Step down transformers provide low voltage AC power for lighting, instruments and other circuits that use alternating current at a lower voltage.

降压变压器低压AC电源提供照明，仪器仪表和其他使用交流电在一个较低的电压的电路。

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Their job is to convert high-voltage alternating current from the mains into low-voltage direct current for mobile phones, laptops, iPods and other electronic gadgets.

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