本文將對開關電源中恒電流源電路的工作原理及特點等進(jin)行(xing)分析，供讀者。

　　一、開關電源恒流源電路的(de)(de)(de)(de)(de)(de)(de)(de)構成(cheng)(cheng)(cheng)及工(gong)作(zuo)(zuo)原理由分立(li)元(yuan)件組(zu)成(cheng)(cheng)(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)開(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)中的(de)(de)(de)(de)(de)(de)(de)(de)恒流(liu)(liu)源(yuan)(yuan)電(dian)(dian)(dian)路(lu)(lu)由分立(li)元(yuan)件組(zu)成(cheng)(cheng)(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)開(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)采(cai)用恒流(liu)(liu)源(yuan)(yuan)電(dian)(dian)(dian)路(lu)(lu)的(de)(de)(de)(de)(de)(de)(de)(de)彩電(dian)(dian)(dian)有：長(chang)虹NC-2、NC- 3、A6等機心系列闈電(dian)(dian)(dian)。另外，東芝2929DH/DXH彩3開(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)基(ji)本相同，也(ye)是采(cai)用恒流(liu)(liu)源(yuan)(yuan)電(dian)(dian)(dian)揠。，是這種開(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)中的(de)(de)(de)(de)(de)(de)(de)(de)振(zhen)蕩和(he)恒流(liu)(liu)源(yuan)(yuan)原理圖。振(zhen)蕩‘路(lu)(lu)由-⑨繞(rao)組(zu)是振(zhen)蕩電(dian)(dian)(dian)路(lu)(lu)的(de)(de)(de)(de)(de)(de)(de)(de)反饋(kui)支路(lu)(lu)。恒流(liu)(liu)源(yuan)(yuan)由VQ820、R822、VD820、C821、R823、T803⑦~⑧和(he)⑦⑨繞(rao)組(zu)構成(cheng)(cheng)(cheng)。其(qi)(qi)工(gong)作(zuo)(zuo)原理是：在VQ83截(jie)(jie)止(zhi)期間，T803的(de)(de)(de)(de)(de)(de)(de)(de)⑧端電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)為(wei)正(zheng)(zheng)，⑨端電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)為(wei)負(fu)。⑨端的(de)(de)(de)(de)(de)(de)(de)(de)負(fu)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)經(jing)R823加(jia)到(dao)VQ820的(de)(de)(de)(de)(de)(de)(de)(de)基(ji)極，使(shi)VQ820截(jie)(jie)止(zhi)。T803⑧端的(de)(de)(de)(de)(de)(de)(de)(de)正(zheng)(zheng)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)通過(guo)VD820向(xiang)C821充(chong)電(dian)(dian)(dian)，C821上(shang)充(chong)得的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)就成(cheng)(cheng)(cheng)為(wei)VQ820導通時(shi)所(suo)需的(de)(de)(de)(de)(de)(de)(de)(de)工(gong)作(zuo)(zuo)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)。VQ83導通時(shi)，T803⑧端電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)變(bian)負(fu)，⑨端電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)由負(fu)變(bian)正(zheng)(zheng)。⑧端的(de)(de)(de)(de)(de)(de)(de)(de)負(fu)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)加(jia)到(dao)VD820正(zheng)(zheng)極使(shi)其(qi)(qi)截(jie)(jie)止(zhi)，⑨端的(de)(de)(de)(de)(de)(de)(de)(de)正(zheng)(zheng)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)經(jing)R823加(jia)到(dao)VQ820基(ji)極使(shi)其(qi)(qi)導通。VQ820導通后(hou)，流(liu)(liu)經(jing)VQ820集(ji)-射之間的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)流(liu)(liu)便成(cheng)(cheng)(cheng)為(wei)VQ83的(de)(de)(de)(de)(de)(de)(de)(de)基(ji)極注人電(dian)(dian)(dian)流(liu)(liu)。VQ820的(de)(de)(de)(de)(de)(de)(de)(de)導通電(dian)(dian)(dian)流(liu)(liu)不受交流(liu)(liu)輸(shu)人電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)波動的(de)(de)(de)(de)(de)(de)(de)(de)影響(xiang)，其(qi)(qi)大(da)小取(qu)決于C821上(shang)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)和(he)電(dian)(dian)(dian)阻R822的(de)(de)(de)(de)(de)(de)(de)(de)大(da)小，所(suo)以，VQ83的(de)(de)(de)(de)(de)(de)(de)(de)基(ji)極電(dian)(dian)(dian)流(liu)(liu)同樣不受交流(liu)(liu)電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)波動的(de)(de)(de)(de)(de)(de)(de)(de)影響(xiang)，這就展寬了開(kai)關(guan)電(dian)(dian)(dian)源(yuan)(yuan)對交流(liu)(liu)輸(shu)入電(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)(de)(de)(de)(de)(de)(de)(de)適(shi)應范圍。

