Vitreous Enamelled
Wirewound Resistors
V700 (RB Style) Series
Welwyn Components
•
BS/CECC approved
•
Stability for harsh environments
•
Overload characteristics ideal for
protection circuits
•
•
•
High stability and reliability
High power dissipation for size
Impervious lead free vitreous enamel coating
Electrical Data
V757
(RB57)
Power rating at 25°C
Resistance range
Limiting element voltage
TCR
Resistance tolerance
watts
ohms
volts
ppm/°C
%
7
0R1 to 20K
200
5
V758
(RB58)
11.0
0R2 to 82K
400
Typically: +75
V759
(RB59)
3.0
0R1 to 10K
100
V760
(RB60)
8.0
0R1 to 56K
250
Maximum +120
V761
(RB61)
5.0
0R1 to 15K
160
Closer tolerances to special order
Approved CECC 40201 - 001
Power rating at 25°C
Power rating at 70°C
Resistance range
Limiting element voltage
TCR
Resistance tolerance
Standard values
Thermal impedance
Ambient temperature range
°C/watt
°C
44
watts
watts
ohms
volts
ppm/°C
%
5
32
6.5
5.6
0R1 to 20K
160
>20 ohms ±500
5
88
-55 to 200
3.0
2.6
0R1 to 10K
63
8.0
6.9
250
≥20
ohms -50 +250
5
36
5
58
5.0
4.3
160
0R1 to 56K 0R15 to 15K
E24 preferred. Other values to special order
* See temperature rise in graph Application Notes
Physical Data
Maximum Dimensions (mm) and Weight (g)
Type
V757 (RB57)
V758 (RB58)
V759 (RB59)
V760 (RB60)
V761 (RB61)
L max
22.2
47
12.7
36
23
D max
8
11
5.6
10.0
7.0
f min
30
30
30
30
30
d max
0.88
0.88
0.88
0.88
0.88
Wt. Nom
2
9
1
4
2
d
D
L
f
Construction
A high purity ceramic substrate is assembled with force fit
end caps to which are welded the termination wires.
The resistive element is wound on the substrate and welded to
the caps; the vitreous enamel protective coating is then applied.
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
87
Vitreous Enamelled
Wirewound Resistors
V700 (RB Style) Series
Terminations
Material
Copper clad steel wire, nickel plated and
solder-coated.
Strength
Welwyn Components
The terminations meet requirements of
IEC 68.2.21.
Solderability
The terminations meet the requirements of IEC
115-1, Clause 4.17.3.2.
Performance Data
CECC
40201-001
Load at rated power: 1000 hrs
Dry heat: 1000 hours at 200°c
Shelf life: 12 mths at room temp
Derating from rated power at 25°C
Short term overload
Climatic
Climatic category
Long term damp heat
Temperature rapid change
Resistance to solder heat
Vibration
Noise (µV/V in a decade of freqency)
Shock
Pulse handling
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
5
5
Not specified
Not specified
2
5
55/200/56
5
1
1
1
Not specified
1
0.2
Data available by request
1.5
0.5
55/200/56
0.05
0.5
0.25
0.25
zero
0.05
5
2
0.03
See derating curve
0.5
0.2
55/200/56
0.02
0.05
0.03
0.05
Actual Performance
Maximum
Typical
3.5
1
0.02
Application Notes
% of Rated Power
The terminations should not be bent closer than 1.6mm from
the body, and the recommended minimum bend radius is
1.2mm. If resistors are to dissipate full rated power, the
terminations should not be soldered closer than 4mm from
the body.
When cold, vitreous enamel has excellent insulation
resistance. In common with all insulants the specific resistance
of the enamel decreases with increase in temperature.
Therefore, resistors operated at near maximum temperature
cannot be classed as insulated and should not be used in
contact with any conducting material.
Care must be taken when determining clearance distance
between the resistor body and the printed circuit board or
other components to ensure these are not over heated.
Resistance is measured 6mm from the body.
116
100
Derating Curve
54
0
25
70
200
315
Ambient temperature
°C
Packaging
For RB59 and RB61 the standard method of packaging is
taped and Ammo Packed.
For RB57, the standard method of packaging is taped and
reeled. RB58 and RB60 are loose packed in boxes.
Alternative packaging available by request.
Type
V759
V757
V761
L
63
73
73
6
f
1
L
f
1
– f
2
≤
1.4 mm
f
2
6
10
© 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
88
Vitreous Enamelled
Wirewound Resistors
V700 (RB Style) Series
Welwyn Components
Ordering Procedure
Example: V757 (RB57) at 3.3 kilohms and 5% tolerance on a reel of 700 pieces
–
RB57
–
3K3J
I
Type
Value (use IEC62 code)
Tolerance (use IEC62 code)
J
5%
Packing
I
Ammo
Tape
Bulk
RB59, RB61
RB57
RB58, RB60
1000/box
700/reel
50/box
Standard
For CECC released product state on order the CECC number. Example:
RB57-3K3JI CECC40201-001
For SnPb finish instead of Pb-free replace the packing suffix with
PB.
Example:
RB57-3K3JPB
© 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
88
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