SQF series resistors with current limiting and fusing functions, suitable for the Japanese and Korean markets

The South Korean and Japanese electronics industries are continuously raising their requirements for circuit safety.

As industrial automation equipment, power modules, home appliances, and control systems continue to evolve towards higher reliability, the South Korean and Japanese markets are placing higher demands on the safety performance of electronic components. Especially during power startup, abnormal overload, continuous operation, and high-temperature environments, circuit protection capabilities have become a crucial consideration in equipment design.

For engineers, while traditional power resistors can handle current limiting and power dissipation, additional protective components are often required when the system experiences abnormal temperature rise. Achieving more efficient and reliable safety protection within limited space has become a key focus for many equipment manufacturers.

Against this backdrop, thermal fuse cement resistors, which combine current limiting and fusing functions, are gradually becoming an important solution in industrial and consumer electronics.

The SQF series thermal fuse cement resistors integrate wire-wound resistors and thermal fuse protection structures within the same device, simultaneously providing power limiting and overheat protection. According to product data, they are primarily used in circuit board protection and safety control scenarios.

Common applications in the Japanese and Korean markets include:

The SQF series adopts a ceramic flame-retardant shell structure, possessing excellent insulation and moisture resistance, while combining a thermal fuse mechanism to achieve circuit protection.

Its design features are mainly reflected in the following aspects:

• Flame-retardant Structure Design The product uses a ceramic shell with flame-retardant properties, which can reduce the risk of combustion under abnormal load conditions. Test results show that the product meets the non-combustible requirements.
• Precise Thermal Blowout Protection The SQF series offers multiple operating temperatures, including 132℃, 145℃, and 185℃, to match the design requirements of different equipment.
• Excellent Surge Resistance Facing starting current and transient impacts, the product can withstand surge loads of up to 10 times the rated power for 5 seconds, helping to improve system stability under complex operating conditions.
• High Insulation Performance The product's insulation resistance reaches over 1000MΩ (DC500V) and has passed the AC1000V withstand voltage test, meeting the electrical safety requirements of industrial equipment and power systems.

For the long-term reliability concerns commonly raised by Japanese and Korean customers, the SQF series offers clearly defined parameter support:

• Resistance Range: 0.1Ω～50KΩ
• Resistance Accuracy: ±5%
• Thermal Blowout Temperature: 132℃ / 145℃ / 185℃
• Rated Current: 3A / 5A / 10A
• Insulation Resistance: ≥1000MΩ (DC500V)
• Load Life Test: 1000 hours at 70℃
• Damp Heat Life Test: 500 hours at 40℃ and 95%RH
• Complies with IEC 60115-1 and JIS C 5201-1 standards

These parameters enable it to meet the comprehensive requirements of stability and safety in industrial control, power supply equipment, and electronic manufacturing.

As the Japanese and Korean electronics manufacturing industries continue to demand higher levels of equipment reliability, safety, and long-term operational stability, protective resistors with both current limiting and thermal blowing functions are attracting increasing attention from engineers.

The SQF series of thermally fusible cement resistors offers a solution that balances safety and functionality for circuit board protection, power management, and industrial control systems. Featuring a flame-retardant ceramic structure, selectable fusing temperatures from 132°C to 185°C, surge protection up to 10 times the rated power, and insulation performance exceeding 1000MΩ, these products are becoming an attractive option for equipment manufacturers looking to optimize circuit protection design and reduce the need for additional protection components.