电子(zi)元器件(jian)-常(chang)用(yong)电子(zi)元器件(jian)基础知(zhi)识大全-KIA 电子(zi)元器件(jian)
信息来(lai)源(yuan):本站 日期:2018-01-04
简称电(dian)阻,是指具有一(yi)定技术性能的在(zai)电(dian)路(lu)中(zhong)专起(qi)电(dian)阻作(zuo)(zuo)用的元件,可用来调节(jie)电(dian)路(lu)中(zhong)的电(dian)流和电(dian)压,或者作(zuo)(zuo)为电(dian)路(lu)中(zhong)的负载(zai)。
a、 阻(zu)值(zhi):指(zhi)电阻(zu)的数值(zhi)大小。0Ω—几百MΩ
b、 耗散(san)功率(lv):指电阻长期工作时所能承受(shou)(消耗)的最大功率(lv)。
电阻常用(yong)的(de)材(cai)料有碳膜(mo)(mo)、金属(shu)膜(mo)(mo)、金属(shu)氧化膜(mo)(mo)、线(xian)绕、水(shui)泥(陶瓷)线(xian)绕半导体等材(cai)料。
①固定电阻:指电阻值固定不(bu)变的电阻
②微调电阻:指电(dian)阻(zu)值(zhi)可以微调的电(dian)阻(zu)
③可调电(dian)阻:俗称电位器,指(zhi)电阻(zu)(zu)值(zhi)连续可调的电阻(zu)(zu)
④热敏(min)电阻(zu):指电阻值随着(zhe)温度变(bian)化而(er)变(bian)化的电阻
a、 正(zheng)温度系(xi)数热敏(min)电(dian)阻:指电(dian)阻值随(sui)温度升高而(er)增(zeng)大的电(dian)阻(PTC)
b、 负温度系数热敏(min)电阻:指电阻值随温度升高(gao)而减小(xiao)的电阻
⑤压敏电阻:指电阻(zu)值随(sui)着电压的(de)变化而变化的(de)电阻(zu)。
⑥湿敏电阻:指(zhi)电(dian)阻(zu)值随着温度变(bian)化而变(bian)化的电(dian)阻(zu)
⑦光敏(min)电阻:指电阻值随着温度变化而变化的电阻
⑧电阻的功率(lv)表(biao)示法:一般大功(gong)(gong)率(lv)(lv)(lv)(3W以上)电阻均(jun)在电阻外壳上标明(ming)其功(gong)(gong)率(lv)(lv)(lv)值(zhi),如(ru):3W、5W、7W、10W、20W、30W等,而小(xiao)(xiao)功(gong)(gong)率(lv)(lv)(lv)(3W以下)则(ze)部分标明(ming)功(gong)(gong)率(lv)(lv)(lv),(如(ru):3W、2W、1W、等),不(bu)标明(ming)功(gong)(gong)率(lv)(lv)(lv)的(de)(de)则(ze)多为(wei)功(gong)(gong)率(lv)(lv)(lv)1W以下的(de)(de)小(xiao)(xiao)功(gong)(gong)率(lv)(lv)(lv)电阻,对于实际使用(yong)(yong)中(zhong),可(ke)用(yong)(yong)功(gong)(gong)率(lv)(lv)(lv)大的(de)(de)电阻代替功(gong)(gong)率(lv)(lv)(lv)小(xiao)(xiao)的(de)(de)电阻,反之则(ze)不(bu)能代替,若没(mei)有(you)知道电阻功(gong)(gong)率(lv)(lv)(lv)大小(xiao)(xiao)时,在实际应用(yong)(yong)中(zhong)可(ke)用(yong)(yong)电阻体积相同或(huo)稍大的(de)(de)来代替。
①直接(jie)标明(ming)电阻的数值和单位,如:1.5 Ω 、160Ω 、1Ω 等。
②直接标明电阻的数值而把单位(wei)“Ω ”省(sheng)去,如:100即100Ω 、1 即1Ω 、22M即22MΩ。
③用几X几表(biao)示(shi)几点几Ω ,如:4Ω7、9Ω1即(ji)为9.1Ω 、8M2即(ji)8.2MΩ 等。
有些用几R几 代表几点几Ω ,如:1R5即1.5Ω 、3R9即3.9Ω 等。
④电阻值后面有其它英文字母(mu)(如:J、K、M等)或罗马数字(Ⅰ、Ⅱ、Ⅲ)或正负(fu)百分之几(ji)(如:±5%,±10%,±20%)的则表示该(gai)电阻的误差(cha)等级。
⑤数码表示方法(fa)(片状(zhuang)电(dian)阻及部分微调(diao)电(dian)阻和电(dian)位(wei)器(qi)用此法(fa))
用(yong)三(san)位数(shu)字表(biao)示,第一、二位表(biao)示有效(xiao)数(shu),第三(san)位数(shu)表(biao)示倍乘数(shu)(1为101 ,2为 102 ,3为 103 ,4为104 ,……8为 108 ,但9为 100 )把有效(xiao)数(shu)乘以倍乘数(shu)即电阻值。(单(dan)位:Ω)
⑥色(se)环(huan)表示法:
用(yong)色(se)环表(biao)示电(dian)阻(zu)和(he)误差(cha)的(de)电(dian)阻(zu)叫色(se)环电(dian)阻(zu)
①四色环(huan)电阻(为(wei)普(pu)通电阻,应用最多 )
第一、二色(se)(se)环表(biao)示有效数(shu),第三色(se)(se)环表(biao)示倍乘(cheng)数(shu),第四色(se)(se)环表(biao)示误差,(注(zhu):此色(se)(se)环多(duo)为(wei)金,银色(se)(se)或其他(ta)色(se)(se)环远(yuan)些)把有效数(shu)乘(cheng)以倍乘(cheng)数(shu),即为(wei)该电(dian)阻的电(dian)阻值(zhi)(单(dan)位为(wei)Ω )
▲由于(yu)电(dian)阻(zu)值有制(zhi)造误差(cha),万用(yong)表有测量(liang)误差(cha),人的(de)(de)(de)眼力也有误差(cha),故用(yong)万用(yong)表测量(liang)电(dian)阻(zu)值时有一(yi)定的(de)(de)(de)误差(cha)是允许的(de)(de)(de),误差(cha)在(zai) 以(yi)内均视为正常。
▲用高阻(zu)(zu)档(dang)(dang)(RX10K档(dang)(dang)或1K档(dang)(dang))测(ce)试大阻(zu)(zu)值(几(ji)十KΩ以上(shang))的电阻(zu)(zu)时,而导(dao)致读数明显变(bian)小测(ce)量误(wu)差(cha)增大。
▲对于(yu)四色环(huan)电(dian)阻(zu):前(qian)面(mian)再(zai)个(ge)色环(huan)表示有(you)效(xiao)数(shu)(shu)(shu),即(ji)为该电(dian)阻(zu)数(shu)(shu)(shu)值(zhi)的(de)前(qian)两(liang)位(wei),而倍(bei)乘数(shu)(shu)(shu)即(ji)为阻(zu)值(zhi)的(de)倍(bei)数(shu)(shu)(shu),故把(ba)前(qian)两(liang)位(wei)色环(huan)的(de)有(you)效(xiao)数(shu)(shu)(shu)照(zhao)读(写(xie))下(xia)来,再(zai)乘以倍(bei)乘数(shu)(shu)(shu)即(ji)其电(dian)阻(zu)值(zhi)。
▲练习时可(ke)把色(se)环(huan)电(dian)阻(zu)的(de)阻(zu)值(zhi)(zhi)根据(ju)色(se)环(huan)读(du)数出来,再用万(wan)用表(biao)电(dian)阻(zu)档测(ce)试,若测(ce)试值(zhi)(zhi)与自(zi)己(ji)读(du)出值(zhi)(zhi)基(ji)本(ben)相(xiang)同(误差 ),则(ze)你看色(se)环(huan)基(ji)本(ben)准确,若测(ce)量值(zhi)(zhi)与读(du)出值(zhi)(zhi)相(xiang)差太大,则(ze)可(ke)能(neng)某些(xie)色(se)环(huan)的(de)颜(yan)色(se)看错,应该重(zhong)新再测(ce)试再看,直至准确为止。
▲阻(zu)值(zhi)(zhi)小要用低(di)阻(zu)档(dang)(X10或X1)测试而(er)阻(zu)值(zhi)(zhi)大(da)要用高(gao)阻(zu)档(dang)(X10K或X1K)测试,阻(zu)值(zhi)(zhi)不大(da)不小(中等)可用中阻(zu)档(dang)位(如:X1K、X100、X10等)测试,但表针指在接近(jin)刻度中向左右位置(zhi),此时,不但容易看清读数(shu)而(er)且(qie)读数(shu)最准(zhun)确(que)。
▲快速读出四色环电(dian)阻(zu)
第三(san)色(se)环 |
电(dian)阻(zu)值(zhi) |
例 |
第(di)三色环 |
电阻(zu)值 |
例(li) |
银 |
零点几 |
棕灰银金 |
红 |
几(ji)点(dian)几(ji)K |
绿(lv)棕红金 |
金 |
几(ji)点几(ji) |
红红金(jin)(jin)金(jin)(jin) | 橙 |
几十几 K |
橙橙橙金 |
黑 |
几十(shi)几 |
棕黑(hei)黑(hei)金 |
黄 |
几百(bai)几 K |
黄(huang)紫黄(huang)金(jin) |
棕(zong) |
几百几 |
红紫棕金 |
绿 |
几点几M |
棕绿(lv)绿(lv)金(jin) |
蓝(lan) |
几十几 |
橙白蓝(lan)银 |
|
|
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②五色环电阻(为精密电(dian)阻,多(duo)用在仪器仪表或(huo)要求(qiu)高(gao)的电(dian)路中使用)
第一(yi)、二(er)、三色(se)环(huan)(huan)(huan)为(wei)有效数,第四色(se)环(huan)(huan)(huan)表示(shi)倍乘(cheng)数,第五色(se)环(huan)(huan)(huan)表示(shi)误(wu)差(注:此色(se)环(huan)(huan)(huan)多(duo)为(wei)金、银色(se)或离其它色(se)环(huan)(huan)(huan)远(yuan)些)把(ba)有效数乘(cheng)以(yi)倍乘(cheng)数即为(wei)该电(dian)阻(zu)阻(zu)值(单位:Ω )
①对于普通固定电(dian)(dian)阻(zu)(zu)用万用表电(dian)(dian)阻(zu)(zu)档测试(shi)其电(dian)(dian)阻(zu)(zu)值(zhi)(zhi)时(shi)应与电(dian)(dian)阻(zu)(zu)的(de)标称(cheng)值(zhi)(zhi)(即(ji)电(dian)(dian)阻(zu)(zu)上标明的(de)阻(zu)(zu)值(zhi)(zhi))基本相同(误差<±20%)为(wei)正常(chang)。若阻(zu)(zu)值(zhi)(zhi)相差过(guo)大(da)(即(ji)误差为(wei)>±20%)则(ze)(ze)该电(dian)(dian)阻(zu)(zu)已(yi)变(bian)(bian)值(zhi)(zhi)(即(ji)变(bian)(bian)大(da)或(huo)变(bian)(bian)小,以阻(zu)(zu)值(zhi)(zhi)变(bian)(bian)大(da)居多,而阻(zu)(zu)值(zhi)(zhi)变(bian)(bian)小则(ze)(ze)少(shao)(shao)见)而不能(neng)使用,若阻(zu)(zu)值(zhi)(zhi)变(bian)(bian)为(wei)无穷大(da)(∞)则(ze)(ze)该电(dian)(dian)阻(zu)(zu)已(yi)开(kai)路(lu)损(sun)坏,若阻(zu)(zu)值(zhi)(zhi)变(bian)(bian)为(wei)零(极(ji)少(shao)(shao)见),则(ze)(ze)该电(dian)(dian)阻(zu)(zu)已(yi)短路(lu)损(sun)坏。
②对于微调电(dian)(dian)(dian)阻(zu)(zu)(又叫(jiao)微调电(dian)(dian)(dian)位(wei)器(qi))和(he)可调电(dian)(dian)(dian)阻(zu)(zu)(又叫(jiao)电(dian)(dian)(dian)位(wei)器(qi))用(yong)万用(yong)表电(dian)(dian)(dian)阻(zu)(zu)档测试(shi)其两端(duan)电(dian)(dian)(dian)阻(zu)(zu)值(zhi)应与(yu)其标(biao)(biao)称值(zhi)基(ji)本相同(误差<±20%)为(wei)正常,否则(ze)该电(dian)(dian)(dian)位(wei)器(qi)不(bu)良或损(sun)坏。同时测试(shi)电(dian)(dian)(dian)位(wei)器(qi)中(zhong)心头(中(zhong)间引脚(jiao))与(yu)任一(yi)端(duan)之间的(de)电(dian)(dian)(dian)阻(zu)(zu)值(zhi)应在零至标(biao)(biao)称值(zhi)之间连续可微调为(wei)正常,否则(ze)该电(dian)(dian)(dian)位(wei)器(qi)不(bu)良或损(sun)坏。
③对于正温(wen)(wen)度系热敏电(dian)(dian)阻(zu)(PTC),常温(wen)(wen)下(xia)其电(dian)(dian)阻(zu)值(zhi)应为(wei)几十(shi)左(zuo)右为(wei)正常,若(ruo)(ruo)电(dian)(dian)阻(zu)值(zhi)过大则(ze)内部接触不良,若(ruo)(ruo)电(dian)(dian)阻(zu)为(wei)无(wu)穷大,则(ze)已开路(lu)损坏,若(ruo)(ruo)电(dian)(dian)阻(zu)值(zhi)基(ji)本(ben)为(wei)零,则(ze)已短路(lu)损坏,同时该电(dian)(dian)阻(zu)通电(dian)(dian)加(jia)热时其阻(zu)值(zhi)会变得如(ru)大(几百(bai)KΩ 以上)为(wei)正常。
