high-low voltmeter

例句：

1. 1. The high-low voltmeter showed that the power supply was stable.
   高低电压表显示电源稳定。
2. 2. The engineer used a high-low voltmeter to measure the voltage across the circuit.
   工程师使用高低电压表测量电路两端的电压。
3. 3. The high-low voltmeter was used to monitor the electrical current in the circuit.
   高低电压表用于监测电路中的电流。