Precision Metal
Film Resistors
PR series
Welwyn Components
•
Low cost precision resistors
•
Tolerances down to ±0.1%
•
TCR down to 15ppm/°C
Electrical Data
PR4
Power rating at 70°C
Resistance range
Limiting element voltage
TCR (20°C to 70°C)
Resistance tolerance
Standard values
Thermal impedance
Ambient temperature range
°C/watt
°C
140
-55 to 155
watts
ohms
volts
ppm/°C
%
250
≤240K:
15, 25, 50
≤500K:
0.1, 0.25, 0.5, 1
0.25
100R – 1M
350
>240K: 25, 50
>500K: 0.25, 0.5, 1
112
0.5
PR5
E24, E96
Physical Data
Dimensions (mm) & Weight (g)
PC
mounting
centres
10.2
12.7
Min.
bend
radius
Wt. nom
d
Type
PR4
PR5
L Max
6.2
9.0
D Max
2.5
3.6
f min
21
19.6
d nom
0.6
0.8
0.6
1.2
0.3
0.5
D
L
f
Construction
The resistance element is a precisely controlled thin film of
metal alloy sputtered on to a high purity ceramic core,
protected by a moisture-resistant, high dielectric strength
coating applied so that terminations remain completely clear.
This permits a well defined body length (clean lead to clean
lead dimension L).
Terminations
Material
Strength
Solderability
Hot tin dipped 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
Resistors are colour coded with 5 bands. IEC 62 colours are
used.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuits.
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
© 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
07. 08
182
Precision Metal
Film Resistors
PR series
Welwyn Components
Performance Data
Maximum
Load: 1000 hours at 70°C
Derating from rated power at 70°C
Short term overload
Climatic
Climatic category
Long term damp heat
Temperature rapid change
Resistance to solder heat
Vibration and bump
Insulation resistance
Voltage proof
∆
R %
∆
R %
∆
R %
∆
R %
ohms
volts
∆
R %
∆
R %
∆
R %
0.5
zero at 155°C
0.25
0.5
55/125/56
0.5
0.25
0.25
0.1
> 1G
PR4: 500 min, PR5: 700 min
Packaging
All PR resistors are supplied tape packed ready for loading on
to automatic sequencing and insertion machines.
Component wires will not protrude beyond the outside edge
of the tapes.
Alternative packaging available by request.
Lead formed resistors can also be supplied. Standard options
of Lancet, Radial and Goalpost forming are available.
6
f
1
52
f
2
6
5
Body location f
1
– f
2
≤
1.4 mm
Ordering Procedure
Example: PR4 with TCR of 15ppm/ °C at 10 kilohms and 0.1% tolerance in an ammo pack box
of 5000 pieces -
PR4Y
–
10KB
I
Type
TCR
Y
C
15 ppm/
°C
25 ppm/
°C
50 ppm/
°C
Value (use IEC62 code)
Tolerance (use IEC62 code)
B
C
0.1%
0.25%
D
F
0.5%
1%
Packing
I
Ammo
PR4
PR5
5000/box
2500/box
Standard
© 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
07. 08
183
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