0欧电阻作用
热度 3已有 955 次阅读2013-4-17 13:55
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0R电阻
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mso-ansi-language:EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">在论坛中看到有人问,
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">0
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">欧电阻作用,依据个人经验,在此总结一下。
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
1,
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EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">在电路中没有任何功能,只是在
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">PCB
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">上为了调试方便或兼容设计等原因;
mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
2,
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">可以做跳线用,如果某段线路不用,直接不贴该电阻即可(不影响外观);
mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
3,
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">在匹配电路参数不确定的时候,以
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">0
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">欧姆代替,实际调试的时候,确定参数,再以具体数值的元件代替;
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
4,
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">想测某部分电路的耗电流的时候,可以去掉
mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">0ohm
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ZH-CN;mso-bidi-language:AR-SA">电阻,接上电流表,这样方便测耗电流;
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
5,
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EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">在布线时
mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">,
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">如果实在布不过去了
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">,
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">也可以加一个
宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN;
mso-bidi-language:AR-SA">0
"Times New Roman";mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;
mso-ansi-language:EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">欧的电阻;
mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
6,
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">在高频信号下,充当电感或电容。(与外部电路特性有关)电感用,主要是解决
mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">EMC
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ZH-CN;mso-bidi-language:AR-SA">问题。如地与地,电源和
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">IC Pin
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">间
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mso-bidi-language:AR-SA">
7,
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EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">单点接地(指保护接地、工作接地、直流接地在设备上相互分开
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">,
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ZH-CN;mso-bidi-language:AR-SA">各自成为独立系统。);
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
8,
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EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">熔丝作用;
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
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EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">什么单点接地:
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA"> 只要是地,最终都要接到一起,然后入大地。如果不接在一起就是
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">"
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ZH-CN;mso-bidi-language:AR-SA">浮地
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mso-bidi-language:AR-SA">"
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mso-ansi-language:EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">,存在压差,容易积累电荷,造成静电。地是参考
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">0
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ZH-CN;mso-bidi-language:AR-SA">电位,所有电压都是参考地得出的,地的标准要一致,故各种地应短接在一起。人们认为大地能够吸收所有电荷,始终维持稳定,是最终的地参考点。虽然有些板子没有接大地,但发电厂是接大地的,板子上的电源最终还是会返回发电厂入地。如果把模拟地和数字地大面积直接相连,会导致互相干扰。不短接又不妥,理由如上有四种方法解决此问题:
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
1
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EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">、用磁珠连接;
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
2
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">、用电容连接;
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
3
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">、用电感连接;
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
4
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EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">、用
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">0
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">欧姆电阻连接。
宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:ZH-CN;
mso-bidi-language:AR-SA">
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA"> 磁珠的等效电路相当于带阻限波器,只对某个频点的噪声有显著抑制作用,使用时需要预先估计噪点频率,以便选用适当型号。对于频率不确定或无法预知的情况,磁珠不合。
mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA"> 电容隔直通交,造成浮地。
mso-fareast-font-family:宋体;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
mso-bidi-font-family:"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:
EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA"> 电感体积大,杂散参数多,不稳定。
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
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EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">0
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">欧电阻相当于很窄的电流通路,能够有效地限制环路电流,使噪声得到抑制。电阻在所有频带上都有衰减作用
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mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">(0
"Times New Roman";mso-font-kerning:1.0pt;mso-ansi-language:EN-US;mso-fareast-language:
ZH-CN;mso-bidi-language:AR-SA">欧电阻也有阻抗
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mso-bidi-language:AR-SA">)
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mso-ansi-language:EN-US;mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA">,这点比磁珠强。