④对于(yu)负温度(du)系数(shu)(shu)热敏电(dian)(dian)(dian)阻(zu)(zu)(zu),常(chang)温下(xia)测试其(qi)(qi)电(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)(zhi)应(ying)与(yu)其(qi)(qi)标称值(zhi)(zhi)基本(ben)相同(tong)(误差(cha))为(wei)正常(chang)。若电(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)(zhi)相差(cha)过大,则该(gai)(gai)电(dian)(dian)(dian)阻(zu)(zu)(zu)不良或损坏(huai),若电(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)(zhi)变为(wei)无穷大,则该(gai)(gai)电(dian)(dian)(dian)阻(zu)(zu)(zu)已开路损坏(huai)。同(tong)时该(gai)(gai)电(dian)(dian)(dian)阻(zu)(zu)(zu)温度(du)越(yue)高(gao)阻(zu)(zu)(zu)值(zhi)(zhi)越(yue)小,而温度(du)越(yue)低阻(zu)(zu)(zu)值(zhi)(zhi)变得越(yue)大为(wei)正常(chang)。否则该(gai)(gai)负温度(du)系数(shu)(shu)热敏电(dian)(dian)(dian)阻(zu)(zu)(zu)不良或损坏(huai)。
⑤对于(yu)压(ya)(ya)敏电(dian)(dian)阻(zu)(zu)(zu)器,由于(yu)其工作电(dian)(dian)压(ya)(ya)较高(几十V以上)故(gu)用万用表电(dian)(dian)阻(zu)(zu)(zu)档(dang)测试时其电(dian)(dian)阻(zu)(zu)(zu)值应为无(wu)穷大为正(zheng)常(因表内电(dian)(dian)池电(dian)(dian)压(ya)(ya)较低)否则(ze)该压(ya)(ya)敏电(dian)(dian)阻(zu)(zu)(zu)不良或损(sun)坏,压(ya)(ya)敏电(dian)(dian)阻(zu)(zu)(zu)在某(mou)额(e)定电(dian)(dian)压(ya)(ya)以下时,阻(zu)(zu)(zu)值均很大(一般为无(wu)穷大,只(zhi)有大到或超过其额(e)定电(dian)(dian)压(ya)(ya)时其阻(zu)(zu)(zu)值才(cai)稳剧减少。
⑥对湿敏电阻(zu),在(zai)空气干燥(zao)条件(jian)下(xia)(xia)测试其(qi)电阻(zu)值应减少(几十(shi)KΩ左(zuo)右);而(er)当没较强光(guang)线照射时其(qi)阻(zu)值则变得(de)较小(几十(shi)Ω以下(xia)(xia))为正常(chang)。否(fou)则该(gai)光(guang)敏电阻(zu)不良或损坏。
①对(dui)于薄膜(如碳膜、金(jin)属膜等(deng))材料的固(gu)定电阻,若损坏时则(ze)不能进行维修,只(zhi)能要更(geng)换解(jie)决。
②对于线绕电阻,多发(fa)生开(kai)路性故(gu)障,此时为电阻丝在(zai)某一位置烧断引起,可能断处焊接好后还(hai)可以(yi)继续使用(yong),若为水(shui)泥(线绕)电阻,则打开(kai)外壳查找烧断处并修补好后,再用(yong)水(shui)泥封装凉(liang)干即可使用(yong),当然最好还(hai)是换新解决为好。
③对于(yu)微(wei)调电阻(zu),容易因为(wei)使用(yong)中间滑动触片与碳膜因氧化而接触不良的故障,此(ci)时用(yong)电位器清洗(xi)剂清洗(xi)解决(jue),清洗(xi)无效只(zhi)能更换解决(jue)。
④对(dui)于电位器(qi),容(rong)易发生碳膜磨损而使中(zhong)间滑(hua)动片(中(zhong)心(xin)抽头)接触不良的故(gu)障,此(ci)时可调整中(zhong)心(xin)滑(hua)动片与(yu)碳膜之间位(wei)置或用电位(wei)器清(qing)洗剂(ji)清(qing)洗解决。
⑤对于正(zheng)温度系数热(re)敏电阻(zu)(PTC),最易发生电(dian)阻与压片(pian)之间的(de)(de)接触(chu)不良的(de)(de)故障,此(ci)时可调整压片(pian)及清(qing)洗修复,若电(dian)阻体(ti)已(yi)经碎(sui),则不能修复,只能更换。
⑥对(dui)于负温度(du)系数热敏(min)电阻,若损坏则不能修复只能换新(xin)。
⑦对(dui)于压敏电阻及(ji)光敏电阻,若损坏(huai)则不能(neng)修复(fu)只能(neng)换新。
⑧对于湿敏电阻,若损(sun)坏时一般只有(you)更换(huan)解决(jue),而难以修复,但对于录(lu)象机、摄(she)象机(DV)等的湿敏电阻损(sun)坏而没有(you)器件更换(huan)时,在应(ying)急情况下可用一个2千(qian)欧(ou)左右(you)的固定电阻代换(huan)解决(jue),此时将失去潮湿检测功能。
简称(cheng)电(dian)容,由两(liang)(liang)片(pian)或两(liang)(liang)组平衡金属板(ban)中(zhong)间一(yi)层电(dian)介(jie)质(绝缘层)构成,是一(yi)种可以储存(cun)电(dian)荷(he)的器(qi)件,具有充放电(dian)的特性。
常见的有空气、陶瓷、云母、涤纶、聚(ju)丙(bing)烯、铝、银等(deng),电解质等(deng)电介质材料(liao)。
①容量:指储存电荷能(neng)力大小的(de)量。
容量(liang)的(de)(de)基本(ben)单(dan)位(wei)(wei)是法(fa)拉,简(jian)称法(fa)(F),常用单(dan)位(wei)(wei)的(de)(de)毫法(fa)(mF)、微(wei)法(fa)(uF)、毫微(wei)法(fa)即(ji)纳法(fa)(nF)、微(wei)微(wei)法(fa)即(ji)皮法(fa)(pF)等。
②耐压:指电(dian)容长期工作时所(suo)能承受的电(dian)压(ya) 耐(nai)压(ya):几V——几KV
①固定无极性电容
指电容量固(gu)定(ding)不(bu)变无极性电容,如(ru):陶瓷(瓷介(jie))电容、云母电容、薄膜电容(如(ru):涤纶、聚丙(bing)烯等(deng)电容)
②微调(diao)(无(wu)极(ji)性)电(dian)容
指电(dian)(dian)容(rong)量可(ke)微调的无极(ji)性电(dian)(dian)容(rong)。(注:微调电(dian)(dian)容(rong)均为无极(ji)性电(dian)(dian)容(rong) )。如:空气陶瓷(ci)、薄(bo)膜(mo)等微调电(dian)(dian)容(rong)。
③可调电容
指电(dian)(dian)容(rong)量(liang)连(lian)(lian)(lian)续可(ke)调(diao)(可(ke)变)的无极(ji)性(xing)电(dian)(dian)容(rong)(注:可(ke)调(diao)电(dian)(dian)容(rong)均为无极(ji)性(xing)电(dian)(dian)容(rong))。如(ru):空气、薄膜(mo)等可(ke)调(diao)电(dian)(dian)容(rong)。常见(jian)的有单(dan)连(lian)(lian)(lian)、双连(lian)(lian)(lian)、四连(lian)(lian)(lian)可(ke)调(diao)(可(ke)变)电(dian)(dian)容(rong)。
④电解(jie)电容(rong)
指(zhi)采用(yong)铝、钽、铌等电(dian)解(jie)(jie)质作(zuo)电(dian)介质的电(dian)容称为电(dian)解(jie)(jie)电(dian)容,电(dian)解(jie)(jie)电(dian)容大多数为有极性电(dian)容。
注(zhu):电(dian)解电(dian)容(rong)(rong)没有微(wei)调(diao)与可调(diao)结(jie)构,全部为容(rong)(rong)量固定的电(dian)容(rong)(rong)。
①直接标明耐压数值和单位。如:(6V、25V、50V、100V等)
(注:电(dian)解(jie)电(dian)容一般采用此法,其它电(dian)容一般较少用)
②直接标明(ming)耐压(ya)数值(zhi)而将单(dan)位(V)省(sheng)去。如:25即25V、63即63V、100即100V等
③用数(shu)字(zi)与字(zi)母表(biao)示(shi)耐压值,由(you)一(yi)(yi)位数(shu)字(zi)(zi)和一(yi)(yi)个字(zi)(zi)母组成,数(shu)字(zi)(zi)表(biao)示耐压10的倍(bei)乘数(shu),字(zi)(zi)母表(biao)示耐压的有效(xiao)数(shu),将(jiang)有效(xiao)数(shu)乘以倍(bei)乘数(shu)即为(wei)此电容的耐压值(zhi)。
(注:涤纶电(dian)容(rong)采用此法较(jiao)常见,其它电(dian)容(rong)应用此法少些)
例(li): 1A=10V 2A=100V 2B=125V
2C=160V 3D=2KV 3G=4KV
1E=25V 2F=315V 4W=45KV
④用颜(yan)色(se)来表示耐(nai)压
部(bu)分瓷(ci)介(jie)电容有颜(yan)色来表示(shi)其耐压(ya)(ya)值(zhi),即外表不同(tong)颜(yan)色来表示(shi)不同(tong)的耐压(ya)(ya)
⑤部分(fen)进(jin)口瓷介(陶瓷)电容,在(zai)容量下面(mian)画有一横线(xian)的则(ze)(ze)为(wei)耐(nai)压50V,不画横线(xian)的则(ze)(ze)为(wei)耐(nai)压500V。
⑥有(you)些电容的耐压单位有(you)WV表(biao)示V,如:50WV即50V、350WV即350V等。
⑦凡是没有用上述(shu)方法标明耐压值的(de),则该电容可认为(wei)是(shi)耐压25V(或以下)的低压电容。
①直接标明容量的(de)数值和单位,如:5PF、33PF、100PF、22nf、0.01uF、47uF、22F等。
(注:电(dian)(dian)解电(dian)(dian)容(rong)大多数采用(yong)此法)
②直(zhi)接标(biao)明容量的数值,而单位用u、n、p表示uF、nF、pF,如:47u即47Uf。
③用几X几代表几点几X,如:8P2即8.2Pf、6n8即6.8Nf、4u7即4.7uF等。
④凡是电容(rong)量的数值(zhi)用零点几或点几乖(guai)来表(biao)示而没有标明单位的(de)。其容量数值单位为零点几uF,如:0.01即0.01uF等(deng)。
⑤电容量的数(shu)值为(wei)整(zheng)数(shu)而(er)不标明(ming)单位的(de)。其单位为PF(注:三位数最后一(yi)位不为零的除外(wai))。如(ru):3即将(jiang)3PF、15即15PF、120即120PF等(deng)。
⑥数码表示法:用三位(wei)数(shu)(shu)字表示(shi)(注:最后一(yi)(yi)位(wei)为零的除外),第(di)一(yi)(yi)、二位(wei)数(shu)(shu)字表示(shi)有(you)效(xiao)数(shu)(shu),第(di)三位(wei)数(shu)(shu)字表示(shi)倍乘(cheng)(cheng)数(shu)(shu)(1为 101 、2为102 、3为 103 ……8为 108 ,但9却(que)为 100 )把有(you)效(xiao)数(shu)(shu)乘(cheng)(cheng)以倍乘(cheng)(cheng)数(shu)(shu),即为电(dian)容量,其单位(wei)为PF。
⑦色环(色条)表(biao)示法
与色环(huan)电阻表(biao)示(shi)法相同,但单位为(wei)PF
⑧有(you)厂(chang)家(jia)电容容量单位用大写(xie)英文MDF或(huo)MF代表(biao)uF。如:25MDF即(ji)25uF、100MF即(ji)100uF。
⑨有些(xie)电(dian)容(rong)在电(dian)容(rong)量(liang)的数值后面标有字母或正负百分之几的则(ze)为表(biao)示(shi)该电(dian)容(rong)的误差等级。
注:大多数厂家的(de)电(dian)容量误差等级用上述字(zi)母(mu)来表示(shi),但也有(you)个别(bie)厂家用其(qi)它(ta)字(zi)母(mu)或字(zi)符来表示(shi),误差等级在这(zhei)不一(yi)一(yi)举(ju)出。
①对于未剪脚的铝电解电容,则长脚端为正(zheng)而(er)短脚端为负。
②有极性电容在出厂前均要求标(biao)明(ming)正负极(可(ke)以正负极标(biao)明(ming),也可(ke)以只标(biao)明(ming)正极或(huo)负极端)可(ke)以从电容的(de)外壳(qiao)直(zhi)接看出。
③用(yong)(yong)万用(yong)(yong)表(biao)(biao)(biao)电(dian)(dian)阻(zu)(zu)(zu)档(dang)(dang)测试(shi)(shi)正负极(仅供参考) 用(yong)(yong)万用(yong)(yong)表(biao)(biao)(biao)电(dian)(dian)阻(zu)(zu)(zu)档(dang)(dang)的(de)(de)最高(gao)量(liang)程(cheng)档(dang)(dang)(RX1K或10K档(dang)(dang))测试(shi)(shi)有极性电(dian)(dian)解电(dian)(dian)容(rong)的(de)(de)正反(fan)向(xiang)漏电(dian)(dian)电(dian)(dian)阻(zu)(zu)(zu)(即绝(jue)(jue)缘(yuan)(yuan)(yuan)电(dian)(dian)阻(zu)(zu)(zu)大)时,而反(fan)向(xiang)漏电(dian)(dian)大(即绝(jue)(jue)缘(yuan)(yuan)(yuan)电(dian)(dian)阻(zu)(zu)(zu)小(xiao))的(de)(de)特点。当测试(shi)(shi)时表(biao)(biao)(biao)针先(xian)向(xiang)右边(bian)摆动(容(rong)量(liang)越(yue)大表(biao)(biao)(biao)针摆动也越(yue)大),然后慢慢向(xiang)左边(bian)退回来。若表(biao)(biao)(biao)针能(neng)(neng)退回到(dao)无(wu)穷大(刻度左边(bian)起始(shi)位置(zhi)(zhi)),则该电(dian)(dian)容(rong)量(liang)基(ji)本没(mei)有漏电(dian)(dian),若表(biao)(biao)(biao)针不能(neng)(neng)退回到(dao)无(wu)穷大位置(zhi)(zhi)而在某一(yi)(yi)刻度停下来,则此时的(de)(de)电(dian)(dian)阻(zu)(zu)(zu)阻(zu)(zu)(zu)值为(wei)漏电(dian)(dian)电(dian)(dian)阻(zu)(zu)(zu)(即绝(jue)(jue)缘(yuan)(yuan)(yuan)电(dian)(dian)阻(zu)(zu)(zu))反(fan)复测试(shi)(shi)多(duo)次(应调换表(biao)(biao)(biao)笔)测试(shi)(shi)出其(qi)正反(fan)向(xiang)漏电(dian)(dian)(绝(jue)(jue)缘(yuan)(yuan)(yuan)电(dian)(dian)阻(zu)(zu)(zu))。凡(fan)是(shi)漏电(dian)(dian)小(xiao)(即绝(jue)(jue)缘(yuan)(yuan)(yuan)电(dian)(dian)阻(zu)(zu)(zu)大)的(de)(de)一(yi)(yi)次则黑表(biao)(biao)(biao)笔接的(de)(de)电(dian)(dian)极为(wei)电(dian)(dian)解电(dian)(dian)容(rong)正极而红表(biao)(biao)(biao)笔接的(de)(de)为(wei)负极,反(fan)之则表(biao)(biao)(biao)笔极性刚好相(xiang)反(fan)。
