王尧君1，2， 刘  冲1， 蒋  慧1
（1. 南华大学电气工程学院，湖南 衡阳 421001； 2. 中国测试技术研究院，四川 成都 610021）
摘  要：为准确测量不同频率的交变电压有效值，介绍两种常用的测量方法——热等效法和公式计算法，并分析各自的特点。分别利用这两种方法搭建测量电路，对不同频率正弦波有效值进行测量。对测量数据进行分析，客观比较两测量电路的精度和频率响应。分析结果表明：热等效法适合测量高频信号的电压有效值，而公式计算法适合测量低频信号的有效值，该结论为不同场合测量有效值的各种应用做出参考。
关键词：电压有效值；热等效法；公式计算法；电压测量
中图分类号：TM131.3；TM933.2；TM930.114；TN431.1    文献标志码：A    文章编号：1674-5124（2013）03-0027-04
Comparison of two RMS-DC measurement methods
WANG Yao-jun1，2， LIU Chong1， JIANG Hui1
（1. School of Electric Engineering，University of South China，Hengyang 421001，China；
2. National Institute of Measurement and Testing Technology，Chengdu 610021，China）
Abstract: In order to accurately measure the alternating voltage RMS （root mean square） value of different frequencies， two commonly used measurement methods （thermal equivalent and formula method） were introduced and their characteristics were analyzed， respectively. Each measuring circuit of these two methods was built to measure the sine waves of different frequencies. According to the analysis of the measurement data， accuracy and frequency response were compared objectively between the two measuring circuits. The results show that thermal equivalent is suitable for measuring RMS voltage of the high-frequency signal and the formula method is suitable for the low-frequency signal. It can be reference for the various applications of RMS measurements in different cases.
Key words: RMS voltage； thermal equivalent； formula method； voltage measurement