Ultra Precision Bulk
Metal Film Resistors
4800 Series
Welwyn Components
•
BS/CECC approved
•
Tolerances down to 0.005%
•
Current noise and distortion below level
•
•
•
•
of practible measurement
Low thermal e.m.f
Ideal resistor for precision instrumentation
Use of bulk metal gives superior stability
Planar construction gives low residual
capacitance and inductance
Electrical Data
Commercial
Power Rating at 20°C
Resistance Range
Limiting element voltage
TCR (20 to 70°C)
Resistance tolerance
watts
ohms
volts
ppm/°C
4802/12/32
0.5
1R0 to 100K
200
5
4804
1
350
5
4805
1.5
500
5
See table 1 below
Notes
0R5 to 200K 33R0 to 300K
Approved BS CECC 40-302-002*
Power rating at 70°C
Resistance range
Limiting element voltage
TCR (-55 to 125°C)
watts
ohms
volts
ppm/°C
4802/12
0.25
100 to 56K
200
5
Resistance tolerance
Thermal impedance
Values
Ambient temperature range
°C
°C/watt
250
130
E24 and E96 preferred
-55 to 155
80
See table 1 below
Any value to order
All styles and products
* BS CECC 40 Style reference: 4802 BX; 4812 CX
Table 1. Resistance Range (ohms) and Tolerance (%)
Tolerance (code)
0.005 (E)
0.01 (L)
0.02 (P)
0.05 (W)
0.1 (B)
0.25 (C)
0.5 (D)
1.0 (F)
4802/12/32
200R to 100K
100R to 100K
50R to 100K
25R to 100K
10R to 100K
5R to 100K
2R to 100K
1R to 100K
4804
100R to 200K
50R to 200K
25R to 200K
10R to 200K
5R to 200K
2R to 200K
10R to 200K
0.5R to 200K
4805
65R to 300K
33R to 300K
17R to 300K
8R to 300K
3.3R to 300K
1.7R to 300K
0.6R to 300K
0.33R to 300K
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
Issue B · 03.02
© 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
186
Ultra Precision Bulk Metal
Film Resistors
4800 series
Welwyn Components
Physical Data
Dimensions (mm) & Weight (g)
Type
4802
4812
4804
4805
4832
L max
8.9
7.5
15.2
22.6
9.7
H max
10.2
8
13.2
13.2
5.4
W max
3.8
2.5
3.8
3.8
9.7
T min
30
30
30
30
30
d nom
0.6
0.6
0.6
0.6
0.6
S nom
5.1
5.1
10.2
17.8
1.5
Wt. nom
1
0.6
T
H
4802/12/04/05
L
W
d dia
S
4832
1.5
2
1.1
d
H
L
T
W
S
Construction
The resistor element is an etched bulk metal foil, bonded to
an alumina substrate. Connections to the foil are made by
copper wires welded to the foil to minimise thermal e.m.f.
Before encapsulation, the resistor element is coated with
silicone rubber to isolate the element from mechanical stress
which would adversely affect the carefully balanced
construction and result in poor resistance/temperature
characteristics.
Terminations
Material
Strength
Solderability
Solder coated copper wire
The terminations meet the requirements of
IEC 68.2.21.
The terminations meet the requirements of
IEC 115-1, Clause 4.17.3.2.
Marking
Type reference, resistance value, tolerance and date code are
legend marked. The resistance value conforms to IEC 62.
Solvent Resistance
The protection will withstand all normal industrial solvents
suitable for cleaning printed circuit boards.
Performance Data
Actual
Load at commercial rating: 1000 hours at 70°C
Dry heat: 1000 hours at 155°C
Shelf life: 12 months at room temperature
Derating from rated power at 70°C
Short term overload
Climatic category
Climatic
Long term damp heat
Temperature rapid change
Resistance to solder heat
Vibration and bump
Noise. (in a decade of frequency)
Voltage coefficient of resistance
Insulation Resistance
Inductance
Capacitance
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
µV/V
ppm/V
ohms
µH
pF
Maximum
0.05
0.05
Zero at 155°C
0.01
55/155/56
0.05
0.05
0.01
0.01
0.01
Below level of
practicable measurement
>1000M
0.2
1
0.08
0.5
0.03
0.03
0.005
0.005
0.005
0.005
Typical
0.02
0.02
0.0025
Packaging
All components are supplied loose packed in either plastic bags
or panel boxes. Quantity per box will depend on resistor size.
© 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 B · 03.02
187
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