注(zhu):黑表笔接电(dian)解电(dian)容(rong)正极而红(hong)表笔接负极测试(shi)正向漏电(dian)电(dian)阻(zu)。
红表笔(bi)接(jie)电(dian)(dian)解电(dian)(dian)容负极而黑表笔(bi)接(jie)正(zheng)极测(ce)试负向漏(lou)电(dian)(dian)电(dian)(dian)阻。
电容(rong)的(de)耐(nai)压(ya)可以从电容(rong)的(de)外表(biao)(biao)直(zhi)接看出(chu)(chu)而不用测(ce)试(shi),但若有耐(nai)压(ya)表(biao)(biao)的(de)情况下(xia)也(ye)可以用耐(nai)压(ya)表(biao)(biao)直(zhi)接测(ce)试(shi)出(chu)(chu)来。
①对于(yu)合格的电(dian)容(rong),其(qi)容(rong)量为电(dian)容(rong)外壳上标志值,一(yi)般可直接(jie)看出来而不用(yong)测试。
②若(ruo)有(you)电(dian)(dian)容(rong)表(部分数字万用表也可测(ce)试电(dian)(dian)容(rong)容(rong)量,但(dan)只能测(ce)试小电(dian)(dian)容(rong)容(rong)量而不能测(ce)大电(dian)(dian)容(rong)容(rong)量)。则可利(li)用电(dian)(dian)容(rong)表直接(jie)测(ce)试出电(dian)(dian)容(rong)的容(rong)量。
③部分指针万用(yong)表在串入(ru)一定电压(ya)值的交流电的情况下(xia)也可以(yi)测量(liang)出其电容容量(liang),但误差(cha)较大,不提倡(chang)采(cai)用(yong)。
④用(yong)(yong)(yong)普(pu)通机械式指针万(wan)用(yong)(yong)(yong)表(biao)也(ye)(ye)可(ke)粗略测(ce)试出电(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)的(de)(de)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)大(da)小,方法是用(yong)(yong)(yong)万(wan)用(yong)(yong)(yong)表(biao)的(de)(de)电(dian)(dian)(dian)阻(zu)档(dang)(容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)小要(yao)用(yong)(yong)(yong)高阻(zu)档(dang),而容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)大(da)要(yao)用(yong)(yong)(yong)低阻(zu)档(dang))。调换表(biao)笔(bi)测(ce)试多次,则电(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)越大(da)表(biao)针摆动(dong)幅度(du)也(ye)(ye)越大(da),而容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)越小表(biao)针摆动(dong)幅度(du)也(ye)(ye)越小,根(gen)据表(biao)针摆动(dong)幅度(du)的(de)(de)大(da)小与(yu)其标准(zhun)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)电(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)比较,即可(ke)估算(suan)该电(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)的(de)(de)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)大(da)小(注:一般情况(kuang)下使(shi)用(yong)(yong)(yong)电(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)的(de)(de)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)无须要(yao)求(qiu)特别精确,其电(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)只须在一定范围内(nei)即可(ke)正常使(shi)用(yong)(yong)(yong)。一般情况(kuang)下只用(yong)(yong)(yong)普(pu)通指针式万(wan)用(yong)(yong)(yong)表(biao)进行时电(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)(rong)量(liang)(liang)粗略测(ce)试即可(ke))。
注:当(dang)容量(liang)(liang)大(da)用(yong)高阻(zu)档测试时,表针(zhen)会(hui)打超刻度线而难(nan)以比较容量(liang)(liang)大(da)小(xiao),此时就降低量(liang)(liang)程测试以表针(zhen)不打超刻度为限,方能比较容量(liang)(liang)大(da)小(xiao)。
▲容(rong)(rong)量(liang)太(tai)小(小于0.01uF)则有最高阻档(dang)测试均准以看到表(biao)针摆(bai)动是正常的,对这些电容(rong)(rong)则难以用电阻档(dang)比较其容(rong)(rong)量(liang)大小,只采用电容(rong)(rong)表(biao)测试.
▲若(ruo)测(ce)试时表针(zhen)指到(dao)零欧处停下(xia)来不能(neng)退回来,则此时电(dian)容已短路(lu)损坏(huai),而不能(neng)测(ce)试其容量.
指(zhi)电容对交流(liu)电的等效电阻称(cheng)为(wei)容抗。
具有通高频(pin)阻(zu)低频(pin),通交(jiao)流阻(zu)直(zhi)流的(de)特性。
a)电容的用途
可用来滤波、耦(ou)合、退耦(ou)、旁路、调谐、谐振等(deng)用途。
b)电容的(de)好坏(huai)判断
用万用表(biao)(biao)(biao)判断电(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)档(dang)(容(rong)(rong)(rong)(rong)量(liang)小(xiao)一定要用高阻(zu)(zu)(zu)档(dang)而(er)(er)(er)容(rong)(rong)(rong)(rong)量(liang)大(da)(da)可(ke)用低(di)阻(zu)(zu)(zu)档(dang))测(ce)试(shi)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)时(应(ying)(ying)(ying)调换(huan)表(biao)(biao)(biao)笔测(ce)试(shi)多次(ci)或把电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)短(duan)路放电(dian)(dian)(dian)(dian)(dian)后再测(ce)试(shi))容(rong)(rong)(rong)(rong)量(liang)大(da)(da)表(biao)(biao)(biao)针(zhen)(zhen)摆(bai)(bai)动(dong)(dong)幅(fu)(fu)度(du)(du)也越(yue)大(da)(da),且表(biao)(biao)(biao)针(zhen)(zhen)摆(bai)(bai)动(dong)(dong)后应(ying)(ying)(ying)慢慢退(tui)回(hui)(hui)来为(wei)正(zheng)常(chang)(即只(zhi)有这样该(gai)(gai)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)才是好(hao)的(de)(de)(de))。若与同容(rong)(rong)(rong)(rong)量(liang)好(hao)的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)比较(jiao)在(zai)测(ce)试(shi)表(biao)(biao)(biao)针(zhen)(zhen)摆(bai)(bai)动(dong)(dong)幅(fu)(fu)度(du)(du)过(guo)小(xiao)功根(gen)本不摆(bai)(bai)动(dong)(dong)则(ze)该(gai)(gai)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)容(rong)(rong)(rong)(rong)量(liang)已变小(xiao)或失效损坏,同时表(biao)(biao)(biao)针(zhen)(zhen)摆(bai)(bai)动(dong)(dong)应(ying)(ying)(ying)慢慢退(tui)回(hui)(hui)来(容(rong)(rong)(rong)(rong)量(liang)小(xiao)退(tui)回(hui)(hui)速度(du)(du)快而(er)(er)(er)容(rong)(rong)(rong)(rong)量(liang)大(da)(da)退(tui)回(hui)(hui)速度(du)(du)慢)。若退(tui)回(hui)(hui)到某一位置表(biao)(biao)(biao)针(zhen)(zhen)停(ting)下(xia)来则(ze)此(ci)时的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)为(wei)该(gai)(gai)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)的(de)(de)(de)漏(lou)(lou)电(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)。此(ci)漏(lou)(lou)电(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)越(yue)大(da)(da)越(yue)好(hao)(最好(hao)为(wei)无穷大(da)(da)),此(ci)漏(lou)(lou)电(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)过(guo)小(xiao)则(ze)该(gai)(gai)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)漏(lou)(lou)电(dian)(dian)(dian)(dian)(dian)过(guo)大(da)(da)而(er)(er)(er)性能(neng)不良,此(ci)漏(lou)(lou)电(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)基(ji)本为(wei)零(ling)(即表(biao)(biao)(biao)针(zhen)(zhen)在(zai)刻度(du)(du)零(ling)欧(ou)停(ting)下(xia)来),则(ze)该(gai)(gai)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)已短(duan)路(击(ji)穿)损坏。对(dui)于容(rong)(rong)(rong)(rong)量(liang)较(jiao)小(xiao)的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)用电(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)档(dang)的(de)(de)(de)最高档(dang)均难以看到表(biao)(biao)(biao)针(zhen)(zhen)摆(bai)(bai)动(dong)(dong)是正(zheng)常(chang)的(de)(de)(de)。但若该(gai)(gai)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)有漏(lou)(lou)电(dian)(dian)(dian)(dian)(dian)或击(ji)穿短(duan)路现象则(ze)可(ke)能(neng)测(ce)试(shi)出来(注:对(dui)于此(ci)类电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)有漏(lou)(lou)电(dian)(dian)(dian)(dian)(dian)或击(ji)穿睦均可(ke)认为(wei)该(gai)(gai)电(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)已性能(neng)不良或损坏而(er)(er)(er)不要使用)
