王堯君1，2， 劉  沖1， 蔣  慧1
（1. 南華大學電氣工程學院，湖南 衡陽 421001； 2. 中國測試技術研究院，四川 成都 610021）
摘  要：為準確測量不同頻率的交變電壓有效值，介紹兩種常用的測量方法——熱等效法和公式計算法，并分析各自的特點。分別利用這兩種方法搭建測量電路，對不同頻率正弦波有效值進行測量。對測量數據進行分析，客觀比較兩測量電路的精度和頻率響應。分析結果表明：熱等效法適合測量高頻信號的電壓有效值，而公式計算法適合測量低頻信號的有效值，該結論為不同場合測量有效值的各種應用做出參考。
關鍵詞：電壓有效值；熱等效法；公式計算法；電壓測量
中圖分類號：TM131.3；TM933.2；TM930.114；TN431.1    文獻標志碼：A    文章編號：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