FSHY  Resistor Series Complete Analysis

I. Brand Introduction

Foshan Lucky Electric Accessories Co., Ltd. (FSHY) was established in December 2004 as a Sino-foreign joint venture with a registered capital of RMB 15 million. The company specializes in manufacturing milli-ohm level high-precision alloy resistors, shunts, thermostat components, bimetal and trimetal components, and precision molds. In November 2021, the company was wholly acquired by Foshan Vishayton Co., Ltd., gaining dedicated electron beam welding production lines. FSHY is currently one of the few manufacturers in China's beam-welded alloy current-sensing resistor industry with complete R&D, manufacturing, and testing capabilities in alloy materials, electron beam welding, precision structural processing, and component reliability.

FSHY operates 31 precision metal processing equipment units including wire EDM machines, 96 precision stamping equipment units from German KAISER and Japanese ISIS, 20 vacuum heat treatment units, 60 precision trimming units, power testing equipment, temperature drift testing equipment, Japanese AE and Hioki precision resistance instruments, taping machines, visual sorting machines, and laser equipment—totaling nearly 200 units. The company supplies over 1 billion components to customers annually. FSHY holds ISO9001/14001 and IATF16949 certifications.

FSHY positions itself as a leading domestic provider of current sensing resistor solutions, continuously focused on the design, development, manufacturing, and sales of alloy resistors and shunts. Products are widely used in power supplies, BMS battery management systems, automotive electronics, smart home appliances, industrial automation, power tools, inverters, and cell testing equipment.

II. Complete Product Series Analysis

FSHY's core products are milli-ohm level high-precision alloy resistors and current sensing resistors/shunts. Based on structure, package size, power rating, and process characteristics, the product lines include:

(I) WSM Series—Molded Beam-Welded Alloy Resistors

Part Number Format: WSM + Package Size + Resistance Code + Tolerance Code + Packaging Code

Representative Models:

• WSM1206MR001FT0—1206 package, 1mΩ, 1% tolerance, 2W

• WSM2725FR003FT0—2725 package, 3mΩ, 1% tolerance, 4W

• WSM2817KR005FT0—2817 package, 5mΩ, 1% tolerance, 5W, TCR ±75ppm/℃

• WSMB2512KR100FT0—2512 package, 0.1Ω, 1% tolerance, 2W

Features: Molded structure, SMD package, extremely low resistance (down to 0.0002R), high power density, AEC-Q200 automotive reliability qualified. TCR covers ±20ppm/℃, ±50ppm/℃, ±75ppm/℃ grades.

Applications: Current sensing in automotive electronics, BMS battery management systems, power supply current sensors, inverters.

Advantages: Molded process provides excellent environmental protection for harsh automotive conditions. AEC-Q200 certified for automotive-grade reliability requirements.

Market Positioning: Automotive-grade medium to high power current sensing, core components for NEV BMS and on-board power management.

(II) WSN Series—Bare Die Beam-Welded Alloy Resistors

Part Number Format: WSN + Package Size + Resistance Code + Tolerance Code + Power Code

Representative Models:

• WSN3920FL200JT0—3920 package, 0.2mΩ, 5% tolerance, 5W

• WSN3920FL300JT0—3920 package, 0.3mΩ, 5% tolerance, 5W

• WSN5930ML600FT0—5930 package, 0.6mΩ, 1% tolerance, 7W

• WSN5930ML700FT0—5930 package, 0.7mΩ, 1% tolerance, 7W

Features: Bare die beam-welded structure, electron beam welding process, all-metal construction, ultra-low resistance (down to 0.0002R), high power density. Excellent consistency, high reliability, high stability, strong pulse withstand capability, supports ±0.5% resistance tolerance. Inductance <10nH.

Applications: High-current sensing scenarios including high-power current sensors in power supplies, inverters, cell testing equipment.

Advantages: Bare die structure offers lower thermal resistance and higher power handling. Electron beam welding ensures reliable connection between alloy material and electrodes, reducing contact resistance and thermal EMF. Ultra-low inductance (<10nH) enables excellent performance in high-frequency switching applications.

Market Positioning: High-power, ultra-low resistance current sensing for industrial power supplies, variable frequency drives, and other demanding applications.

(III) WSMP Series—High-Power Molded Alloy Resistors

Part Number Format: WSMP + Package Size + Resistance Code + Tolerance Code

Representative Models:

• WSMP2817KR005JT0—2817 package, 5mΩ, 5% tolerance, 7W

• WSMP2817KR004JT0—2817 package, 4mΩ, 5% tolerance, 7W

• WSMP4527MR005FT0—4527 package, 5mΩ, 1% tolerance, 5W, TCR ±75ppm/℃

• WSMP4527KR010FT0—4527 package, 10mΩ

Features: High-power molded structure, SMD package, extremely low resistance (down to 0.0005R), high power, surge withstand capability. AEC-Q200 automotive reliability qualified.

Applications: Current sensing requiring high power handling, such as automotive power modules, industrial drive power supplies.

Advantages: Higher power rating in same package size (e.g., 2817 package up to 7W), strong surge withstand for applications with current transients.

Market Positioning: High power density current sensing with automotive-grade reliability.