①对于(yu)容(rong)(rong)大于(yu)1uF的无(wu)极性(xing)电(dian)(dian)容(rong)(rong),用万用表电(dian)(dian)阻档(dang)(dang)的RX1K档(dang)(dang)或(huo)10K档(dang)(dang)测试时应能明显看出(chu)表针(zhen)向右摆动后较快(kuai)退回到无(wu)穷大位置为(wei)正(zheng)常。若不能退回到无(wu)穷大位置则该电(dian)(dian)容(rong)(rong)有漏(lou)电(dian)(dian)现象而最好(hao)不要(yao)使用它,若漏(lou)电(dian)(dian)电(dian)(dian)阻基本为(wei)零则该电(dian)(dian)容(rong)(rong)已经(jing)击穿短(duan)路损坏(huai)。
②对于(yu)容(rong)量大于(yu)0.01uF(10uF)而小(xiao)(xiao)于(yu)1uF的(de)(de)无极(ji)性电(dian)(dian)容(rong),用电(dian)(dian)阻档的(de)(de)最高量程(最好(hao)用RX10K档,用X1K档有些(xie)电(dian)(dian)容(rong)难(nan)以观察)档,测试时应能看到(dao)表(biao)针较微(wei)摆动(dong)(dong)(即表(biao)针摆动(dong)(dong)很小(xiao)(xiao))后很快退回(hui)到(dao)无穷(qiong)大位置(zhi)为正(zheng)常(chang),并且不(bu)能有漏(lou)电(dian)(dian)或短路现象,否则该电(dian)(dian)容(rong)不(bu)良(liang)或损坏。
③对于容(rong)(rong)量(liang)小于0.01uF(10nF即10000pF)的(de)(de)无极(ji)性电(dian)容(rong)(rong),用(yong)万用(yong)表(biao)电(dian)阻档的(de)(de)最高量(liang)程(如(ru):测试时(shi)均难以看到表(biao)针(zhen)摆动(dong)(因容(rong)(rong)量(liang)太小,表(biao)笔(bi)刚接触(chu)电(dian)容(rong)(rong)时(shi)已对该电(dian)容(rong)(rong)充电(dian)完(wan)毕而表(biao)针(zhen)还来不(bu)及摆动(dong))是正常(chang)的(de)(de)。若(ruo)怀疑这些电(dian)容(rong)(rong)容(rong)(rong)量(liang)变小或失(shi)效损坏则只能(neng)用(yong)电(dian)容(rong)(rong)表(biao)测试或在实际应用(yong)中代(dai)(dai)换法(替代(dai)(dai)法)即用(yong)一个(ge)好(hao)的(de)(de)代(dai)(dai)替怀疑已损坏的(de)(de))进行判(pan)断,对这些电(dian)容(rong)(rong)绝对在测试时(shi)不(bu)能(neng)有漏电(dian)功短路(lu)现象,否则均可认(ren)为该电(dian)容(rong)(rong)已损坏而不(bu)能(neng)继续使用(yong)。
④对于(yu)(yu)有极(ji)性(xing)(xing)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)解电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong),由于(yu)(yu)容(rong)(rong)量(liang)较大(da),故测(ce)试时(shi)可(ke)(ke)根据容(rong)(rong)量(liang)大(da)小(xiao)(xiao)(xiao)(xiao)选择(ze)适合的(de)档位(wei)(wei)(wei)量(liang)程来(lai)进行测(ce)试(即(ji)(ji)容(rong)(rong)量(liang)小(xiao)(xiao)(xiao)(xiao)用(yong)高档而(er)容(rong)(rong)量(liang)大(da)用(yong)低档,如:10uF以(yi)下可(ke)(ke)用(yong)X10K或X1K档,100uF左右可(ke)(ke)用(yong)X1K或X100 档,1000uF以(yi)下可(ke)(ke)用(yong)X100或 ,1000uF以(yi)上(shang)可(ke)(ke)用(yong)RX10或 ,以(yi)上(shang)档位(wei)(wei)(wei)选择(ze)供参(can)考(kao))测(ce)试时(shi)应(ying)该(gai)容(rong)(rong)量(liang)越(yue)(yue)(yue)大(da)表(biao)(biao)(biao)针摆(bai)动(dong)越(yue)(yue)(yue)大(da)。(同档位(wei)(wei)(wei)置量(liang)程比较)并且(qie)表(biao)(biao)(biao)针摆(bai)动(dong)后应(ying)该(gai)会慢(man)慢(man)退回(hui)来(lai)正(zheng)常。表(biao)(biao)(biao)针退回(hui)到某一刻(ke)度位(wei)(wei)(wei)置停下来(lai)而(er)不能退回(hui)到无(wu)穷(qiong)大(da)(即(ji)(ji)表(biao)(biao)(biao)针刻(ke)度起始位(wei)(wei)(wei)置),则表(biao)(biao)(biao)明该(gai)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)有漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)现象,漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)越(yue)(yue)(yue)小(xiao)(xiao)(xiao)(xiao)(即(ji)(ji)漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻越(yue)(yue)(yue)大(da))越(yue)(yue)(yue)好,若(ruo)漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)过大(da)(即(ji)(ji)漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻越(yue)(yue)(yue)小(xiao)(xiao)(xiao)(xiao))则该(gai)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)性(xing)(xing)能不良,若(ruo)漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻基本(ben)为零,则该(gai)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)已(yi)击穿(chuan)损(sun)坏。同时(shi)由于(yu)(yu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)解电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)具有正(zheng)向漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)小(xiao)(xiao)(xiao)(xiao)(即(ji)(ji)漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻大(da))而(er)反向漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)大(da)(即(ji)(ji)漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻小(xiao)(xiao)(xiao)(xiao))的(de)特点。故测(ce)试的(de)一般正(zheng)向漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)较小(xiao)(xiao)(xiao)(xiao)即(ji)(ji)可(ke)(ke),而(er)反向漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)大(da)小(xiao)(xiao)(xiao)(xiao)可(ke)(ke)不考(kao)虑,还有对于(yu)(yu)有极(ji)性(xing)(xing)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)解电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong),若(ruo)存放时(shi)间(jian)过长其漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)也会变大(da),只要使用(yong)一段时(shi)间(jian)甚至测(ce)试多次其漏(lou)(lou)(lou)(lou)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)也会变小(xiao)(xiao)(xiao)(xiao)。
简称(cheng)电感,俗称(cheng)线圈(quan),是由线圈(quan)绕(rao)制(zhi)而成的具有电感作用的元件(jian)。
①空芯电(dian)感:指线圈绕(rao)在空心(xin)支架(jia)上或直接绕(rao)制而(er)成的电(dian)感。
②磁芯电感:指线(xian)圈(quan)绕在磁芯上(即(ji)线(xian)圈(quan)里(li)面有磁芯)形成的(de)。
③铜芯(xin)电感(gan):指(zhi)线圈绕在铜芯(xin)上的(de)电感(gan)。
④铁(tie)(tie)芯电感:指线圈(quan)绕在(zai)铁(tie)(tie)芯上的电感。
⑤带抽(chou)(chou)头(tou)电感:指线(xian)圈上(shang)抽(chou)(chou)出(chu)一个或多(duo)个抽(chou)(chou)头(tou)的电感。
指电(dian)感(gan)能(neng)力大小(xiao)的量,称(cheng)为电(dian)感(gan)量。电(dian)感(gan)量的基本单位(wei)为亨(heng)利,简称(cheng)亨(heng)(H),常用(yong)单位(wei)还(hai)有(you)毫(hao)亨(heng)(mH),微(wei)亨(heng)(μH)等。
1H=103 mH=106μH
指电感对(dui)交流电的(de)阻碍作用(即(ji)等效电阻)。XL=2лfL
具(ju)有(you)通直流阻交流,通低频阻高频的(de)特(te)性。
当通过(guo)电感(gan)线圈(quan)(quan)的(de)电流发生变(bian)(bian)化时(shi),线圈(quan)(quan)将产生一(yi)个自(zi)感(gan)电动势来阻(zu)碍电流的(de)变(bian)(bian)化,这种作用(yong)叫(jiao)电感(gan)的(de)自(zi)感(gan)作用(yong)。
两个(ge)相互靠近(jin)的(de)线圈,当一个(ge)有变(bian)化的(de)电流通过时另一个(ge)也会感应出(chu)感生电动势,这种作(zuo)用(yong)叫(jiao)电感的(de)互感作(zuo)用(yong)。变(bian)压器就是根据互感作(zuo)用(yong)原理制成的(de)。
可用于滤波,阻波,限流,变换(huan),调谐,消(xiao)振等作(zuo)用。
①直(zhi)接标明电感量的数值(zhi)和单(dan)位。如:10mH ,150μH。
②用几(ji)(ji)X几(ji)(ji)代表(biao)几(ji)(ji)点几(ji)(ji)X。如:1H2即(ji)1.2H,3m3即(ji)3.3mH,8μ2即(ji)8.2μH。
③用色环或色点表(biao)示法:用四色(se)环(色(se)点(dian))来表(biao)示(shi),第(di)一二色(se)环(色(se)点(dian))表(biao)示(shi)有效数(shu),第(di)三色(se)环(色(se)点(dian))表(biao)示(shi)倍(bei)乘数(shu),第(di)四色(se)环表(biao)示(shi)误(wu)差。(与四色(se)环电阻表(biao)示(shi)方法相(xiang)同)
灰红棕(zong)金 即是82X101±5%
④用圈数(匝(za)数)表示
有些电(dian)(dian)感(gan)线圈(quan)(quan)不标明(ming)其电(dian)(dian)感(gan)量而直接标明(ming)该电(dian)(dian)感(gan)线圈(quan)(quan)应该绕制的圈(quan)(quan)数(匝(za)数),如:3T即(ji)3圈(quan)(quan)(匝(za)),19T即(ji)19匝(za)等。
⑤有很多电感线圈(quan)是由厂家制(zhi)定,其上面既无电感量也没(mei)有标明绕(rao)制(zhi)的圈(quan)数,在实(shi)际(ji)应用中,只能用相(xiang)同(tong)的线圈(quan)更换或(huo)按原来规格重绕(rao)。
