题干

如图所示的光控电路用发光二极管LED模拟路灯,RG为光敏电阻.A为斯密特触发器输入端,在天黑时路灯(发光二极管)会点亮.下列说法正确的是 (   )

A:天黑时,Y处于高电平

B:天黑时,Y处于低电平

C:当R1调大时,天更暗时,灯(发光二极管)点亮

D:当R1调大时,天较亮时,灯(发光二极管)就能点亮

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答案(点此获取答案解析)

B,C

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