The effect of low resistance sampling resistor on circuit stability cannot be ignored

Low-resistance sampling resistors are widely used in circuits. Usually, the low-resistance sampling resistors we use are mostly plug-in resistors and chip resistors. At present, alloy sampling resistors have become a hot-selling resistor in the market. Circuit stability is very important. When performing current sampling and voltage sampling, there are many application cases of sampling resistors. For example, the resistors used for current sampling in automobile current detection resistors are generally precision shunt products.

According to Ohm's law, when the current of the sampling resistor flows through the resistor, the voltage across the low-resistance sampling resistor is proportional to the current. When the current passing through the 2W resistor is several hundred mA, this sampling circuit design is relatively successful. . However, if the current reaches 5-30A, the situation is completely different, because the power lost in the low resistance sampling resistor cannot be ignored. We can reduce the power loss by reducing the resistance of the low-resistance sampling resistor, but the voltage across the resistor will also decrease accordingly, so based on the sampling resolution, the resistance of the resistor should not be too low.

Long-term stability of low-value sampling resistors is very important for any sensor. Even after a few years of use, it is desirable to maintain early accuracy. This means that the resistive material must resist corrosion during the life cycle. , and the alloy composition cannot be changed. To make the measuring element meet these requirements, an alloy composed of homogenous composite crystals can be used to achieve the basic thermodynamic state through the production process of annealing and stabilization treatment. The stability of such an alloy can reach ppm/ years, making it usable for standard resistors.

At present, there are many low-resistance sampling resistors on the market, but there are relatively few low-resistance sampling resistors in some high-end fields. For example, in the current detection system BMS of new energy vehicle products, the use of high-precision current sampling resistors is required. At present, many new energy vehicles are constantly developing and producing various types of current detection system BMS, which all require the use of high-precision current sampling resistors, otherwise the high-precision BMS system battery management system design cannot be completed.