Four terminal alloy sampling resistor
Four terminal alloy sampling resistor is a key component used for precision current detection, especially widely used in high-precision and high reliability requirements. The table below summarizes its core parameters for your quick understanding.
Core Parameters
| Parameter category | Specific parameter description and typical values/ranges |
|---|---|
| Resistance | The basic characteristic resistance is extremely low, commonly ranging from 0.1m Ω to 500m Ω, and can even be as low as 0.05m Ω. |
| Precision/Tolerance | High precision/tolerance, commonly ± 1% or ± 0.5%, with precision levels up to ± 0.1%. |
| Temperature Coefficient (TCR) | The temperature coefficient (TCR) is very low, indicating that the resistance changes little with temperature. The typical value is within ± 50ppm/℃, and high-performance products can reach ± 20ppm/℃ or even ± 5ppm/℃. |
| Rated Power | Rated Power is related to package size and covers a wide range, from approximately 1W (such as 1206 package) to tens of watts (such as large-sized 3920 and 4527 packages). |
| Package Size Specifications | There are various package size specifications, including standard surface mount packages such as 0603, 0805, 1206, 2512, high-power packages such as 3920, 4527, and four terminal dedicated long electrode packages such as 0508, 0612. |
| Electrical and Structural Characteristics | Four terminal (Kelvin) connection core structure, physical separation of current path and voltage sampling path, can eliminate the influence of lead and contact resistance on measurement accuracy. |
| Parasitic Inductance Design | Products with excellent parasitic inductance design have extremely low parasitic inductance (up to 3nH), which is crucial for accurately capturing transient currents in high-frequency switching circuits such as switching power supplies and motor drives. |
| Alloy Materials | Alloy materials such as manganese copper, constantan, nickel copper, etc. are commonly used for resistors to ensure low resistance, low temperature coefficient, and high stability. |
How do key parameters affect selection
After understanding the parameters, the following points can be focused on in actual selection:
- The trade-off between accuracy and temperature coefficient: determined based on the temperature variation range of your application scenario. For equipment with large temperature differences in the working environment (such as automotive electronics and outdoor energy equipment), low temperature drift (low TCR) is more important than high precision at room temperature.
- The matching of power and packaging: It not only depends on the rated power of the resistor, but also on the actual heat dissipation capacity of the PCB. When space permits, choosing resistors with slightly larger packaging can usually achieve better heat dissipation performance and long-term reliability. It is necessary to evaluate the possible pulse current in the circuit to ensure that the resistor can withstand short-term overload.
- The true value of the "four terminal": The four terminal structure solves the error problem caused by the resistance of the test lead itself when measuring small resistance values. This is essential for precise measurement of current, especially in battery management BMS and power management.
Summary and Application Scenarios
The four terminal alloy sampling resistor provides a solution for achieving precision current sampling through its low resistance value, high precision, low temperature drift, and unique four wire structure.
- New energy vehicles and BMS require extremely high precision and reliability in current sampling, requiring resistors with low TCR, high power, and vehicle grade reliability.
- Industrial control and frequency converter: The environment is complex, requiring resistors to have high vibration resistance and long lifespan.
- Precision medical equipment/testing instruments: Pursuing extreme precision and stability, we will use top-notch products with ± 0.1% accuracy and ± 5ppm/℃ TCR.
- Communication/server power supply: High frequency switching requires resistors with extremely low parasitic inductance.
I hope this information can help you better understand and select four terminal alloy sampling resistors. If you have specific application scenarios (such as approximate working current, voltage, and environment), I can help you further analyze which parameters may need to be prioritized.