(IV) WSK/WSKN Series—4-Terminal Precision Alloy Resistors

Part Number Format: WSKN + Package Size + Resistance Code + Tolerance Code + Power Code

Representative Models:

• WSKN3820ML200JT0—3820 package, 0.2mΩ, 5% tolerance, 5W

• WSKN3820FR005JT0—3820 package, 5mΩ, 5% tolerance, 5W

• WSKN3820FL600FT0—3820 package, 0.6mΩ, 1% tolerance, 5W

• WSKN4026FR004FT0—4026 package, 4mΩ

Features: 4-terminal (Kelvin) structure, electron beam welding process, pure copper electrodes. All-metal construction, excellent consistency, high reliability, high stability, strong pulse withstand, supports ±0.5% resistance tolerance.

Applications: High-precision current sensing, ideal for微弱 signal measurement such as cell current monitoring in BMS battery management, precision measurement instruments.

Advantages: 4-terminal structure eliminates lead resistance impact on measurement accuracy—the ideal solution for current sensing applications. Pure copper electrodes reduce contact resistance and thermal EMF for improved sensing accuracy.

Market Positioning: High-precision current sensing for精密 measurement and BMS applications demanding极致 accuracy.

(V) CSM Series—Composite Alloy Resistors

Part Number Format: CSM + Package Size + Resistance Code + Tolerance Code

Representative Models:

• CSM1206MR010FT0—1206 package, 10mΩ, 1% tolerance, 1.5W, TCR ±50ppm/℃

• CSM1206MR005FT0—1206 package, 5mΩ, 1% tolerance, 1.5W, TCR ±50ppm/℃

Features: Composite alloy material, SMD package, high power density, low thermal EMF and low TCR, industrial-grade reliability qualified.

Applications: General industrial current sensing for smart home appliances, power tools, industrial control.

Advantages: Composite alloy material provides excellent cost-performance balance. Low TCR (±50ppm/℃) ensures sensing accuracy across wide temperature range.

Market Positioning: Industrial-grade general current sensing with cost-performance focus.

(VI) HYR/HYRF Series—High-Precision Alloy Resistors

Part Number Format: HYR + Power Code + Package Size + Resistance Code + Tolerance Code

Representative Models:

• HYR4W2728R030F—2728 package, 30mΩ, ±1% tolerance, 4W, TCR ±50ppm/℃

• HYR4W2728R040F—2728 package, 40mΩ

• HYRF2512R003FT—2512 package, 3mΩ, ±1% tolerance, 3W

• HYRF5930R001FT—5930 package, 1mΩ, ±1% tolerance, 7W

Features: High-precision alloy resistor, electron beam welded structure, high temperature withstand, inductance <10nH, RoHS compliant. Tolerances cover ±5%, ±2%, ±1%.

Applications: Power supply current sensors for mixed applications, inverters, precision AC/DC power supplies.

Advantages: Combines high precision (±1%), low TCR (as low as ±20ppm/℃), and ultra-low inductance (<10nH) for applications demanding precision and dynamic response.

Market Positioning: High-precision current sensing for high-end power supplies, precision instruments.

(VII) WSL Series—Zero-Ohm/Jumper Resistors

Representative Models:

• WSL12060000ZTA—1206 package, 0Ω, 100A

• WSL25120000ZT0—2512 package, 0Ω, 120A

Features: Zero-ohm SMD alloy resistors serving as high-current jumpers.

Applications: High-current path connections on PCBs.

Market Positioning: High-current jumper solutions.

III. Product Advantages Summary

1. Complete Technology Chain: FSHY possesses the entire R&D and manufacturing chain from alloy material formulation to electron beam welding precision process to component reliability testing—one of the few domestic manufacturers with full-chain autonomous capability in beam-welded alloy current sensing resistors.

2. Ultra-Low Resistance Capability: Resistance values as low as 0.0002Ω (0.2mΩ), industry-leading.

3. Automotive-Grade Certification: Multiple products AEC-Q200 qualified for stringent automotive electronics requirements.

4. Ultra-Low Inductance: Select products with inductance <10nH, ideal for high-frequency switching applications.

5. Extensive Package Options: Covers 1206, 1216, 2512, 2725, 2728, 2817, 3820, 3920, 4026, 4527, 5930, and more.

6. Comprehensive Certifications: ISO9001/14001 and IATF16949 certified for assured quality.

IV. Market Positioning

FSHY positions itself as a domestic mid-to-high-end current sensing resistor manufacturer, serving:

• Automotive Electronics: NEV BMS, on-board power supplies, motor drives

• Power Supply Industry: Switching power supplies, inverters, converters

• Energy Storage: Storage BMS, cell testing equipment

• Industrial Control: Industrial automation, power tools, variable frequency drives

• Smart Home: Appliance current sensing

• Medical Devices: Precision medical equipment current monitoring

With its complete independent technology chain, automotive-grade quality, and competitive cost-performance, FSHY is emerging as a renowned brand in passive component domestic substitution.

V. Recommended Supplier

Shenzhen Shunhai Technology Co., Ltd. is a professional supplier of FSHY resistor products, providing full-series alloy resistors, current sensing resistors, and shunts with technical selection support, sample applications, and volume supply services. For FSHY product technical documentation, samples, or volume procurement, please contact Shenzhen Shunhai Technology Co., Ltd.