on low ohmic values. TC match to ±1ppm/°C. High
TC’s upto +6000ppm/°C are available
Working tempera-
–60°C to +150°C
ture range
All Welded
The combination of all welded construction and com-
Construction
patible materials provide the most reliable means of
interconnects possible.
Encapsulation
Both the bobbin and the final encapsulation material
Material
are thermosetting alkyd polyester. The resulting resis-
tor 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.
Terminal Materials
The standard terminal material is hot solder dipped
copper (C5N).
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124
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PCB Design
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