Low Resistance Metal
Element Resistors
LOB Series
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
General Note
TT electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
© TT electronics plc
11. 11
· Ultra low resistance values
(0.005Ω to 0.1Ω)
· Available in 1, 3 and 5 watt rated packages
· Tolerances from ±1% to ±5%
· Inherently non-inductive (≤.02μH at 0.5MHz)
· Low temperature coefficient of resistance
· High stability over life
* Power Dissipation - The maximum wattage rating depends upon the amount of heat which can be transferred to the surroundings while not exceeding the maximum element
temperature. Ambient air temperature, velocity of cooling air, thermal resistance of heat and the temperature of surrounding objects will affect this transfer, this must be taken
into account when selecting a resistor.
Low Resistance Metal
Element Resistors
LOB Series
•Ultra low resistance values
(0.005Ωto 0.1Ω)
•Available in 1, 3 and 5 watt rated packages
•Tolerances from ±1% to ±5%
•Inherently non-inductive (≤.02µH at 0.5MHz)
•Low temperature coefficient of resistance
•High stability over life
Dimensions (mm)
Type L max. D max. f min. d nom. C
LOB-1
9.9±0.3 3.6±0.2 38.1±3.2 0.813±0.05 33.27
LOB-3
14.22±0.25 5.33±0.25 34.93±3.18 0.81±0.05 33.27
LOB-5
23.37±0.25 8.38±0.25 31.75±3.18 1.02±0.05 42.42
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.
© 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
LOB-1 LOB-3 LOB-5
Continuous power dissipation at 25°C in free air watts 1 3 5
Overload power for 5 seconds watts 5 15 25
Maximum working voltage volts √1xR √3xR √5xR
Maximum storage temperature °C 175 175 175
Electrical Data
Physical Data
Issue B · 03.02
A subsidiary of
TT electronics plc
Welwyn Components
104
L
C
Df
d
contact point contact point
Description
LOBΩSeries power precision metal element resistors feature
resistance values down to 0.005Ωwith virtually no
inductance. Available in 1, 3 and 5 watt rated axial leaded
packages, these resistors are compatible with automatic
insertion equipment.
Applications
•Switchmode and linear power supplies.
•Automotive current-sensing circuits.
•Instrumentation.
Construction
LOBΩSeries resistors feature tinned copper leads welded
directly to a low temperature coefficient resistance element in
a highly automated proprietary process. The leaded resistor
elements are then encapsulated in a moulding compound.
* Power Dissipation - The maximum wattage rating depends upon the amount of heat which can be transferred to the surroundings while not exceeding the maximum element
temperature. Ambient air temperature, velocity of cooling air, thermal resistance of heat and the temperature of surrounding objects will affect this transfer, this must be taken
into account when selecting a resistor.
Low Resistance Metal
Element Resistors
LOB Series
•Ultra low resistance values
(0.005Ωto 0.1Ω)
•Available in 1, 3 and 5 watt rated packages
•Tolerances from ±1% to ±5%
•Inherently non-inductive (≤.02µH at 0.5MHz)
•Low temperature coefficient of resistance
•High stability over life
Dimensions (mm)
Type L max. D max. f min. d nom. C
LOB-1
9.9±0.3 3.6±0.2 38.1±3.2 0.813±0.05 33.27
LOB-3
14.22±0.25 5.33±0.25 34.93±3.18 0.81±0.05 33.27
LOB-5
23.37±0.25 8.38±0.25 31.75±3.18 1.02±0.05 42.42
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.
© 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
LOB-1 LOB-3 LOB-5
Continuous power dissipation at 25°C in free air watts 1 3 5
Overload power for 5 seconds watts 5 15 25
Maximum working voltage volts √1xR √3xR √5xR
Maximum storage temperature °C 175 175 175
Electrical Data
Physical Data
Issue B · 03.02
A subsidiary of
TT electronics plc
Welwyn Components
104
L
C
Df
d
contact point contact point
Description
LOBΩSeries power precision metal element resistors feature
resistance values down to 0.005Ωwith virtually no
inductance. Available in 1, 3 and 5 watt rated axial leaded
packages, these resistors are compatible with automatic
insertion equipment.
Applications
•Switchmode and linear power supplies.
•Automotive current-sensing circuits.
•Instrumentation.
Construction
LOBΩSeries resistors feature tinned copper leads welded
directly to a low temperature coefficient resistance element in
a highly automated proprietary process. The leaded resistor
elements are then encapsulated in a moulding compound.
Low Resistance Metal
Element Resistors
LOB Series
www.bitechnologies.com www.irctt.com www.welwyn-tt.com
General Note
TT electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT electronics’ own data and is considered accurate at time of going to print.
© TT electronics plc
11. 11
0 25 50 75 100
400
300
200
100
0
Resistance (ohms x 10-3)
Temperature Coefficient
of resistance (ppm/°C)
Low Resistance Metal
Element Resistors
LOB Series
© 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
105
Issue B · 03.02
Welwyn Components
% X AM202 DTS - L IMt seT ∆t i nU*R
%%1 ±801 doh t eM) s r uoh 0002 ( e f i l dao L ∆R
%%1 ±701 doh t eMkcoh s l amr ehT ∆R
%%5.0±402 doh t eMnoi tarbiV ∆R
%%5.0±312 doh t eMkcohs l ac i nahceM ∆R
%%5.0±103 doh t eM htg nerts ci rtceleiD ∆R
01>203 doh t eMecnats i ser noi talusnI 11 ohms
0 25 50 75 100 125 150 175
100
90
80
70
60
50
40
30
20
10
0
Ambient Temp (°C)
Rated Power (%)
Power derating percentage vs
Free air ambient temperature
Temperature coefficient of resistance vs
Resistance value
*±0.0005 ohm allowance for test/contact error.
Packaging
Resistors are supplied taped and reeled.
Bulk packaging available.
Ordering Procedure
Example: LOB3 at 10 milliohms and 5% tolerance on a reel of 1250 pieces -
L O B 3 – R 0 1 J I
Type
Value (use IEC62 code)
Tolerance (use IEC62 code)
F
1%
J
5%
H
3%
Note: 1% & 5% preferred
Packing
I
Tape
LOB1
3500/reel
Standard
LOB3
1250/reel
LOB5
800/reel