用(yong)万用(yong)表电(dian)(dian)(dian)阻(zu)档可粗(cu)略测试电(dian)(dian)(dian)感线(xian)(xian)圈(quan)的(de)好坏(huai),方法是测试线(xian)(xian)圈(quan)两端的(de)直流(liu)电(dian)(dian)(dian)阻(zu)与正(zheng)常值比较或(huo)相同的(de)线(xian)(xian)圈(quan)比较,若(ruo)电(dian)(dian)(dian)阻(zu)值基(ji)本相同(误差≤±10%)则(ze)(ze)可以认为(wei)该线(xian)(xian)圈(quan)是好的(de),若(ruo)电(dian)(dian)(dian)阻(zu)值相差过(guo)大则(ze)(ze)该线(xian)(xian)圈(quan)不良(liang),若(ruo)电(dian)(dian)(dian)阻(zu)值变(bian)为(wei)无穷大则(ze)(ze)该线(xian)(xian)圈(quan)已开(kai)路(lu)损坏(huai),若(ruo)电(dian)(dian)(dian)阻(zu)值变(bian)为(wei)零则(ze)(ze)该线(xian)(xian)圈(quan)已短(duan)路(lu)损坏(huai)。
①电感(gan)线圈若发生短路或者局部(bu)短路的故障时应把线圈拆开按(an)原(yuan)来规(gui)格重(zhong)绕即可修(xiu)复。
②电感(gan)线圈(quan)若发生内部接触(chu)不良或(huo)开路故障时可(ke)小心拆开线圈(quan)检(jian)查,接触(chu)不良处(chu)(多为线圈(quan)接头处(chu))或(huo)断路处(chu)重(zhong)(zhong)新焊接牢(lao)固即可(ke)修(xiu)复,也(ye)可(ke)按原来(lai)规格用新线重(zhong)(zhong)绕来(lai)修(xiu)复。
③在大多数(shu)情况(kuang)(kuang)下若(ruo)电感线圈有(you)(you)故(gu)障时若(ruo)有(you)(you)新备件的情况(kuang)(kuang)下建议更(geng)换解(jie)决,若(ruo)无新备件的情况(kuang)(kuang)下才对其(qi)进(jin)行修复。
变压(ya)器(qi)是一种能(neng)变换交流电压(ya)、电流及阻抗的多(duo)线圈器(qi)件。
1.变压(ya)器(qi)变换交流电压(ya)电流及阻抗的关系:
N1,N2分别为初(chu)次级(ji)的(de)圈(quan)数;U1,U2分别为初(chu)次级(ji)的(de)电压;I1,I2分别为初(chu)次的(de)电流;Z1,Z2分别为初(chu)次级(ji)的(de)阻抗。初(chu)级(ji)线(xian)(xian)圈(quan)(N1)又叫(jiao)原线(xian)(xian)圈(quan);次级(ji)线(xian)(xian)圈(quan)(N2)又叫(jiao)副线(xian)(xian)圈(quan)。
变压(ya)器初(chu)次级(ji)圈数(shu)比与(yu)初(chu)次级(ji)电压(ya)成(cheng)正比,与(yu)初(chu)次级(ji)电流成(cheng)反(fan)比,与(yu)初(chu)次级(ji)阻抗的(de)开方成(cheng)正比。用公式表示为:
①高(gao)频变压器(qi):指用于变(bian)换高频(pin)电(dian)信号的变(bian)压(ya)器(qi)。如天线(xian)线(xian)圈(quan),振荡变(bian)压(ya)器(qi)等。
②中频变压器:(俗称中(zhong)周):指超外差无线电接收机中(zhong)用于变换中(zhong)颇电信号的变压器。
③低频(pin)变(bian)压器:指用于(yu)变(bian)(bian)换低(di)频电信(xin)号的(de)变(bian)(bian)压(ya)(ya)器,如音频变(bian)(bian)压(ya)(ya)器。
④电源变压器:指用于变换(huan)交流市(shi)电(dian)的变压器。
⑤自耦(ou)变压器(qi):指初次级线圈可共用的变(bian)压器。
用(yong)万用(yong)表电(dian)阻(zu)档可粗略判(pan)断(duan)变压器(qi)(qi)的(de)(de)(de)好坏,方法是测(ce)量变压器(qi)(qi)各(ge)线圈(quan)(quan)(quan)(quan)的(de)(de)(de)直流电(dian)阻(zu)与正常值或好的(de)(de)(de)变压器(qi)(qi)比(bi)较,若所有(you)线圈(quan)(quan)(quan)(quan)的(de)(de)(de)阻(zu)值正常,则(ze)(ze)可以认(ren)为该变压器(qi)(qi)是好的(de)(de)(de);若有(you)一个(ge)或多个(ge)线圈(quan)(quan)(quan)(quan)不(bu)良或损(sun)坏。同时测(ce)试不(bu)同线圈(quan)(quan)(quan)(quan)之间或各(ge)线圈(quan)(quan)(quan)(quan)与外壳(qiao)(铁芯)之间的(de)(de)(de)绝缘电(dian)阻(zu)应为无穷大为正常,否(fou)则(ze)(ze)该变压器(qi)(qi)也是不(bu)良或损(sun)坏。
①变压器(qi)初级线圈串联(lian)有(you)温(wen)度保(bao)(bao)险(xian)丝(si)(si)的变压器(qi),若发生初级开路时,则多(duo)为此(ci)温(wen)度保(bao)(bao)险(xian)丝(si)(si)熔断引起(qi),可更(geng)换一个温(wen)度保(bao)(bao)险(xian)丝(si)(si)解决,若无(wu)此(ci)保(bao)(bao)险(xian)丝(si)(si)更(geng)换的情况下也可以(yi)短(duan)路此(ci)保(bao)(bao)险(xian)来解决。
②对(dui)于一般变压器,若线圈损坏时(shi),则可按原线圈的参(can)数重绕(rao)即可修复。
③在大(da)多(duo)数情况下变(bian)压器(qi)损坏难修复或修复工(gong)程太大(da)时则建(jian)议换解决。
①铁(tie)芯截面(mian)积(S):S=舌(she)宽×叠厚
②铁芯截面积(ji)(S)与变压器功(gong)率(P)的(de)关系:S=1.25
③每伏(fu)圈数(shu)(N):指(zhi)每伏电压应(ying)绕制的线圈圈数(匝数)
f为(wei)交流电频率,S为(wei)铁芯截面积,Bmax为(wei)磁感应(ying)强(qiang)度(du)
④初级(ji)圈数(N1)与次级(ji)圈数(N2)
N1=U1N(U1为(wei)(wei)初级(ji)电(dian)(dian)压(ya));N2=U2N(U2为(wei)(wei)次级(ji)电(dian)(dian)压(ya))
⑤线(xian)径(jing)(d):指绕制线(xian)圈的(de)导线(xian)直径(jing)(mm)。
I为导线的电流(I=P/U)
初级线径d1=;次(ci)级线径
简称二(er)极管,是一种(zhong)双(shuang)层(ceng)结(jie)构的半导体器件,由一个(ge)PN结(jie)组成(cheng),具有单(dan)向(xiang)导电的特性。
1. PN结
① P型半导(dao)体:指空穴多数为载流(liu)子(zi)的杂质(zhi)半导体。
② N型半导体(ti):指电子(zi)为多数(shu)载流子(zi)的杂质(zhi)半导(dao)体。
③ PN结:把P型半(ban)导(dao)体(ti)(ti)与N型半(ban)导(dao)体(ti)(ti)复合,在其交界面处形成(cheng)的空间(jian),电荷区(qu)(即阻挡(dang)层)叫PN结。
④ PN结的特性:具有单向导(dao)电的(de)特性。
①正向电流:指正向导通时(shi)允许通过的电大电流。
②反向击穿(chuan)电压:指PN结反向(xiang)击穿时的电(dian)高电(dian)压(ya),即是(shi)二极管(guan)的耐压(ya)。
③正向导(dao)通电(dian)压:指正(zheng)向导通时所需的电压。锗材料(liao)(liao)(PN结(jie)):0.2V(0.2—0.3V);硅材料(liao)(liao)(PN结(jie)):0.6V(0.5—0.7V);化合物材料(liao)(liao)2V左右(you)(1—3V)。
④ 结电容:指PN结形成的电容称为结电容。
可(ke)用(yong)于整流、稳压、开关(guan)、阻尼、调(diao)谐(xie)等用(yong)途。
①对于一般二极管,有标志(如色圈(quan))的一端(duan)为负(fu)极而(er)另一端(duan)为正极。
②对于发光(guang)二极管,若未剪脚(jiao)(jiao)(jiao)的情(qing)况下则长脚(jiao)(jiao)(jiao)为正极,短脚(jiao)(jiao)(jiao)为负极。
③对于(yu)二(er)极(ji)管,大多数可以从(cong)其(qi)内部(bu)构造直接看出其(qi)正负(fu)极(ji)。
④用(yong)万(wan)用(yong)表(biao)(biao)电(dian)(dian)阻档(dang)判断:用(yong)万(wan)用(yong)表(biao)(biao)电(dian)(dian)阻档(dang)测(ce)试二极(ji)(ji)管的(de)正(zheng)反(fan)向电(dian)(dian)阻时,根据(ju)二极(ji)(ji)管的(de)PN结具有正(zheng)向电(dian)(dian)阻小(xiao)(xiao)反(fan)向电(dian)(dian)阻大的(de)特点来判断。测(ce)试时电(dian)(dian)阻小(xiao)(xiao)的(de)一次(ci)黑表(biao)(biao)笔接的(de)为(wei)正(zheng)极(ji)(ji),而红(hong)表(biao)(biao)笔接的(de)是负(fu)极(ji)(ji)。
用万(wan)用表电阻(zu)档(dang)测试二(er)极管(guan)的正反向(xiang)(xiang)电阻(zu)时,二(er)极管(guan)(PN结)正向(xiang)(xiang)电阻(zu)越(yue)小越(yue)好,反向(xiang)(xiang)电阻(zu)越(yue)大越(yue)好。若二(er)极管(guan)的正反向(xiang)(xiang)电阻(zu)都很(hen)小或(huo)(huo)很(hen)大则(ze)此管(guan)已击穿短路或(huo)(huo)开路损坏。
三极管(guan)是(shi)一(yi)种对信号具(ju)有(you)放大和开关作用(yong)的三层结构(gou)的半导体(ti)器(qi)件,由两个PN结组成。
三极(ji)管分为PNP型(xing)(xing)和NPN型(xing)(xing)两种(zhong)类型(xing)(xing)的结构(gou)。
E或(huo)(huo)e代(dai)表(biao)发射极,B或(huo)(huo)b代(dai)表(biao)基(ji)极,C或(huo)(huo)c代(dai)表(biao)集电极,BC结(jie)(bc结(jie)):集电结(jie)
BE结(be 结):发射(she)结
①PCM:指集电极最(zui)大(da)耗散(san)功率(lv),即是三极管的(de)最(zui)大(da)功率(lv)。PCM<1W为小功率(lv)管;PCM>1W为大(da)功率(lv)管;PCM=1W左(zuo)右的(de)为中功率(lv)管。
②ICM:指集电(dian)极最(zui)大(da)电(dian)流,即是(shi)三极管的最(zui)大(da)电(dian)流。
③Bvceo:指基(ji)极(ji)开路(lu)时(shi)集(ji)电(dian)极(ji)与发射(she)极(ji)的(de)最大反向(xiang)击(ji)穿电(dian)压,即是三极(ji)管的(de)耐压。
④Iceo :指基极开路时集电(dian)(dian)极与发(fa)射极的最大反(fan)向漏电(dian)(dian)电(dian)(dian)流,即是(shi)三极管的穿(chuan)透电(dian)(dian)流。
⑤fT:指特征频(pin)率,即是指在其发射极放(fang)大电(dian)路中放(fang)大倍数下降到(dao)1时的频(pin)率。
fT≤3MHz为(wei)低(di)频管(guan);fT>3MHz为(wei)高频管(guan);fT>几百MHz称为(wei)超高频管(guan)
⑥hFE:指三极管的直流放大(da)系(xi)数(直流放大(da)倍数)
hFE=(Ic为集电(dian)极电(dian)流(liu),IB为基极电(dian)流(liu))
⑦β值:指三(san)极管(guan)的交流放大倍数
(ΔIC为集电极(ji)电流(liu)变化量(liang),ΔIB为基极(ji)电流(liu)变化量(liang))
用万用表(biao)(biao)电(dian)(dian)(dian)阻(zu)档测试三极(ji)管(guan)各脚之(zhi)间(jian)的(de)正反向电(dian)(dian)(dian)阻(zu)时,凡是(shi)有一(yi)(yi)次红(hong)表(biao)(biao)笔(bi)接(jie)固定一(yi)(yi)个电(dian)(dian)(dian)极(ji)是(shi),黑表(biao)(biao)笔(bi)分(fen)别接(jie)其余两个电(dian)(dian)(dian)极(ji)电(dian)(dian)(dian)阻(zu)都(dou)比较小,则(ze)此管(guan)为PNP管(guan)(简称P管(guan)),且红(hong)表(biao)(biao)笔(bi)接(jie)的(de)电(dian)(dian)(dian)极(ji)为基极(ji);若凡是(shi)有一(yi)(yi)次黑表(biao)(biao)笔(bi)接(jie)固定一(yi)(yi)个电(dian)(dian)(dian)极(ji),红(hong)表(biao)(biao)笔(bi)分(fen)别接(jie)其余两个电(dian)(dian)(dian)极(ji)电(dian)(dian)(dian)阻(zu)都(dou)比较小,则(ze)此管(guan)为NPN管(guan)(简称N管(guan))且黑表(biao)(biao)笔(bi)接(jie)的(de)为基极(ji)。
