Precision Metal
Precision Metal
Film Resistors
Film Resistors
Welwyn Components
PR series
PR series
Low cost precision resistors
Low costdown to ±0.1%
Tolerances precision resistors
Tolerances to 15ppm/°C
TCR down down to ±0.1%
TCR down to 15ppm/°C
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Electrical Data
PR4
Power rating at 70°C
watts
Resistance range
ohms
Limiting element voltage
volts
PR5
0.5
0.25
100R – 1M
250
350
TCR (20°C to 70°C)
ppm/°C
≤240K: 15, 25, 50
Resistance tolerance
%
≤500K: 0.1, 0.25, 0.5, 1
Standard values
>240K: 25, 50
>500K: 0.25, 0.5, 1
E24, E96
Thermal impedance
°C/watt
Ambient temperature range
140
°C
112
-55 to 155
Physical Data
Dimensions (mm) & Weight (g)
Type
L Max
D Max
f min
d nom
PC
mounting
centres
PR4
6.2
2.5
21
0.6
10.2
PR5
9.0
3.6
19.6
0.8
12.7
Min.
bend
radius
Wt. nom
0.6
0.3
1.2
0.5
Construction
Material
Strength
This permits a well defined body length (clean lead to clean
lead dimension L).
D
L
f
Terminations
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.
d
Marking
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
25ppm/°C resistors are colour coded with 5 bands. The other
grades have an additional 6th band indicating TCR which is
orange for 15ppm/°C and red for 50ppm/°C.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuits.
General Note
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
TT electronics 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.
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
A subsidiary of
TT electronics plc
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670
© TT electronics plc822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
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