Current Sensing Resistors
Chip
±0.05%
Tightest Tolerance
Tightest Tolerance
3 ppm/°C
Best TCR
Best TCR
12,000A
Max Rated Current
Max Rated Current
8 Categories
Technologies
Technologies
Technologies:
AEC-Q200
l
Low Resistance
l
Precision 4-Terminal
l
Power Metering
What Is a Current Sensing Resistor?
A practical overview for engineers and procurement teams evaluating resistive solutions.
A current sensing resistor — also called a shunt resistor — is a precision low-resistance component inserted in series with a load to measure current flow. By measuring the small voltage drop across the shunt using Ohm's Law (V = I × R), the current through the circuit can be accurately determined without interrupting the load path. The fundamental requirements for a good current sense resistor are very low resistance (to minimize power loss and voltage drop), tight tolerance (for measurement accuracy), and low TCR (so the resistance — and therefore the measurement — stays stable as the component heats up under load).
RARA offers an industry-leading 8 sub-categories of current sensing resistors: AEC-Q200 automotive-qualified shunts, low resistance metal alloy and metal foil types, chip SMD current sense resistors, precision four-terminal Kelvin-connected types, through hole variants, high power shunts up to 250W, power metering shunts, and high amperage panel shunts rated up to 12,000A.
At the precision end, RARA's HPS, UHPS, and PSS high-power precision shunts achieve ±0.05% tolerance and TCR as low as 3 ppm/°C — critical for accurate energy metering and battery coulomb counting in EV systems. At the high-amperage end, the RSR and SH-T panel shunts handle up to 12,000A at 50–100mV drop for utility metering and industrial current measurement.
Construction Technologies
-AEC-Q200 automotive shunts
-Low resistance metal alloy & foil
-Chip SMD current sense
-Precision 4-terminal (Kelvin)
-Through hole shunts
-High power (up to 250W / 387A)
-Power metering shunts
-High amperage (up to 12,000A)
-AEC-Q200 automotive shunts
-Low resistance metal alloy & foil
-Chip SMD current sense
-Precision 4-terminal (Kelvin)
-Through hole shunts
-High power (up to 250W / 387A)
-Power metering shunts
-High amperage (up to 12,000A)
Key Advantages
-Max current: 12,000A (RSR, SH-T)
-Min resistance: 25μΩ (PCBS module)
-Tolerance: ±0.05% (HPS, UHPS, PSS)
-TCR: 3 ppm/°C (HPS, UHPS, PSS)
-AEC-Q200 qualified models available
-Max current: 12,000A (RSR, SH-T)
-Min resistance: 25μΩ (PCBS module)
-Tolerance: ±0.05% (HPS, UHPS, PSS)
-TCR: 3 ppm/°C (HPS, UHPS, PSS)
-AEC-Q200 qualified models available
With eight current sensing sub-categories, RARA offers the broadest range of current sensing resistors available from a single ISO-certified supplier — from AEC-Q200 chip shunts to 12,000A panel shunts.
Applications
Where RARA current sensing resistors are deployed in the field.
EV Battery Management & Coulomb Counting
AEC-Q200 qualified shunts (BCS, LRA, ECS, BWR, TCS) and high-precision types (HPS, UHPS at ±0.05%, 3 ppm/°C) are the heart of battery management systems — measuring charge and discharge current continuously to calculate state-of-charge. RARA's PCBS module handles up to 1000A for high-voltage EV battery packs.
AEC-Q200 qualified shunts (BCS, LRA, ECS, BWR, TCS) and high-precision types (HPS, UHPS at ±0.05%, 3 ppm/°C) are the heart of battery management systems — measuring charge and discharge current continuously to calculate state-of-charge. RARA's PCBS module handles up to 1000A for high-voltage EV battery packs.
Motor Drive & Inverter Current Feedback
Variable frequency drives, servo amplifiers, and inverters use chip current sense resistors (CS, CSTN, RTX) and precision through-hole types (PCR4T, HPCR4T) in phase current measurement loops — providing the current feedback signal for torque control, overload protection, and fault detection.