根据上述方法判断(duan)出(chu)(chu)PNP与(yu)NPN管(guan)(guan)且找出(chu)(chu)了基极(ji)后,余(yu)下的(de)(de)(de)(de)两(liang)个电(dian)(dian)极(ji)可(ke)(ke)用(yong)下述方法判断(duan),方法是:万(wan)用(yong)表(biao)(biao)(biao)置电(dian)(dian)阻(zu)档的(de)(de)(de)(de)RX1K档,红黑表(biao)(biao)(biao)笔(bi)(bi)(bi)分别(bie)接余(yu)下的(de)(de)(de)(de)两(liang)个电(dian)(dian)极(ji),若为(wei)PNP型(xing)(xing)管(guan)(guan)则在红表(biao)(biao)(biao)笔(bi)(bi)(bi)接的(de)(de)(de)(de)电(dian)(dian)极(ji)与(yu)基极(ji)之间(jian)并接一个100K左右的(de)(de)(de)(de)电(dian)(dian)阻(zu)(此(ci)电(dian)(dian)阻(zu)可(ke)(ke)用(yong)手(shou)指(zhi)代(dai)替(ti))此(ci)时(shi)表(biao)(biao)(biao)针(zhen)若有(you)明(ming)显(xian)变化,则红表(biao)(biao)(biao)笔(bi)(bi)(bi)接的(de)(de)(de)(de)电(dian)(dian)极(ji)为(wei)集电(dian)(dian)极(ji),而黑表(biao)(biao)(biao)笔(bi)(bi)(bi)接的(de)(de)(de)(de)电(dian)(dian)极(ji)为(wei)发射(she)极(ji);若此(ci)管(guan)(guan)为(wei)NPN型(xing)(xing)管(guan)(guan)测试时(shi)表(biao)(biao)(biao)笔(bi)(bi)(bi)极(ji)性刚好相(xiang)反(fan),其测试方法与(yu)PNP型(xing)(xing)管(guan)(guan)完全相(xiang)同。
基极(ji)(ji)电(dian)流(liu)有微小的变化,集电(dian)极(ji)(ji)电(dian)流(liu)就有较大的变化,即用小电(dian)流(liu)去控制大电(dian)流(liu)从而实现(xian)电(dian)流(liu)的放(fang)大,这就是三(san)极(ji)(ji)管的放(fang)大作用原理。
用(yong)万能(neng)表(biao)电(dian)(dian)阻(zu)(zu)(zu)档(dang)测(ce)(ce)试(shi)三极管(guan)(guan)两(liang)个PN结(jie)(jie)(发(fa)射结(jie)(jie)和集电(dian)(dian)结(jie)(jie),即(ji)be结(jie)(jie)和bc结(jie)(jie))的(de)(de)(de)正(zheng)(zheng)向电(dian)(dian)阻(zu)(zu)(zu)越(yue)(yue)小(xiao)(用(yong)Rx1K档(dang)测(ce)(ce)试(shi)量(liang)时(shi)为(wei)几K欧左(zuo)右(you))越(yue)(yue)好,而反(fan)向电(dian)(dian)阻(zu)(zu)(zu)越(yue)(yue)大(da)(da)(da)(da)(da)(用(yong)Rx1K档(dang)测(ce)(ce)试(shi)时(shi)为(wei)几十(shi)(shi)K欧以(yi)上(shang),且大(da)(da)(da)(da)(da)多数管(guan)(guan)子为(wei)无(wu)(wu)穷大(da)(da)(da)(da)(da))越(yue)(yue)好,若(ruo)(ruo)两(liang)个或(huo)(huo)其中一个PN结(jie)(jie)的(de)(de)(de)正(zheng)(zheng)向电(dian)(dian)阻(zu)(zu)(zu)过(guo)大(da)(da)(da)(da)(da)(如(ru)(ru)Rx1K档(dang)测(ce)(ce)试(shi)有(you)几十(shi)(shi)欧以(yi)上(shang))或(huo)(huo)反(fan)向电(dian)(dian)阻(zu)(zu)(zu)过(guo)小(xiao)(如(ru)(ru)Rx1K档(dang)测(ce)(ce)试(shi)小(xiao)于几十(shi)(shi)K欧)则(ze)(ze)此管(guan)(guan)性能(neng)不(bu)良,若(ruo)(ruo)两(liang)个或(huo)(huo)其中一个PN结(jie)(jie)的(de)(de)(de)正(zheng)(zheng)反(fan)向电(dian)(dian)阻(zu)(zu)(zu)都很(hen)小(xiao)(如(ru)(ru)基(ji)本为(wei)零)或(huo)(huo)都很(hen)大(da)(da)(da)(da)(da)(如(ru)(ru)基(ji)本为(wei)无(wu)(wu)穷大(da)(da)(da)(da)(da))则(ze)(ze)此管(guan)(guan)由于两(liang)个或(huo)(huo)一个PN结(jie)(jie)击穿或(huo)(huo)开路损(sun)坏。同时(shi)集电(dian)(dian)极与发(fa)射析之间(jian)的(de)(de)(de)正(zheng)(zheng)反(fan)电(dian)(dian)阻(zu)(zu)(zu)越(yue)(yue)大(da)(da)(da)(da)(da)(最好为(wei)无(wu)(wu)穷大(da)(da)(da)(da)(da),但有(you)些(xie)管(guan)(guan)子在几十(shi)(shi)K欧以(yi)上(shang))越(yue)(yue)陷越(yue)(yue)好。若(ruo)(ruo)此管(guan)(guan)电(dian)(dian)阻(zu)(zu)(zu)过(guo)小(xiao)则(ze)(ze)该(gai)管(guan)(guan)穿透电(dian)(dian)流过(guo)大(da)(da)(da)(da)(da)而性能(neng)不(bu)良,若(ruo)(ruo)此电(dian)(dian)阻(zu)(zu)(zu)基(ji)本为(wei)零则(ze)(ze)该(gai)管(guan)(guan)集发(fa)之间(jian)已击穿损(sun)坏,还有(you)用(yong)HFE档(dang)测(ce)(ce)量(liang)或(huo)(huo)用(yong)电(dian)(dian)阻(zu)(zu)(zu)档(dang)估测(ce)(ce)三极管(guan)(guan)的(de)(de)(de)放(fang)(fang)大(da)(da)(da)(da)(da)能(neng)力(HFE值),管(guan)(guan)子类型(xing)用(yong)途不(bu)同其放(fang)(fang)大(da)(da)(da)(da)(da)能(neng)力也(ye)不(bu)同,但应有(you)放(fang)(fang)大(da)(da)(da)(da)(da)能(neng)力(HFE值应有(you)几倍(bei)以(yi)上(shang),而没有(you)放(fang)(fang)大(da)(da)(da)(da)(da)能(neng)力的(de)(de)(de)管(guan)(guan)子则(ze)(ze)不(bu)能(neng)用(yong)。)
①.三(san)(san)极(ji)(ji)管性能不(bu)良或(huo)损坏(huai)时,则(ze)不(bu)能对三(san)(san)极(ji)(ji)管进行(xing)修整而只能换新(xin)或(huo)好的三(san)(san)极(ji)(ji)管解决。
②.三极管(guan)损(sun)坏时,应尽可能(neng)(neng)选(xuan)择用同型(xing)号的(de)管(guan)子更(geng)换。若没有同型(xing)号管(guan)子时,则(ze)应选(xuan)用性(xing)能(neng)(neng)参数相同或相近的(de)管(guan)子。
③选用代(dai)(dai)用管(guan)子(zi)时,其参数(shu)Icm,Pcm,Bvceo等参数(shu)应等于(yu)或大于(yu)原型号管(guan)子(zi)方可代(dai)(dai)替。
④低(di)(di)频(pin)管(guan)只能在低(di)(di)频(pin)电路中应用(yong),而高频(pin)管(guan)不但可(ke)以(yi)在高频(pin)电路中应用(yong)而且(qie)可(ke)以(yi)在低(di)(di)频(pin)电路中应用(yong)。故在实际应用(yong)中高频(pin)管(guan)可(ke)代替低(di)(di)频(pin)管(guan),反之则不能。
1.中国(guo)
由数(shu)字---字母---字母---数(shu)字---(字母)组成
① 第一项数(shu)字表示电极数(shu)目,如:2——二极管,3—-三极管
② 第二项字母(mu)表示材料和极性(xing),如:A——锗(zhe)材料PNP型(xing) B——锗(zhe)材料NPN型(xing)
C——硅(gui)材(cai)料PNP型 D——硅(gui)材(cai)料NPN型 E——化(hua)合(he)物材(cai)料
③ 第三(san)项字母表示器(qi)件的类型(xing),如:
G——高频小(xiao)功率(lv)管 A——高频大功率(lv)管
X——低频小功率(lv)管(guan) D——低频大功率(lv)管(guan)
K——开(kai)关管(guan) W——稳(wen)压(ya)管(guan) P——普通管(guan) E——整流(liu)管(guan) N——阻尼管(guan) B——变容管(guan)
④ 第四(si)项数字,表示登记序号(hao)
⑤ 第(di)五项字母,用字母A,B,C,D等表(biao)示原(yuan)型(xing)的改进型(xing)
例:2AP9——锗普(pu)通(tong)二极(ji)管 2CW56——硅(gui)稳压二极(ji)管 3DG6B——硅(gui)NPN型(xing)(xing)高频(pin)(pin)小(xiao)(xiao)功率(lv)(lv)管为3DG6的改进型(xing)(xing) 3AX31——锗PNP型(xing)(xing)低(di)(di)频(pin)(pin)小(xiao)(xiao)功率(lv)(lv)三极(ji)管 3BX31——锗NPN型(xing)(xing)低(di)(di)频(pin)(pin)小(xiao)(xiao)功率(lv)(lv)三极(ji)管 3CD511——硅(gui)PNP型(xing)(xing)低(di)(di)频(pin)(pin)大功率(lv)(lv)三极(ji)管 3DD15——硅(gui)NPN型(xing)(xing)低(di)(di)频(pin)(pin)大功率(lv)(lv)三极(ji)管
2.日(ri)本
由数字(zi)——字(zi)母(mu)-——字(zi)母(mu)——数字(zi)——(字(zi)母(mu))组成
① 第一项数(shu)字表示为:0——光电(dian)晶体管(guan);1——二极管(guan)及整流(liu)器(qi); 2——三极管(guan)及可控整流(liu)器(qi)。
② 第二项(xiang)字母“S”表(biao)示为(wei)半(ban)导体器件。
③ 第三项字(zi)母表示器(qi)件的类型,第一项为0,1的无此第三项。
A——pnp型高频(pin)用 B——PNP型低频(pin)用 C——NPN型高频(pin)用 D——NPN型低频(pin)用
J——P沟道(dao)场(chang)效(xiao)应管(guan) K——N沟道(dao)场(chang)效(xiao)应管(guan)
④第四项数(shu)字(zi)表示登记(ji)序(xu)号。
⑤第五(wu)项字母(mu)在区分原型与变(bian)型时候(hou)使(shi)用(yong),用(yong)字母(mu)A,B,C,D等表示原型的改进型。
例:2SC1815,2SA1015,2SC1942,2SD3298A,2SD1555,2SK134等(deng)。注:日本型号三(san)极管为(wei)了(le)标(biao)记方便常省(sheng)去型号前面(mian)的(de)“2S”,如:A1015,C1815,C3298A,D1555等(deng)。
3. 欧洲
由字(zi)(zi)母——字(zi)(zi)母——数字(zi)(zi)——(字(zi)(zi)母)组(zu)成。
① 第一项(xiang)字母表示(shi)器件所用(yong)的(de)类型。
A——锗材料 B——硅(gui)材料
②第二项字母表示器件的类型。
A——检波(bo),开关,混频(pin)三极管(guan)(guan);B——变容二(er)极管(guan)(guan);C——低(di)频(pin)小功(gong)(gong)率管(guan)(guan);F——高(gao)频(pin)小功(gong)(gong)率管(guan)(guan);D——低(di)频(pin)小功(gong)(gong)率管(guan)(guan);L——高(gao)频(pin)大功(gong)(gong)率管(guan)(guan);S——小功(gong)(gong)率开关管(guan)(guan);U——大功(gong)(gong)率开关管(guan)(guan):E——稳压(ya)管(guan)(guan);Y——整(zheng)流管(guan)(guan)。
③第三项数字表(biao)示登(deng)记(ji)序号。
专用器件用一个字母二位(wei)数字表示登记序号;通用器件三位(wei)数字表示登记序号。
④第四项字母,经(jing)字母A,B,C,D等表示(shi)原型(xing)的改进型(xing)或按某数分(fen)档的标记。
例:BF198——为通用(yong)器(qi)件(jian),硅NPN型(xing)高频小功(gong)率三极(ji)管;BUY71——为专用(yong)器(qi)件(jian),硅NPN型(xing)大功(gong)率开关三极(ji)管。
4. 美(mei)国
由数字(zi)——字(zi)母——数字(zi)——(字(zi)母)组成。
① 第一(yi)项数字及(ji)(ji)第二(er)项字母“N”表(biao)示为:1N——二(er)极(ji)管及(ji)(ji)整流器(qi);2N——三极(ji)管及(ji)(ji)可控(kong)整流器(qi);3N——四(si)极(ji)管。
② 第三项数字表示登记序(xu)号。
③ 第(di)四项字母,用A,B,C,D等(deng)表示原型(xing)的改进型(xing)。例:1N4007,2N3055等(deng)。
5. 韩国三星公(gong)司的数字(zi)三极(ji)管,如:9011,9012,9013,9014,9015,9016,9018等。
