📄 电子基础电阻.htm
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<IMG height=29 src="电子基础电阻.files/resist11.gif" width=128 border=0
v:shapes="_x0000_i1035">式中:R1、R2分别是电压为U1和U2时的电阻值</SPAN></SPAN></P>
<P><SPAN style="COLOR: green; FONT-FAMILY: 宋体; Times: ">噪声电动势:</SPAN><SPAN
style="COLOR: black; FONT-FAMILY: 宋体">电阻器的噪声电动势在一般电路中可以不考虑,但在弱信号系统中不可忽视。<SPAN><BR>线绕电阻器的噪声只习作定于热噪声(分子扰动引起)仅与阻值、温度和外界电压的频带有关。薄膜电阻除了热噪声外,还有电流噪声,这种噪声近似地与外加电压成正比。
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<P><SPAN style="COLOR: green; FONT-FAMILY: 宋体; Times: ">高频特性:</SPAN><SPAN
style="COLOR: black; FONT-FAMILY: 宋体">电阻器使用在高频条件下,要考虑其固定有电感和固有电容的影响。这时,电阻器变为一个直流电阻(<SPAN>R0)与分布电感串联,然后再与分布电容并联的等效电路,非线绕电阻器的LR=0.01-0.05微亨,CR=0.1-5皮法,线绕电阻器的LR达几十微亨,CR达几十皮法,即使是无感绕法的线绕电阻器,LR仍有零点几微亨。
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href="http://league.ysu.edu.cn/wuxie/dzjc/dz.asp#top">返回顶部</A></P><SPAN></SPAN>
<P align=left><SPAN class=style1>3. 命名方法<A
name=3></A></SPAN><BR></FONT><SPAN
style="COLOR: black; FONT-FAMILY: 宋体">根据部颁标准(<SPAN>SJ-73)规定,电阻器、电位器的命名由下列四部分组成:第一部分(主称);第二部分:(材料);第三部分(分类特征);第四部分(序号)。它们的型号及意义见下表。</SPAN></SPAN><SPAN>
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<P><SPAN style="COLOR: fuchsia; FONT-FAMILY: 宋体; Times: ">表</SPAN><SPAN
style="COLOR: fuchsia">6</SPAN><SPAN
style="COLOR: fuchsia; FONT-FAMILY: 宋体; Times: "> 电阻器的型号命名法</SPAN><SPAN
style="COLOR: fuchsia"> </SPAN></P>
<TABLE class=MsoNormalTable borderColor=#ff9900 cellSpacing=0
cellPadding=0 width=575 align=center border=1>
<TBODY>
<TR>
<TD vAlign=top colSpan=2>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">第一部分</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top colSpan=2>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">第二部分</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top colSpan=2>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">第三部分</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top width=105>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">第四部分</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD></TR>
<TR>
<TD vAlign=top colSpan=2>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">用字母表示主称</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top colSpan=2>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">用字母表示材料</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top colSpan=2>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">用数字或字母表示特征</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top width=105>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">序号</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD></TR>
<TR>
<TD vAlign=top width=42>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">符号</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top width=69>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">意义</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top width=58>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">符号</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top width=90>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">意义</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top width=69>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">符号</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top width=126>
<P style="TEXT-ALIGN: center" align=center><SPAN
style="FONT-FAMILY: 楷体_GB2312">意义</SPAN><SPAN
style="COLOR: #3366ff"> </SPAN></P></TD>
<TD vAlign=top width=105> </TD></TR>
<TR>
<TD vAlign=top width=42>
<P style="TEXT-ALIGN: center" align=center><SPAN>R </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>RP </SPAN></P></TD>
<TD vAlign=top width=69>
<P style="TEXT-ALIGN: center" align=center><SPAN>电阻器</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>电位器</SPAN></P></TD>
<TD vAlign=top width=58>
<P style="TEXT-ALIGN: center" align=center><SPAN>T </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>P </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>U </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>C </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>H </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>I </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>J </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>Y </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>S </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>N </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>X </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>R </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>G </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>M </SPAN></P></TD>