Variable frequency drives, servo amplifiers, and inverters use chip current sense resistors (CS, CSTN, RTX) and precision through-hole types (PCR4T, HPCR4T) in phase current measurement loops — providing the current feedback signal for torque control, overload protection, and fault detection.
Power Supply & UPS Current Monitoring
Switch-mode power supplies, UPS systems, and DC-DC converters use low-resistance chip shunts (LR, MR, MFF series) for output current monitoring and current-mode control. The tight tolerance and low TCR of these types ensures accurate regulation across the full load and temperature range.
Switch-mode power supplies, UPS systems, and DC-DC converters use low-resistance chip shunts (LR, MR, MFF series) for output current monitoring and current-mode control. The tight tolerance and low TCR of these types ensures accurate regulation across the full load and temperature range.
Industrial Power Metering
The PMS power metering shunt (3W, 15–100A) and high-amperage RSR / SH-T / SH-L panel shunts (up to 12,000A, 50–100mV drop) are used in industrial energy meters, substation metering panels, and utility revenue meters — where long-term accuracy and low TCR are mandatory for billing-grade measurement.
The PMS power metering shunt (3W, 15–100A) and high-amperage RSR / SH-T / SH-L panel shunts (up to 12,000A, 50–100mV drop) are used in industrial energy meters, substation metering panels, and utility revenue meters — where long-term accuracy and low TCR are mandatory for billing-grade measurement.
Solar & Renewable Energy Systems
Solar inverters and battery energy storage systems require accurate current measurement across wide current ranges and temperature swings. RARA's LT and IRHF high-power precision shunts (50–500A, TCR 15–30 ppm/°C) are well-suited to the continuous-duty measurement demands of renewable energy installations.
Solar inverters and battery energy storage systems require accurate current measurement across wide current ranges and temperature swings. RARA's LT and IRHF high-power precision shunts (50–500A, TCR 15–30 ppm/°C) are well-suited to the continuous-duty measurement demands of renewable energy installations.
Test & Measurement Instruments
Current clamp meters, precision power analyzers, and laboratory current sources use four-terminal Kelvin-connected shunts (AH, PBV/PBH, RMF) where the sense connections are independent of the current path — eliminating lead resistance error and enabling sub-milliohm measurements at high accuracy.
Current clamp meters, precision power analyzers, and laboratory current sources use four-terminal Kelvin-connected shunts (AH, PBV/PBH, RMF) where the sense connections are independent of the current path — eliminating lead resistance error and enabling sub-milliohm measurements at high accuracy.
Product Series Chip
Select models from our current sensing lineup. Download individual datasheets for full specifications, dimensions, and ordering codes.
Model: CS
Resistor type: Current sensing
Description: Chip
Power Rating: 1/20W~3W
Resistance (Ω): 1m~8000m
Tolerance (%): ±1, ±2, ±5
TCR (ppm/C): 100, 1000
Model: CSTN
Resistor type: Current sensing
Description: Chip
Power Rating: 1/16W~3W
Resistance (Ω): 50m~1000m
Tolerance (%): ±0.5, ±1
TCR (ppm/C): 50, 100, 200
Model: RS
Resistor type: Current sensing
Description: Thick film chip
Power Rating: 1/16W~2W
Resistance (Ω): 10m~976m
Tolerance (%): ±1, ±5
TCR (ppm/C): 200, 1500
Model: RTX
Resistor type: Current Sensing
Description: Chip
Power Rating: 1/8W~2W
Resistance (Ω): 50m~1000m
Tolerance (%): ±0.5, ±1, ±2, ±5
TCR (ppm/C): 75-300
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.
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.
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.
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.
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.
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100B-11L, 138 Cheongneung-
daero 410beon-gil,
Namdong-gu, Incheon
TEL : +82-70-4355-4327
FAX : +82-32-817-4328
Email: osm1@raraohm.com
daero 410beon-gil,
Namdong-gu, Incheon
TEL : +82-70-4355-4327
FAX : +82-32-817-4328
Email: osm1@raraohm.com
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