Current-Measuring Resistors (Shunts) - Electrical Engineering for Low-Loss Current Measurement and High Signal Stability
Our current-measuring resistors minimize parasitic thermal voltages and reduce thermally induced zero-point errors. By using homogeneous precision alloys such as manganin, aluchrom, and nickel-chromium, we offer measurement applications with long-term stability and optimized temperature coefficients (TCR)—even under alternating thermal loads.
Over 60 years of experience
using FEP shrink technology
Short delivery times
through optimized warehousing
Germany and Switzerland
Dual location strength and reliability
ROTIMA AG—Your Swiss partner for precision electrical engineering since 1964
A second-generation, owner-managed industrial company. Exclusive partnership with Shivalik Bimetal Controls Ltd.
Vacuum Electron Beam Welding (EB Welding)
Homogeneous joints made of high-purity OF copper and manganin/aluchrom. A homogeneous joint zone to prevent local overheating under high current loads, ensuring long-term stability of the electrical connections.
Reduction of Parasitic Thermal Stresses
Optimized temperature coefficients and low thermal stresses compared to copper. Depending on the series and resistive material, low temperature coefficients and low thermal stresses can be achieved. Binding values are specified in the series-specific data sheet.
Application Consulting & Custom Geometries
In-house engineering team for layout review, derating calculations, and footprint optimization. Custom stamping and bending geometries and direct-mount connections to latching relays, energy meters, or battery terminals according to drawings.
Automotive & Quality Standards
Manufactured in accordance with the manufacturer’s IATF 16949 quality management system. Selected product series and variants can be qualified or tested in accordance with AEC-Q200 requirements, with complete batch traceability.
Four-wire Kelvin architecture
Strictly isolated measurement paths to decouple the load current from the voltage signal. The separate voltage tap reduces the influence of lead, trace, and contact resistances on the measurement result.
Security of Supply & TCO Advantage
Central warehouses in Switzerland and Germany offering flexible buffer and consignment storage. Reliability and failure rates are evaluated on a project- or product-series-specific basis using verified manufacturer data.
The Foundation of Precise Control: Accurately Measuring Dynamic Currents
In power electronics, decentralized energy conversion, and electromobility, the accurate measurement of dynamic current waveforms is the foundation of any precise control system. Anyone monitoring currents in the milliampere to kiloampere range must reliably limit the effects of thermal and electrical drift. Conventional thick-film resistors or components with insufficient thermal decoupling quickly reach their limits under continuous load. Heating causes changes in resistance and can influence the measurement result via the Seebeck effect due to parasitic thermal voltages at the interfaces.
Typical Applications and Areas of Use in Power Electronics
The requirements for current-measuring resistors vary depending on the system architecture and switching topology. Our engineers tailor the geometry and alloy selection precisely to the specific load profile of your assembly:
- Battery Management Systems (BMS) & Electric Mobility: Current-sensing resistors for applications in battery management systems, traction inverters, on-board chargers, and other automotive E/E systems. Selection is based on resistance value, current rating, temperature range, tolerance, and required qualification. Manufacturing and quality requirements such as IATF 16949 pertain to the manufacturer’s quality management system; AEC-Q200 specifications are applied only to production runs and require documented qualification.
- Frequency Converters & Drive Technology: In inverter circuits for controlling three-phase motors, SMD power shunts enable rapid current detection and serve as measuring elements for overcurrent and short-circuit protection circuits.
- Smart Metering & Intelligent Metering Infrastructure: For electronic energy meters and precise current measurement systems, Shivalik offers low-resistance shunts and custom stamped-and-bent designs. Kelvin geometries and suitable resistor alloys can reduce the influence of contact resistance and temperature drift. A meter’s compliance with MID or EN 50470 requirements must be demonstrated at the level of the complete measurement system.
- Switched-Mode Power Supplies (SMPS) & DC/DC Converters: In compact power supplies, SMT precision shunts from the SBA 2512 and SBA 2550 series enable reliable heat distribution on the circuit board.
- Medical Technology & Special Applications: Shunt resistors with suitable electrical and thermal properties can be used in medical electronics. Suitability for a specific medical device must be evaluated during device development and system validation. IEC 60601-1 and ISO 13485 are not presented as product approvals for the shunt.
