super-low frequency voltmeter

例句：

1. 1.The super-low frequency voltmeterwas used to measure the voltage of thecircuit.
   使用超低频电压表测量电路的电压。
2. 2. The engineer carefully checked the super-low frequency voltmeter before startingthe experiment.
   工程师在开始实验前仔细检查了超低频电压表。
3. 3. The super-low frequency voltmeter was usedto detect any potential faults in theelectrical system.
   超低频电压表被用来检测电气系统中的任何潜在故障。