RES-HPW Datasheet, PDF (1/2 Pages) Ohmite Mfg. Co. – Low voltage coefficient

HPW Series
High Precision Welded Axial and Radial
F e at u r e s
• 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
Series Specifications


Max.
Type
Ohms
118A
192k
102A
334k
101A
410k
153A
435k
103A
633k
105A
820k
184A
820k
185A*
961k
202A
968k
203A
1.7 M
205A*
1.93 M
207A*
3.0 M
308A
3.0 M
210A*
4.10 M
307A
5.63 M
310A
7.68 M
505A
10 M
510A*
24 M
515A*
35 M
517A
43 M
520A*
43 M
203PA
1.48 M
305PA
3.3 M
*Available in hermetically sealed
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
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
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.
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.
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).
124
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