BWH Series Low Ohmic EB Welded SMD Precision Resistors
5W rated continuous power
Constant current handling up to 100A (0.3mΩ variants)
Resistance range 0.3mΩ to 3mΩ
High conductivity copper connectors
Excellent long-term stability
Operating temperature range −55°C to +170°C
Maximum solder temperature 350°C for 30 seconds
Tolerance options ±1%, ±3% and ±5%
TCR ±100ppm/°C and ±300ppm/°C depending on resistance value
Solid metal construction, frame resistant
AEC-Q200 qualified; RoHS and REACH certified
What are the BWH Series Low Ohmic EB Welded SMD Precision Resistors?
The BWH Series is a range of low-ohmic, surface-mount precision shunt resistors manufactured using electron beam (EB) welding technology on a solid metal construction. Rated at 5W continuous power, the BWH is designed for high-current measurement and sensing applications where stability, low resistance, and thermal resilience are critical. The solid metal body provides mechanical robustness and efficient heat dissipation, making these resistors suitable for demanding industrial and automotive environments.
The resistance range spans 0.3mΩ to 3mΩ, with the 0.3mΩ variant capable of handling constant currents up to 100A. Tolerance options of ±1%, ±3%, and ±5% are available, with a temperature coefficient of resistance (TCR) of ±300ppm/°C for the lowest resistance values and ±100ppm/°C for values of 1mΩ and above. The wide operating temperature range of −55°C to +170°C, combined with a maximum solder temperature tolerance of 350°C for 30 seconds, ensures reliable performance across extreme thermal conditions encountered in power electronics and automotive applications.
A key feature of the BWH Series is its use of high conductivity copper connectors joined by electron beam welding, a process that produces strong, low-resistance joints without the use of filler materials. This construction method contributes to the excellent long-term stability of the series, as verified by 1000-hour load life and high-temperature exposure tests showing resistance change within tightly controlled limits. The solid metal frame construction further adds resistance to mechanical shock and vibration.
The BWH Series carries AEC-Q200 qualification, confirming its suitability for automotive-grade applications, and is fully RoHS and REACH certified. These resistors are offered in a through-hole package format and are available in the BWH05 model designation, with dimensions matched to the selected resistance value. The combination of extremely low resistance, high current capacity, and automotive qualification makes the BWH Series a versatile choice wherever precise, stable current sensing is required in high-power circuits.
BWH Series Low Ohmic EB Welded SMD Precision Resistors Specifications
A practical overview for engineers and procurement teams evaluating resistive solutions.
Model: BWH
Resistor type: Current Sensing
Description: Through Hole
Power Rating: 3W~5W
Resistance (Ω): 0.3m~3m
Tolerance (%): ±1, ±2, ±5
TCR (ppm/C): 100, 300
Applications of the BWH Series Low Ohmic EB Welded SMD Precision Resistors
Where RARA current sensing resistors are deployed in the field.
Current sensing and feedback circuits — precision shunt measurement in motor drives and power converters
Automotive power electronics — on-board chargers, battery management systems, and powertrain control units
Power modules — integrated current monitoring within IGBT and MOSFET power assemblies
Frequency converters and variable-speed drives — DC bus and phase current sensing
Inverter systems — real-time current feedback for closed-loop control
Low-inductance applications — high-frequency switching circuits requiring non-inductive shunt elements
Battery test and formation equipment — high-current charge and discharge measurement
Renewable energy systems — solar inverters and energy storage current monitoring
Welding and plasma power supplies — high-current process control and protection
Industrial automation and robotics — servo drive current sensing and overload detection
Related Products of the BWH Series Low Ohmic EB Welded SMD Precision Resistors
Model: CSR
Resistor type: Through hole shunt
Description: Through hole 2 terminal
Rated Current: 2A-12A
Resistance (Ω): 20m~200m
Tolerance (%): ±5, ±10
TCR (ppm/C): 260
Model: BWT
Resistor type: Current Sensing
Description: Through Hole
Power Rating: 2W, 5W
Resistance (Ω): 0.5m~10m
Tolerance (%): ±1, ±5
TCR (ppm/C): 50
Model: MPR
Resistor type: Current Sensing
Description: Through Hole
Power Rating: 3W~20W
Resistance (Ω): 5m~400m
Tolerance (%): ±1, ±5
TCR (ppm/C): 260 max.
Model: PCR4T
Resistor type: Current sensing
Description: Through Hole
Rated Current: 35-65A
Resistance (Ω): 0.5m-4m
Tolerance (%): ±0.5, ±1, ±5
TCR (ppm/C): 30
Why Choose RARA Current Sensing Resistors
What sets RARA apart for engineers and procurement managers in industrial and automotive markets.
01
8 Sub-Categories
No other single supplier covers AEC-Q200 chip shunts, milliohm precision types, four-terminal Kelvin shunts, power metering, and 12,000A panel shunts under one ISO-certified roof.
02
Extreme Precision
HPS, UHPS, and PSS precision shunts deliver ±0.05% tolerance and 3 ppm/°C TCR — meeting the accuracy demands of EV battery coulomb counting, precision power analyzers, and billing-grade energy metering.
03
Automotive Qualified
Multiple AEC-Q200 certified models (BCS, LRA, ECS, BWR, TCS, PCBS) with IATF 16949 manufacturing certification — covering EV battery management, motor control, and charging applications.
04
Global Track Record
Trusted by Tesla, GM Korea, Proterra, Siemens, Rockwell, and Schneider Electric — deployed in EV powertrains, industrial drives, and utility metering systems across six continents.
