Precision Metal
Film Resistors
Welwyn Components
PR series
• Low cost precision resistors
Tolerances down to ±±0.1
•
TCR down to .5ppm/°C
•
Electrical Data
PR4
0.25
PR5
Power rating at 70°C
Resistance range
watts
ohms
volts
0.5
100R – 240K
250
100R – 1M
Limiting element voltage
TCR*
350
ppm/°C
%
25
25
0.1, 0.25, 0.5, 1
E192
Resistance tolerance
Standard values
0.1, 0.25, 0.5, 1
E192
Thermal impedance
Ambient temperature range
°C/watt
°C
140
112
-55 to 155
*15ppm/°C available by request
Physical Data
Dimensions (mm) & Weight (g)
PCB
Min.
mounting bend
Type
PR4
PR5
L Max
6.2
D Max
2.5
f min
21
d nom
0.6
centres
10.2
radius
Wt.nom
d
D
0.6
0.3
0.5
L
f
9.0
3.6
19.6
0.8
12.7
1.2
Terminations
Material
Strength
Construction
Solder-coated copper wire.
The terminations meet the requirements of
IEC 68.2.21
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
Solderability
The terminations meet the requirements of
IEC 115-1, Clause 4.17.3.2
coating applied so that terminations remain completely clear.
This permits a well defined body length (clean lead to clean
lead dimension L).
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
Issue C · 04.03
182
TTELEC [ TT Electronics ]
