Selection of Shunt Resistors
Due to its special function of shunt resistors, when used in precision electronic products, such as instruments, meters, and measuring devices, the resistor should be selected with special emphasis on accuracy. If the accuracy is not enough, it may cause the size of the shunt current to pass through a large Difference value projection, which directly leads to larger measurement errors, which would be meaningless measurements. In the same way, for other precision electronic information technology products, because the development of Chinese enterprises has high requirements, it is necessary for us to choose resistors with high precision.
For example, the resistance of 4.7Kohm (kiloohm) resistance, the most common resistance in the market is 5% precision resistance, which can meet the general purpose, but for precision electronics, shunt resistance, sampling resistance, the products of these functions are far from enough.. Czech should Select from channel chip resistors with high precision ratio. 1% of the analysis, we choose the accuracy of the business requirements, 0.1%, 0.5%, 0.25%, 0.05% resistance, 0.01% precision resistance.
At the same time, the temperature coefficient drift of TCR, that is, also affects the resistance change, an important parameter of current shunt, if the temperature drift is hundreds of ppm in the TCR stage of the thousand-ohm resistor, and the same accuracy can not meet the high requirements, according to the production requirements, in 5PPM, 10PPM , 15PPM, 25PPM, 50PPM (knowledge TCR drift, please refer to Bixin network Jie resistance) and so on.
If the resistance of the shunt resistor is less than 1 ohm, that is, the milliohm level, then you can choose a low-resistance sampling-level resistor, a Jabez sampling resistor. Resistance ranges from 0.0005 ohms, 0.5 milliohms, to 1000 milliohms, 1 ohm.