Technical Comparison of Multiple Variants
The following overview compares ROTIMA's model types and product lines (the SBA 2512 and SBA 2550 are listed separately):
| Physical parameter | 01a. SMT chip (SBA 2512) | 01b. High-Power (SBA 2550) | 02. High-Current (SBB 5930) | 03. 4-wire Kelvin (SBC 4026) | 04. Open Frame (SBD 4512/4524) | 05. Busbar (EB-Welding) | 06. Custom Punching and Bending |
|---|---|---|---|---|---|---|---|
| Rated Resistance (R) | 0.2 mΩ - 10 mΩ | 0.045 mΩ - 0.50 mΩ | 0.1 mΩ - 3.0 mΩ | 0.2 mΩ - 5.0 mΩ | 1 mΩ - 50 mΩ | project-specific | project-specific |
| Rated Power (P70) | 1.5 W - 6.0 W | up to 12 W | 5.0 W - 15.0 W | 3.0 W - 12.0 W | 2.0 W - 5.0 W | as interpreted | application-specific |
| Continuous Current (Imax) | as specified in the data sheet | as specified in the data sheet | as specified in the data sheet | as specified in the data sheet | as specified in the data sheet | project-specific | as interpreted |
| Temperature Coefficient (TCR) | According to the standard data sheet / depending on material and type | According to the standard data sheet / depending on material and type | According to the standard data sheet / depending on material and type | According to the standard data sheet / depending on material and type | According to the standard data sheet / depending on material and type | According to the standard data sheet / depending on material and type | According to the standard data sheet / depending on material and type |
| Thermal Power vs. Copper | Low; depends on the alloy and type, as specified in the data sheet | Low; depends on the alloy and type, as specified in the data sheet | Low; depends on the alloy and type, as specified in the data sheet | Low; depends on the alloy and type, as specified in the data sheet | Low; depends on the alloy and type, as specified in the data sheet | Low; depends on the alloy and type, as specified in the data sheet | Low; depends on the alloy and type, as specified in the data sheet |
| Tolerance Classes | depending on the series and resistance value | 1 %, 2 %, 5 % | 1 %, 5 % | 1 %, 2 %, 5 % | 1 %, 3 %, 5 % | project-specific | project-specific |
| Self-inductance (L) | low-induction | low-induction | low-induction | reduced (4-wire) | low-induction | geometry-dependent | geometry-dependent |
| Joining Processes / Materials | Manganin/Aluchrom | Manganin/Aluchrom | Cu-Mn / NiCr | Manganin / OF-Cu | electron beam | Vacuum EB Welding | Stamping and Bending / Manganin |
| Distinctive Feature | Flat-pack chip design | Advanced Features | Solid copper block | Separate voltage tap | Decoupled Geometry | Monolithic Rail | Direct Mounting of Relays/Electric Meters |
| Main Application | Electronics / Assemblies | Power Electronics | Drive Inverter / EV | Measurement Systems / Meters | Case without a fan | BMS / Traction Battery | Latching Relay / e-Meter |
| Standards / QMS | IATF 16949 (QMS) | IATF 16949 (QMS) | IATF 16949 (QMS) | IATF 16949 (QMS) | IATF 16949 (QMS) | IATF 16949 (QMS) | ISO 9001 (QMS) |
Do you have any questions about our products:
Current-measuring resistors (shunts)
Current-measuring resistors (shunts)
Design Types & Product Variants in Detail
Electron-beam-welded busbar current-measuring resistors for high-current BMS (off-board)
Custom busbar shunts are designed on a project-by-project basis based on current, resistance, geometry, temperature, connection type, and mechanical requirements.
These heavy-duty, high-current shunts use electron beam welding (EB welding) to join high-purity copper with precision alloys. In battery management systems (BMS), they enable a reliable connection to busbars.
These heavy-duty, high-current shunts use electron beam welding (EB welding) to join high-purity copper with precision alloys. In battery management systems (BMS), they enable a reliable connection to busbars.
| Rated Resistance Range | project-specific (e.g., sub-milliohm) |
| Continuous Current Rating | Designed specifically for each project according to requirements |
| Joining Process for Contact Rails | Vacuum EB Welding |
| Material Combination | OF-CU / Manganin / Aluchrom |
| Mechanical Connection | Screw connection or welded connection according to the CAD drawing |
| Tolerances & TCR | in accordance with the project specification and data sheet |
| Compliance with Standards | Project-Based Qualification Exams |
SMT Precision Shunts in a Compact Chip Package (SBA 2512 Series)
When currents need to be monitored in densely populated assemblies with limited space, metal-alloy-based shunt resistors provide reliable heat dissipation into the circuit board geometry.
