一种改进的小电阻测量方法

An improved measuring method for low resistance

为提高小电阻测量精度,通常先将电压信号进行放大后再进行电压采集。目前的放大方法为从低到高逐级放大直至最佳放大状态,由于每次放大后均需要延时等待信号稳定后再采样,导致测量时间延长,从而导致测试速度相对较慢。针对以上存在的问题,提出了一种放大倍数随被测电阻值动态调整且一次性将信号放大到最佳状态的测量方法,在保证测试精度的同时不降低测试速度。该方法对电压进行两次采样,第一次电压采样时放大倍数设置为1,第二次电压采样时根据第一次的采样结果选取最合适的电压放大倍数,进而提高测试速度。同时,通过实验对所提出的方法与逐级放大倍数方法进行了对比。对比结果表明,所提出的方法具有更快的测试速度。

In general,an amplifier is used to improve the measurement accuracy before the voltage signal input into the A/D converter.After the signal is amplified,it is necessary to wait for a period of time before sampling,which will result in longer measurement time.In this paper,a new measuring method that can directly adjust the magnification to the most appropriate amplitude is proposed to solve the problem.Twice sampling will be done:during the first sampling,the magnification is set to one;and during the second sampling,the magnification is changed according to the result of the first sampling.The contrastive analysis between the proposed method and the traditional magnification method is carried out to validate the proposed method.