“半偏法测内阻”的误差分析和实验方案选择

Error analysis and improvement on the measurement of internal resistance of a galvanometer for half-scale method

“电表改装和校验”实验中分压电阻和分流电阻大小的设取与电流表的内阻有关.文章详细分析用半偏法测电流表内阻时发生的实验误差,针对采用传统分立仪器和采用天煌教仪公司的“TKDG-1型电表改装与校准实验仪”,分别就实验方案选择作了全面分析.结果发现,在使用后者做该实验时,如果不对实验方法进行仔细推敲,测得的电流表内阻与实际情况会有很大偏差,给后续表头改装和校验带来困难,影响实验的有效性.

To make a choice of a resistor as a multiplier or a shunt needed in the experiment named of ＂convert the galvanometer to ammeter and voltmeter and calibrate them＂ depended on the internal resistance of the galvanometer. In this paper, we analyze the cause of experimental errors due to half-scale method with general instruments or with the ＂TKDG-1 galvanometer convert and calibrate system＂ made in Tianhuang Co in detail. We found that errors existed in the measurement of internal resistance of the galvanometer due to this instrument if we didn＇t choose the method for experiment carefully in advance. Thus there would be many difficulties in the experiments and the whole results of the experiment would be meaningless.