电压组合 meaning in English

voltage combination

Measurement at each additional frequency voltage combination
每一额外频率电压组合的测量
Voltage measurement at each additional frequency voltage combination
每一额外频率电压组合的电压测量。
Calibration of precision ac voltmeter at one frequency voltage combination by ac - dc transfer
以交直流转换方法按一频率电压组合校正精密交流电压计
Calibration at each additional frequency voltage combination by ac - dc transfer , for the same equipment
以交直流转换方法按每一额外频率电压组合校正同一仪器