This produces a waveform of one polarity operating at a frequency twice that of the mains supply.

经过整流后得到的是一个频率为交流电源两倍的单极波形。

youdao

Numerous types of inverter are available, but not all are suitable for use when feeding power back into the UK mains supply.

许多类型的变换器是通用的，但不是所有的适合使用，当能连回到英国的供应。

youdao

The primary power supply is powered from the mains supply and energizes a lumped coil; the current ranges anywhere from 5 to125 amps.

主要的电力供给是来自市电电源并通过一个集合线圈激发；电流范围从5到125安培。

youdao

The NEA wants government help to get more communities connected to the mains supply to cut fuel poverty.

BBC: Rural struggle without mains gas

We have had no mains supply for over 48 hours.

BBC: Water chaos affects thousands in Northern Ireland

In the 70s when I was away from a mains electricity supply, a 12-volt battery would keep my respirator operating for just 20 minutes.

CNN: 'I lived in an iron lung for seven years'