The SBA 2512 series uses precision alloys such as manganin and aluchrom to reduce temperature coefficients. Please refer to the manufacturer’s data sheet for binding specification values.
The SBA 2512 series uses precision alloys such as manganin and aluchrom to reduce temperature coefficients. Please refer to the manufacturer’s data sheet for binding specification values.
| Rated Resistance Range | 0.2 mΩ to 10.0 mΩ |
| Rated Power (P70) | 1.5 W to 6.0 W (depending on the size) |
| Resistance Tolerance Classes | depending on the series and resistance value |
| Temperature Coefficient (TCR) | as specified in the product data sheet |
| Thermal Stress on Copper | ＜ 1 µV/K |
| Operating temperature range | -55 °C to +170 °C |
| Housing Design | SMD / SMT 2512 |
| Resistance material | Cu-Mn-Sn / Cu-Mn / Aluchrom / NiCr (depending on the variant) |
| Manufacturing Standard | Manufacturer QMS: IATF 16949 / ISO 9001 |
High-Power SMT Chip Measurement Resistors (SBA 2550 Series)
For applications with higher power requirements in a compact footprint, the standard portfolio—featuring the SBA 2550 size—offers extended rated power capacities of up to 12 watts.
| Rated Resistance Range | 0.1 mΩ to 1.0 mΩ |
| Rated Power (P70) | up to 12 W in the standard portfolio |
| Resistance Tolerance Classes | 1 %, 2 %, 5 % |
| Temperature Coefficient (TCR) | as specified in the product data sheet |
| Thermal Stress on Copper | ＜ 1 µV/K |
| Housing Design | SMD / SMT 2550 |
| Resistance material | Manganin / Aluchrom |
| Manufacturing Standard | Manufacturer-certified to IATF 16949 / ISO 9001 |
High-Current SMT Power Shunts with Extended Ground Plane (SBB 5930 Series)
In dynamic drive inverters and power converters, high current loads cause the component to heat up. The SBB 5930 series features increased thermal mass and wide copper terminals for dissipating power loss.
| Rated Resistance Range | 0.1 mΩ to 3.0 mΩ |
| Rated Power (P70) | 5.0 W to 15.0 W |
| Resistance Tolerance Classes | 1 %, 5 % |
| Temperature Coefficient (TCR) | as specified in the product data sheet |
| Housing Design | SMD / SMT 5930 |
| Resistance material | Cu-Mn-Sn / Cu-Mn / NiCr / Aluchrom (depending on the variant) |
| Limit Values / Pulse Load | according to the verified manufacturer's specification sheet |
| Manufacturing Certification | IATF 16949 Quality Management System |
Low-impedance chip current sense resistors with a four-wire Kelvin connection (SBC 4026 Series)
For low resistance values, the separate voltage tap in the four-wire measurement significantly reduces the influence of lead, trace, and contact resistances on the measurement result. The SBC 4026 series features dedicated Kelvin connections directly within the chip footprint, thereby decoupling load current and signal lines.
| Manufacturing Standard | SMD 4026 |
| Rated Resistance Range | 0.2 mΩ to 5.0 mΩ |
| Rated Power (P70) | 3.0 W to 12.0 W |
| Resistance Tolerance Classes | 4-wire (Kelvin method) |
| Temperature Coefficient (TCR) | 1%, 2%, 5% |
| Housing Design | as specified in the product data sheet |
| Connection Topology | Manufacturer-certified to IATF 16949 / ISO 9001 |
Open-frame current sense resistors with Kelvin technology (SBD 4512/4524 Series)
Open-frame designs allow for improved heat dissipation into the ambient air. The SBD 4512 and SBD 4524 series feature 4-wire technology for precise measurements in power electronics applications.
| Rated Resistance Range | 1,0 - 50,0 mΩ |
| Rated Power (P70) | 2.0 W to 5.0 W |
| Connection Topology | 4-wire (Kelvin method) |
| Resistance Tolerance Classes | 1 %, 3 %, 5 % |
| Temperature Coefficient (TCR) | Depending on size and type, as specified in the standard data sheet |
| Housing Design | Depending on size and type, as specified in the standard data sheet |
| Manufacturing Standard | Depending on size and type, as specified in the standard data sheet |
Other product lines from Shivalik Bimetal Controls Ltd.