集成电(dian)(dian)路(lu)(integratedcircuit,港台称(cheng)之为积(ji)体电(dian)(dian)路(lu))是一种(zhong)微(wei)型(xing)电(dian)(dian)子器件(jian)或部件(jian)。采(cai)用一定的(de)(de)工艺(yi),把一个(ge)电(dian)(dian)路(lu)中所(suo)需的(de)(de)晶体管(guan)、二极管(guan)、电(dian)(dian)阻、电(dian)(dian)容和(he)电(dian)(dian)感等元(yuan)件(jian)及布(bu)线互(hu)连一起,制作(zuo)在(zai)一小块(kuai)或几(ji)小块(kuai)半(ban)导体晶片(pian)或介质基片(pian)上(shang),然(ran)后封装在(zai)一个(ge)管(guan)壳内(nei),成为具有所(suo)需电(dian)(dian)路(lu)功(gong)能的(de)(de)微(wei)型(xing)结构;其中所(suo)有元(yuan)件(jian)在(zai)结构上(shang)已组成一个(ge)整(zheng)体,这(zhei)样,整(zheng)个(ge)电(dian)(dian)路(lu)的(de)(de)体积(ji)大大缩小,且引出线和(he)焊接(jie)点的(de)(de)数目(mu)也大为减少,从而使(shi)电(dian)(dian)子元(yuan)件(jian)向着微(wei)小型(xing)化、低(di)功(gong)耗(hao)和(he)高可靠性方面迈进了一大步(bu)。
集成电路(lu)具有体(ti)积(ji)小(xiao),重量轻(qing),引出线(xian)和(he)焊接点(dian)少,寿命长(zhang),可靠性(xing)高(gao),性(xing)能好等(deng)优点(dian),同时成本低,便于(yu)大规模生产。它不仅在工(gong)、民用(yong)电子设备如收录机、电视机、计算机等(deng)方(fang)面得到(dao)广泛的(de)(de)应用(yong),同时在军事(shi)、通(tong)讯(xun)、遥控(kong)等(deng)方(fang)面也得到(dao)广泛的(de)(de)应用(yong)。用(yong)集成电路(lu)来装配电子设备,其装配密度比晶体(ti)管可提高(gao)几十倍至(zhi)几千倍,设备的(de)(de)稳定工(gong)作时间也可大大提高(gao)。
它在电路(lu)中用(yong)字母“IC”(也有用(yong)文字符号“N”等)表示。
(一)按功能结构(gou)分(fen)类
集成(cheng)电(dian)路按其功能、结构的不同,可以(yi)分为(wei)模拟集成(cheng)电(dian)路、数字集成(cheng)电(dian)路和数/模混合(he)集成(cheng)电(dian)路三(san)大类。
模拟集成电路(lu)又称线性电路(lu),用来(lai)产生、放大和(he)处理各种模拟信(xin)号(hao)(指幅度随时间边疆变化的(de)(de)信(xin)号(hao)。例(li)如半导体收音机(ji)的(de)(de)音频(pin)信(xin)号(hao)、录放机(ji)的(de)(de)磁带(dai)信(xin)号(hao)等),其输入信(xin)号(hao)和(he)输出信(xin)号(hao)成比例(li)关(guan)系。而(er)数(shu)字集成电路(lu)用来(lai)产生、放大和(he)处理各种数(shu)字信(xin)号(hao)(指在时间上和(he)幅度上离(li)散取值的(de)(de)信(xin)号(hao)。例(li)如VCD、DVD重放的(de)(de)音频(pin)信(xin)号(hao)和(he)视(shi)频(pin)信(xin)号(hao))。
(二)按制(zhi)作工(gong)艺分类(lei)
集(ji)成电路按制作(zuo)工艺可分为半导体集(ji)成电路和(he)薄膜集(ji)成电路。
膜(mo)集成(cheng)(cheng)电(dian)路又分类厚(hou)膜(mo)集成(cheng)(cheng)电(dian)路和薄膜(mo)集成(cheng)(cheng)电(dian)路。
(三)按(an)集成度高低分类(lei)
集(ji)成电(dian)路按集(ji)成度(du)高低的不(bu)同可分为小(xiao)规(gui)模(mo)(mo)(mo)(mo)集(ji)成电(dian)路、中规(gui)模(mo)(mo)(mo)(mo)集(ji)成电(dian)路、大(da)规(gui)模(mo)(mo)(mo)(mo)集(ji)成电(dian)路、超大(da)规(gui)模(mo)(mo)(mo)(mo)集(ji)成电(dian)路、特大(da)规(gui)模(mo)(mo)(mo)(mo)集(ji)成电(dian)路和巨大(da)规(gui)模(mo)(mo)(mo)(mo)集(ji)成电(dian)路。
(四)按导(dao)电类型不同(tong)分类
集(ji)成(cheng)(cheng)电(dian)(dian)路(lu)(lu)按导电(dian)(dian)类型(xing)可分为双极(ji)型(xing)集(ji)成(cheng)(cheng)电(dian)(dian)路(lu)(lu)和单极(ji)型(xing)集(ji)成(cheng)(cheng)电(dian)(dian)路(lu)(lu),他们都(dou)是数字(zi)集(ji)成(cheng)(cheng)电(dian)(dian)路(lu)(lu).
双极型集(ji)成(cheng)电(dian)路(lu)的(de)制作(zuo)工(gong)艺(yi)复(fu)杂(za),功(gong)耗较(jiao)(jiao)大(da),代表集(ji)成(cheng)电(dian)路(lu)有(you)TTL、ECL、HTL、LST-TL、STTL等(deng)(deng)类型。单(dan)极型集(ji)成(cheng)电(dian)路(lu)的(de)制作(zuo)工(gong)艺(yi)简单(dan),功(gong)耗也较(jiao)(jiao)低,易于制成(cheng)大(da)规模集(ji)成(cheng)电(dian)路(lu),代表集(ji)成(cheng)电(dian)路(lu)有(you)CMOS、NMOS、PMOS等(deng)(deng)类型。
(五)按用途(tu)分类(lei)
集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)按用(yong)(yong)途可分为电(dian)(dian)(dian)视机用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、音响用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、影碟机用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、录(lu)像机用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、电(dian)(dian)(dian)脑(nao)(微机)用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、电(dian)(dian)(dian)子琴用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、通信用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、照相机用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、遥控集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、语言(yan)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)、报警器用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)及各(ge)种(zhong)专用(yong)(yong)集(ji)成(cheng)(cheng)(cheng)(cheng)(cheng)电(dian)(dian)(dian)路(lu)(lu)。
(六)按应用领域分
集(ji)(ji)成(cheng)电(dian)路(lu)按应(ying)用领(ling)域可分为标准通用集(ji)(ji)成(cheng)电(dian)路(lu)和专用集(ji)(ji)成(cheng)电(dian)路(lu)。
(七)按外形(xing)分
集成电路按外形可分为圆形(金属(shu)外壳晶体管(guan)封装型(xing)(xing),一般适(shi)合用于(yu)大功率)、扁平型(xing)(xing)(稳定性好,体积小)和双列(lie)直插(cha)型(xing)(xing).
①直插式(shi)封装
直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)集(ji)成(cheng)(cheng)(cheng)(cheng)电(dian)路(lu)是(shi)引(yin)(yin)(yin)脚插(cha)(cha)(cha)(cha)(cha)入印制(zhi)板中(zhong),然(ran)后再焊接的(de)一(yi)(yi)种集(ji)成(cheng)(cheng)(cheng)(cheng)电(dian)路(lu)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)形式(shi)(shi)(shi),主要(yao)有(you)单(dan)(dan)列(lie)(lie)(lie)(lie)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)和双列(lie)(lie)(lie)(lie)直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)。其(qi)中(zhong)单(dan)(dan)列(lie)(lie)(lie)(lie)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)有(you)单(dan)(dan)列(lie)(lie)(lie)(lie)直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)(SingleInlinePackage,缩写为(wei)SIP和单(dan)(dan)列(lie)(lie)(lie)(lie)直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)(Zig-ZagInlinePackage,缩写为(wei)ZIP),单(dan)(dan)列(lie)(lie)(lie)(lie)直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)的(de)集(ji)成(cheng)(cheng)(cheng)(cheng)电(dian)路(lu)只有(you)一(yi)(yi)排(pai)引(yin)(yin)(yin)脚,单(dan)(dan)列(lie)(lie)(lie)(lie)曲插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)的(de)集(ji)成(cheng)(cheng)(cheng)(cheng)电(dian)路(lu)一(yi)(yi)排(pai)引(yin)(yin)(yin)脚又(you)分(fen)成(cheng)(cheng)(cheng)(cheng)两排(pai)进(jin)行安(an)装(zhuang)(zhuang)(zhuang)。双列(lie)(lie)(lie)(lie)直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)又(you)称DIP封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)(DualInlinePackage),这种封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)的(de)集(ji)成(cheng)(cheng)(cheng)(cheng)电(dian)路(lu)具有(you)两排(pai)引(yin)(yin)(yin)脚。适合PCB的(de)穿(chuan)孔(kong)安(an)装(zhuang)(zhuang)(zhuang);易于对PCB布线(xian);安(an)装(zhuang)(zhuang)(zhuang)方便。双列(lie)(lie)(lie)(lie)直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)的(de)结构形式(shi)(shi)(shi)主要(yao)有(you)多层陶瓷双列(lie)(lie)(lie)(lie)直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)、单(dan)(dan)层陶瓷双列(lie)(lie)(lie)(lie)直(zhi)(zhi)(zhi)插(cha)(cha)(cha)(cha)(cha)式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)、引(yin)(yin)(yin)线(xian)框架式(shi)(shi)(shi)封(feng)(feng)(feng)装(zhuang)(zhuang)(zhuang)等。
②.贴片封装(zhuang)
随(sui)着生产(chan)(chan)技术的提高,电子产(chan)(chan)品(pin)的体积(ji)越(yue)来越(yue)小(xiao),体积(ji)较大的直插(cha)式封(feng)(feng)装(zhuang)(zhuang)集(ji)成电路(lu)(lu)已(yi)经不能满(man)足需要(yao)。故设计者又(you)研制(zhi)出(chu)一种(zhong)贴(tie)片(pian)封(feng)(feng)装(zhuang)(zhuang)的集(ji)成电路(lu)(lu),这种(zhong)封(feng)(feng)装(zhuang)(zhuang)的集(ji)成电路(lu)(lu)引(yin)脚(jiao)(jiao)很小(xiao),可以直接焊接在印制(zhi)电路(lu)(lu)板的印制(zhi)导线上。贴(tie)片(pian)封(feng)(feng)装(zhuang)(zhuang)的集(ji)成电路(lu)(lu)主要(yao)有薄(bo)(bo)型(xing)(xing)QFP(TQFP)、细引(yin)脚(jiao)(jiao)间距QFP(VQFP)、缩小(xiao)型(xing)(xing)QFP(SQFP)、塑料QFP(PQFP)、金(jin)属QFP(MetalQFP)、载带QFP(TapeQFP)、J型(xing)(xing)引(yin)脚(jiao)(jiao)小(xiao)外(wai)形封(feng)(feng)装(zhuang)(zhuang)(SOJ)、薄(bo)(bo)小(xiao)外(wai)形封(feng)(feng)装(zhuang)(zhuang)(TSOP)、甚小(xiao)外(wai)形封(feng)(feng)装(zhuang)(zhuang)(V S O P)、缩小(xiao)型(xing)(xing)S OP(SSOP)、薄(bo)(bo)的缩小(xiao)型(xing)(xing)SOP(TSSOP)及小(xiao)外(wai)形集(ji)成电路(lu)(lu)(SOIC)等(deng)派生封(feng)(feng)装(zhuang)(zhuang)。
