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【实验指导】新版教科版小学科学四年级下册2.4电路出故障了
1.电路出故障了，我们
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"https:?/??/?mp.weixin.?/?_blank?)可以用电路检测器来检测哪里出了问题。我们也可以用替换法来排除故障，使灯泡亮起来。
2.像铜丝那样可以通过电流的物质，叫导体。铜、铝、铁等各种金属、铅笔芯、人体、大地等都是导体，利用导体可以把电送到人们需要的地方。
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做一个电路检测器的方法：把简易电路中的开关拆除后，就形成了一个电路检测器。
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做一个电路检测器的步骤：
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提示：每次检测前，先将两个检测头互相接触一下，看看小灯泡能否亮起来。
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强调：不能用电路检测器检测家用电器的电路。
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5.电路中的哪一部分出了故障，你是怎么知道的？又是怎么排除的？
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可能出现的故障
检测部位
排除故障的方法
小灯泡坏了
检测小灯泡
更换小灯泡
小灯泡与灯座接触不良
检测小灯泡与灯座的接触之处
将小灯泡重新固定在灯座上，并且使之接触良好。
电池没有电了
检测电池
更换电池
导线断了
检测导线
更换导线
开关接触不良
检测开关
更换开关
精炼反馈
1.电路检测器连接到没故障的地方，小灯泡就会亮；连接到有故障的地方，小灯泡就不会亮。
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A.对
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B.错
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C.不知道
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【答案】A
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2.我们制作的电路检测器可以去检测家用220V的电器电路。
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A.对
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B.错
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C.不知道
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【答案】B
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