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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We can also call it an 'alternator', because it generates alternating current (AC).

我们可以也称之为'发电机'，因为它产生交流电(AC)。

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Inverters and microinverters convert the direct current (DC) power produced by solar panels into alternating current (AC) used in homes and businesses.

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Since 2005, the company has stood out in the fast-moving LED industry with an innovation that allows LEDs to be powered by alternating current, or AC, rather than requiring a transformer that turns AC into direct current.

WSJ: Seoul Semiconductor's LED-Lighted Path