③.BGA封装 (Ball Grid ArrayPackage)
又(you)名(ming)球(qiu)栅(zha)阵列(lie)封装(zhuang)(zhuang),BGA封装(zhuang)(zhuang)的引脚以圆形(xing)(xing)或柱状焊点按阵列(lie)形(xing)(xing)式分布在封装(zhuang)(zhuang)下面。采用该(gai)封装(zhuang)(zhuang)形(xing)(xing)式的集成(cheng)电路主要(yao)有(you)CPU以及(ji)南北(bei)桥等的高密(mi)度、高性能、多功(gong)能集成(cheng)电路。
BGA封装集成(cheng)电路的(de)优点是虽然增(zeng)加(jia)了引脚数,但引脚间距并没有(you)减(jian)(jian)小反而(er)增(zeng)加(jia)了,从而(er)提高了组(zu)装成(cheng)品率(lv);厚度和重(zhong)量(liang)都(dou)较以前的(de)封装技术有(you)所(suo)减(jian)(jian)少;寄生(sheng)参数减(jian)(jian)小,信号(hao)传输(shu)延迟(chi)小,使用(yong)频率(lv)大(da)大(da)提高;组(zu)装可(ke)用(yong)共面焊接(jie),可(ke)靠性高。
④.厚膜封装厚膜
集(ji)成(cheng)电(dian)路就是把专(zhuan)用的(de)(de)集(ji)成(cheng)电(dian)路芯片与相(xiang)关的(de)(de)电(dian)容、电(dian)阻元件都集(ji)成(cheng)在一个基(ji)板上,然后在其外部采用标准的(de)(de)封装形(xing)式,并引出引脚的(de)(de)一种模块(kuai)化的(de)(de)集(ji)成(cheng)电(dian)路。
①测量内(nei)部电阻法
用(yong)万用(yong)表电(dian)(dian)阻档的R×1K档在(zai)IC非在(zai)路的情况(kuang)下测量其各(ge)脚对地或各(ge)脚之间的正反向电(dian)(dian)阻与正常值(zhi)或好的IC比较,在(zai)若电(dian)(dian)阻值(zhi)基(ji)本相同(误差≤±10%)则(ze)可(ke)认为(wei)该IC是好的;若部分或全部脚电(dian)(dian)阻值(zhi)相差过(guo)大则(ze)该IC不良或损坏。
② 测量在路电阻法
用万用表电阻档的(de)R×1K档在电路板上测(ce)量IC各(ge)脚(jiao)(jiao)(jiao)对地(di)(指电路板的(de)地(di)线)的(de)正反向电阻值(zhi)与正常(chang)值(zhi)或(huo)好的(de)电路板比较,若电阻值(zhi)基(ji)本相同(tong)(误差≤±10%)则可(ke)认为该IC是好的(de);若部分(fen)或(huo)全(quan)部脚(jiao)(jiao)(jiao)电阻值(zhi)相差过大,则在检查部分(fen)或(huo)全(quan)部引脚(jiao)(jiao)(jiao)外围电路元件正常(chang)的(de)情况下,则该IC不良或(huo)损(sun)坏。
③ 测量直流工作电压(ya)法
用万用表直流(liu)电(dian)(dian)压(ya)档测量IC各脚对地的(de)(de)直流(liu)工(gong)作电(dian)(dian)压(ya)与正常值(zhi)(zhi)(zhi)或(huo)好的(de)(de)电(dian)(dian)路比较,若电(dian)(dian)压(ya)值(zhi)(zhi)(zhi)基本相同(误差≤±10%)则可(ke)以认为(wei)该IC是好的(de)(de);若电(dian)(dian)压(ya)值(zhi)(zhi)(zhi)误差过大则在检查相应引脚的(de)(de)外围电(dian)(dian)路元件正常的(de)(de)情(qing)况(kuang)下(xia)为(wei)该IC不良或(huo)损坏。
④ 代换(huan)法
在检查集成电(dian)路(lu)(lu)(lu)外(wai)围(wei)元(yuan)件(jian)正(zheng)常(chang)情况下IC却(que)不(bu)能正(zheng)常(chang)工(gong)作,则(ze)(ze)可用一块好的(de)IC代换(huan)(huan)怀(huai)疑已损坏的(de)IC,若(ruo)代换(huan)(huan)后电(dian)路(lu)(lu)(lu)能正(zheng)常(chang)工(gong)作则(ze)(ze)说明原IC是(shi)不(bu)良或损坏;若(ruo)代换(huan)(huan)后电(dian)路(lu)(lu)(lu)还是(shi)不(bu)能正(zheng)常(chang)工(gong)作则(ze)(ze)原IC有(you)可能没有(you)损坏,应继续检查外(wai)围(wei)电(dian)路(lu)(lu)(lu)元(yuan)件(jian)。
俗称喇叭,是一种电(dian)声转(zhuan)换(huan)器件,能把音(yin)频(pin)电(dian)信号转(zhuan)换(huan)为(wei)声音(yin)。
①压(ya)电陶(tao)瓷(ci)喇叭:由压(ya)电(dian)陶瓷片组成,是根据压(ya)电(dian)效(xiao)应原理(li)发声的。
②电动式喇(la)叭:由永久磁铁(tie),音(yin)(yin)圈,纸(zhi)(zhi)盘,振膜等构(gou)成。其发声原理(li)是:根据同性磁极(ji)相互排斥,异性磁极(ji)相互吸引的(de)原理(li),当音(yin)(yin)圈通入音(yin)(yin)频(pin)电信(xin)号时将产(chan)生(sheng)音(yin)(yin)频(pin)电磁场与永久磁铁(tie)上产(chan)生(sheng)的(de)磁场产(chan)生(sheng)相互作用力,于(yu)是音(yin)(yin)圈带动纸(zhi)(zhi)盘运动,从而使纸(zhi)(zhi)盘振动空气发出声音(yin)(yin)。
①功率:分为最(zui)小功率和最(zui)大功率两(liang)种
最小功(gong)(gong)率(PMIN):又叫(jiao)不失真功(gong)(gong)率,指失真度在额定范围的功(gong)(gong)率。
最(zui)大功(gong)(gong)率(PMAX):又叫峰(feng)值功(gong)(gong)率,指喇(la)叭所(suo)能承(cheng)受的(de)最(zui)大功(gong)(gong)率。
②阻抗:指(zhi)喇叭对音(yin)频电信(xin)号的等(deng)效电阻。阻抗=音(yin)圈的直流电阻+音(yin)圈感抗。
③频率特性:指喇(la)叭重(zhong)放(fang)声音(yin)的频(pin)率范围(wei),全音(yin)域高音(yin),中音(yin),低音(yin)等。声音(yin)的频(pin)率范围(wei)为20Hz——20KHz。
④口径:指(zhi)喇叭(ba)纸盘的直(zhi)径。
用万用表电(dian)阻档的(de)(de)1Ω档可粗略判断喇(la)叭(ba)的(de)(de)好坏(huai)(huai)。方法是:测试音(yin)圈的(de)(de)直(zhi)流(liu)电(dian)阻应(ying)略小于(yu)喇(la)叭(ba)的(de)(de)阻抗值且测试时(shi)喇(la)叭(ba)应(ying)能发出“喀嚓”声为(wei)正常,若有直(zhi)流(liu)电(dian)阻过小则音(yin)圈短路损坏(huai)(huai),若电(dian)阻值为(wei)无穷大则音(yin)圈已开路损坏(huai)(huai),同时(shi)用手轻按纸盘(pan)应(ying)弹性良(liang)好,不能有杂音(yin),否则该喇(la)叭(ba)也不良(liang)。
① 从喇叭接线柱可(ke)直接看出,有加号(+)的为正相位(wei),减号(-)为负相位(wei)。
③用(yong)万用(yong)表(biao)直流电压(ya)(电流)档的最低量程档(如:0.5V档)红黑表(biao)笔分别接喇叭(ba)接线(xian)柱两端,再用(yong)手轻轻按(an)下纸盘,若表(biao)针会轻微向右摆动则表(biao)笔极性(xing)刚好相(xiang)反。
①扬声(sheng)器有故(gu)障(zhang)时建(jian)议更换(huan)一个(ge)同型号的(de)新扬声(sheng)器解(jie)决,但(dan)在没有新的(de)扬声(sheng)器更换(huan)或(huo)想(xiang)降低(di)修复成本时也(ye)可对其进行修理。
②音圈引(yin)出线(xian)(xian)(xian)折(zhe)断(duan)(duan)的(de)(de)修(xiu)理:扬声器使用(yong)日久或引(yin)线(xian)(xian)(xian)质量太差时,由于纸盘的(de)(de)振(zhen)动而极易(yi)引(yin)起音圈引(yin)出线(xian)(xian)(xian)折(zhe)断(duan)(duan),此时可(ke)用(yong)相同或相近(jin)的(de)(de)喇(la)叭专用(yong)的(de)(de)编织软线(xian)(xian)(xian)更(geng)换即可(ke)修(xiu)复。注:请不(bu)要用(yong)其它硬(ying)线(xian)(xian)(xian)或花线(xian)(xian)(xian)来(lai)更(geng)换,否则不(bu)但(dan)音质受(shou)影响而且引(yin)出线(xian)(xian)(xian)也(ye)很易(yi)再次(ci)折(zhe)断(duan)(duan)。
③若为(wei)音(yin)(yin)圈(quan)损坏时(shi)(shi),则应用ΩΩ天那水(香蕉水)浸开防尘罩及旧音(yin)(yin)圈(quan)再用同(tong)型号音(yin)(yin)圈(quan)(也可以自(zi)行绕制(zhi))更换来修(xiu)复(fu),更换音(yin)(yin)圈(quan)等应按原来音(yin)(yin)圈(quan)的位(wei)置(zhi)来用粘(zhan)(zhan)合(he)(he)剂粘(zhan)(zhan)固(gu)新音(yin)(yin)圈(quan),若难以分(fen)别原位(wei)置(zhi)时(shi)(shi),也可以先装入(ru)(ru)音(yin)(yin)圈(quan)连线(xian)再通入(ru)(ru)声音(yin)(yin)信(xin)号调整音(yin)(yin)圈(quan)的位(wei)置(zhi)使声音(yin)(yin)最(zui)大音(yin)(yin)质最(zui)好然后用粘(zhan)(zhan)合(he)(he)剂粘(zhan)(zhan)固(gu)凉干(gan)后即可修(xiu)复(fu)。
④若纸盘(pan)损(sun)(sun)破(po)时(shi)可(ke)用相同纸盘(pan)材料(liao)修(xiu)补(bu)破(po)损(sun)(sun)处即可(ke)修(xiu)复,若纸盘(pan)损(sun)(sun)破(po)严重时(shi)则(ze)只能(neng)换一个新纸盘(pan)解决。
⑤若铁(tie)芯与永久磁铁(tie)松动移(yi)位导致与音圈相(xiang)碰时,在业余条件下一(yi)般难以修复而建议更换一(yi)个新扬声(sheng)器(qi)解决。
⑥对于(yu)球顶高音(yin)(yin)喇叭,由于(yu)音(yin)(yin)圈(quan)与纸盘(pan)(振膜)为(wei)一个整体,若音(yin)(yin)圈(quan)损坏时(shi),则拆(chai)开(kai)旧音(yin)(yin)圈(quan)总成(cheng)来更换一个新的音(yin)(yin)圈(quan)吝惜成(cheng)即可(其修理最简单)。
1.晶体(ti):又叫晶(jing)振,晶(jing)体振荡(dang)器(qi),谐振器(qi)等。由(you)石英晶(jing)片或(huo)压电陶瓷片组成,常(chang)用于振荡(dang)电路中。
2.滤波器:常见有晶体滤波器(qi)和陶瓷滤波器(qi),用(yong)于对某一频率的(de)信(xin)号进行(xing)选频或滤除。
3.声(sheng)表面(mian)滤波器:由叉指换能器组成的
指由多个相同或不同器(qi)件(jian)制造或组合在一起的器(qi)件(jian),称为复合器(qi)件(jian)。
采用多个阻值完全相同的(de)电(dian)阻把一端(duan)(duan)并接(jie)在一起作为公共端(duan)(duan)构成的(de)电(dian)阻排。
采用多个容量完全相同(tong)的单(dan)体电容把其一(yi)端并接起来(lai)作为公共端构成的电容排(pai)或者在同(tong)一(yi)制造中封装(zhuang)在一(yi)起构成。
指把多(duo)个电感线圈(quan)与电容按一(yi)定连(lian)接(jie)方式连(lian)接(jie)在(zai)一(yi)起(qi)构成,多(duo)用于滤(lv)波器(qi)。
由两个(ge)整流二(er)极管封装(zhuang)在一起构成(cheng),多(duo)用于整流电路等。
简称桥堆,由四(si)个(ge)整(zheng)(zheng)流(liu)二(er)极管(guan)按一定方(fang)式(shi)连接在一起构成(cheng),常(chang)用于整(zheng)(zheng)流(liu)电路中。
指基极(ji)(ji)与发(fa)射极(ji)(ji)之间接有分压电阻的(de)三极(ji)(ji)管(guan)。
由两个(ge)三(san)极管(guan)复(fu)合而成,复(fu)合管的(de)极性与前(qian)管极性相(xiang)同,复合管的(de)放大倍(bei)数为两管放大倍(bei)数乘积。
把一个发光(guang)二极(ji)管和一个光(guang)敏三(san)极(ji)管封装在一起构成(cheng)光(guang)电耦合器。
常见有四脚(jiao)光电耦合(he)器(qi)和六(liu)脚(jiao)光电耦合(he)器(qi)
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