The location of the shunt determines the geometry, joining method, and thermal connection. ROTIMA and Shivalik Bimetal Controls Ltd. offer their own product lines for both options.
On-Board
We supply on-board shunts from Shivalik Bimetal Controls Ltd. for precise current measurement with shunts with low energy loss. Our experts evaluate electrical load, heat dissipation and short-time overload for BMS, IBS, energy measurement systems, shunts for electrical drives as well as shunt resistors and converters.
Off-Board
Our off-board shunts are resistors from Shivalik Bimetal Controls Ltd. and offer excellent heat dissipation and high resistance stability. If you want to buy current sense resistors, ROTIMA is the right place for you. Our range includes metal foil resistors, wirewound resistors as well as thick film resistors and thin film resistors from high-precision manufacturing for industrial energy measurement systems.
Do you have any questions about our products:
Current-measuring resistors (shunts)
Current-measuring resistors (shunts)
Technical Parameters and Design Data
The following overview summarizes the physical and technical specifications of the shunt resistor portfolio:
| Parameter / Physical parameter | Specified Service Area (ROTIMA Portfolio) |
|---|---|
| Rated Resistance Range (R) | Starting at 0.025 mΩ; custom values available on a project-by-project basis |
| Rated Power (P70) | 1.5 W to 15.0 W (standard SMD portfolio); higher power ratings available on a project-by-project basis |
| Temperature Coefficient (TCR) | Low TCR values depending on the material and series, as specified in the data sheet |
| Thermal Voltage vs. Copper (Thermal EMF) | Low thermal stresses depending on the resistance alloy |
| Resistance Tolerance Classes | Depends on the series and resistance value, as specified in the standard data sheet; the standard portfolio includes, among others, 1%, 2%, 3%, 4%, 5%, and 10% |
| Parasitic self-inductance (L) | Low-inductance geometries for high-frequency switching operations |
| Operating temperature range | -55 °C to +170 °C (according to the series specification) |
Materials, Joining Processes, and Thermal Stability
The quality of a current-measuring resistor is determined by the material interface. Carefully matched material combinations reduce thermoelectric drift effects:
- Manganin (Cu-Mn-Ni alloys): Low thermoelectric voltage relative to copper and long-term stability within the typical operating temperature range.
- Aluchrom & nickel-chromium (NiCr): Used for higher ohm ranges and extended temperature ranges with high specific resistivity.
- Vacuum electron beam welding (EB welding): Theprimary welding process for joining copper terminals (OF copper) to the active resistance element. It provides a homogeneous fusion zone and high mechanical strength.
Service, Logistics, and Delivery Reliability
- High long-term stability: Components are designed for measurement applications requiring long-term stability.
- Automation-ready packaging: Supplied in standard tape-and-reel systems for automated SMT assembly processes.
- Buffer Stock & Consignment Inventory: Central warehouses in Switzerland and Germany to ensure availability for mass production needs.
Quality Assurance, Testing Procedures, and Standards
- IATF 16949 Quality Management: Components are manufactured in accordance with the manufacturer’s certified quality management systems, ensuring complete traceability.
- AEC-Q200 Qualification Testing: Selected product series/variants can be qualified or tested in accordance with AEC-Q200 requirements.
- In-House Testing: Verification of electrical parameters on calibrated test benches as part of quality control.
Design, Engineering, and Technical Decision-Making Criteria
When sizing current-measuring resistors, ROTIMA's engineers provide support with the following steps:
- Measurement range vs. self-heating: Balancing sufficient signal voltage for the amplifier with limiting power dissipation (P = I² · R).
- Kelvin connection in the PCB layout: For low resistance values, symmetrical 4-wire signal routing reduces the effects of trace and contact resistance.
- Thermal decoupling & derating: Compliance with the permissible power dissipation according to the derating curve at elevated ambient temperatures.
Do you have any questions about our products:
Current-measuring resistors (shunts)
Current-measuring resistors (shunts)
Why ROTIMA Is Your Partner for Current Measurement Resistors
ROTIMA combines engineering application consulting with the IATF 16949-certified manufacturing program of Shivalik Bimetal Controls Ltd. Our specialists support your development department from design through to series production.
Frequently Asked Questions
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Electric Mobility, Automotive & Battery Management (BMS)
Frequency Converters, Drive Technology & Power Electronics
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