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How a Light Switch Works
电灯开关如何工作
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A light switch controls electricity flow in your home.电灯开关控制家中电流的通断。
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When you flip it up, the circuit closes.向上拨动时，电路闭合。
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Electric current then travels to the light bulb.电流随即流向灯泡。
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The bulb turns on and gives bright light.灯泡亮起，发出明亮光线。
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Flipping it down opens the circuit again.向下拨动则再次断开电路。
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Current stops, and the light goes off.电流停止，灯熄灭。
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No wires are exposed — it is very safe.没有外露电线，非常安全。
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This simple device uses basic engineering.这个简单装置运用了基础工程原理。