<TD vAlign=top width=90>
<P style="TEXT-ALIGN: center" align=center><SPAN>碳膜</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>金属膜</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>合成膜</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>沉积膜</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>合成膜</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>玻璃釉膜</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>金属膜</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>氧化膜</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>有机实芯</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>无机实芯</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>线绕</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>热敏</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>光敏</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>压敏</SPAN></P></TD>
<TD vAlign=top width=69>
<P style="TEXT-ALIGN: center" align=center><SPAN>1,<SPAN
style="FONT: 7pt 'Times New Roman'"> </SPAN></SPAN><SPAN>2
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>3 </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>4 </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>7 </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>8 </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>9 </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>G </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>T </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>X </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>L </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>W </SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>D </SPAN></P></TD>
<TD vAlign=top width=126>
<P style="TEXT-ALIGN: center" align=center><SPAN>普通</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>超高频</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>高阻</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>高温</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>精密</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center"
align=center><SPAN>电阻器</SPAN><SPAN>-</SPAN><SPAN>高压</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center"
align=center><SPAN>电位器</SPAN><SPAN>-</SPAN><SPAN>特殊函数</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>特殊</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>高功率</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>可调</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>小型</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>测量用</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>微调</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>多圈</SPAN></P></TD>
<TD vAlign=top width=105>
<P style="TEXT-ALIGN: center" align=center><SPAN>包括:</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>额定功率</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>阻值</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center" align=center><SPAN>允许误差</SPAN><SPAN>
</SPAN></P>
<P style="TEXT-ALIGN: center"
align=center><SPAN>精度等级</SPAN></P></TD></TR></TBODY></TABLE>
<P><SPAN>示例:</SPAN><SPAN>RJ71-0.125</SPAN><SPAN>-</SPAN><SPAN>5.1kI</SPAN><SPAN>型的命名含义:</SPAN><SPAN>R</SPAN><SPAN>电阻器</SPAN><SPAN>-J</SPAN><SPAN>金属膜</SPAN><SPAN>-7</SPAN><SPAN>精密</SPAN><SPAN>-1</SPAN><SPAN>序号</SPAN><SPAN>-0.125</SPAN><SPAN>额定功率</SPAN><SPAN>-5.1k</SPAN><SPAN>标称阻值</SPAN><SPAN>-I</SPAN><SPAN>误差</SPAN><SPAN>5%</SPAN><SPAN>。</SPAN></P>
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</SPAN></P>
<P><SPAN class=style1>4.选用常识<A name=4></A>
</SPAN><BR><SPAN>根据电子设备的技术指标和电路的具体要求选用电阻的型号和误差等级;额定功率应大于实际消耗功率的</SPAN><SPAN>1.5-2</SPAN><SPAN>倍;电阻装接前要测量核对,尤其是要求较高时,还要人工老化处理,提高稳定性;根据电路工作频率选择不同类型的电阻。</SPAN><SPAN>
</SPAN></P>
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<P class=titleb>二、检测方法与经验<A name=#5></A></P><STRONG>1.
固定电阻器的检测</STRONG><BR><SPAN>将两表笔</SPAN><SPAN>(</SPAN><SPAN>不分正负</SPAN><SPAN>)</SPAN><SPAN>分别与电阻的两端引脚相接即可测出实际电阻值。为了提高测量精度,应根据被测电阻标称值的大小来选择量程。由于欧姆挡刻度的非线性关系,它的中间一段分度较为精细,因此应使指针指示值尽可能落到刻度的中段位置,即全刻度起始的</SPAN><SPAN>20</SPAN><SPAN>%~</SPAN><SPAN>80</SPAN><SPAN>%弧度范围内,以使测量更准确。根据电阻误差等级不同。读数与标称阻值之间分别允许有</SPAN><SPAN>±5</SPAN><SPAN>%、</SPAN><SPAN>±10</SPAN><SPAN>%或</SPAN><SPAN>±20</SPAN><SPAN>%的误差。如不相符,超出误差范围,则说明该电阻值变值了。</SPAN><SPAN>B
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