　　恒(heng)流(liu)(liu)源(yuan)電(dian)路6333等。采用STR-S6309組成開關(guan)電(dian)源(yuan)的彩(cai)電(dian)有：康佳06系列），夏普25N42-E2、29FN1、29AW1及寬(kuan)屏W288、W328，熊(xiong)貓(mao)C64P2、2919，長城G8173MF、G8263、G8363，創(chuang)維CTV-8259、CTV-8298.厚(hou)膜電(dian)路STR-S6308與STR-S6309內部電(dian)路結構(gou)基本相(xiang)同，恒(heng)流(liu)(liu)源(yuan)電(dian)路和(he)原理(li)完全相(xiang)同。下面以STR-S6308厚(hou)膜電(dian)路組成的開關(guan)電(dian)源(yuan)為例說明(ming)其恒(heng)流(liu)(liu)源(yuan)工(gong)作(zuo)原理(li)。

　　是STR-6308厚膜(mo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)組(zu)成的(de)(de)(de)(de)(de)(de)(de)開(kai)(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)中的(de)(de)(de)(de)(de)(de)(de)振蕩(dang)和(he)恒(heng)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)原(yuan)理圖。圖中，IC801內部(bu)的(de)(de)(de)(de)(de)(de)(de)Q1是開(kai)(kai)關管(guan)(guan)，R803、R804是振蕩(dang)啟(qi)動電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，C812、R807、T803①-②繞組(zu)是振蕩(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)的(de)(de)(de)(de)(de)(de)(de)反(fan)饋支路(lu)(lu)。恒(heng)流(liu)(liu)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)由IC801內部(bu)的(de)(de)(de)(de)(de)(de)(de)Q3、R2、R3、D2及外部(bu)的(de)(de)(de)(de)(de)(de)(de)C814、D803、R806和(he)T803①-②繞組(zu)構成。其(qi)恒(heng)流(liu)(liu)源(yuan)工(gong)作原(yuan)理為(wei)：在(zai)（1截止期間，T803②端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)為(wei)正(zheng)，①端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)為(wei)負(fu)。T803②端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)通過IC801內部(bu)的(de)(de)(de)(de)(de)(de)(de)D2向C814充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，其(qi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)路(lu)(lu)徑為(wei)：T803②④一(yi)814-803-803①。C814上(shang)充(chong)得的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)就(jiu)成為(wei)Q3導(dao)通時所(suo)需要的(de)(de)(de)(de)(de)(de)(de)工(gong)作電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。在(zai)Q1導(dao)通時，T803②端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)由正(zheng)變(bian)負(fu)，①端(duan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)由負(fu)變(bian)正(zheng)。②端(duan)的(de)(de)(de)(de)(de)(de)(de)負(fu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)加(jia)到(dao)(dao)D2的(de)(de)(de)(de)(de)(de)(de)正(zheng)極(ji)使其(qi)截止，①端(duan)的(de)(de)(de)(de)(de)(de)(de)正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)加(jia)到(dao)(dao)IC801的(de)(de)(de)(de)(de)(de)(de)⑤腳，再通過其(qi)內部(bu)R3加(jia)到(dao)(dao)Q3的(de)(de)(de)(de)(de)(de)(de)基極(ji)使其(qi)導(dao)通。Q3導(dao)通后，C814通過Q3放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，其(qi)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)路(lu)(lu)徑為(wei)：C814正(zheng)極(ji)->IC801dH3ce極(ji)->Qlbe極(ji)―IC801②―R806->C814負(fu)極(ji)。Q3導(dao)通后，流(liu)(liu)過Q3集射之間的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)便成為(wei)（1的(de)(de)(de)(de)(de)(de)(de)基極(ji)注人電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。因為(wei)Q3的(de)(de)(de)(de)(de)(de)(de)導(dao)通電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)不(bu)受(shou)交(jiao)流(liu)(liu)輸人電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)波動的(de)(de)(de)(de)(de)(de)(de)影響(xiang)，只取決于C814上(shang)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻R806的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻大(da)小(xiao)，所(suo)以(yi)，開(kai)(kai)關管(guan)(guan)Q1的(de)(de)(de)(de)(de)(de)(de)基極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)同樣(yang)不(bu)受(shou)交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)波動的(de)(de)(de)(de)(de)(de)(de)影響(xiang)，這就(jiu)展寬(kuan)了開(kai)(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)海(hai)對交(jiao)流(liu)(liu)輸人電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)(de)(de)(de)(de)適應范圍。

　　二、開(kai)(kai)關(guan)(guan)(guan)中楦流(liu)(liu)源(yuan)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)的(de)特點1.含(han)恒(heng)流(liu)(liu)源(yuan)的(de)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)與不(bu)含(han)恒(heng)流(liu)(liu)源(yuan)的(de)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)的(de)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)區別通(tong)過對(dui)含(han)恒(heng)流(liu)(liu)源(yuan)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)和(he)不(bu)含(han)恒(heng)流(liu)(liu)源(yuan)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)的(de)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)對(dui)比，就(jiu)會(hui)發(fa)現，這兩類(lei)電(dian)(dian)(dian)(dian)(dian)源(yuan)的(de)振蕩(dang)反(fan)(fan)(fan)饋(kui)支(zhi)路(lu)(lu)的(de)阻(zu)抗(kang)是(shi)不(bu)同的(de)（反(fan)(fan)(fan)饋(kui)支(zhi)路(lu)(lu)主要由電(dian)(dian)(dian)(dian)(dian)阻(zu)和(he)電(dian)(dian)(dian)(dian)(dian)容(rong)串聯(lian)組成）。附表是(shi)這兩類(lei)電(dian)(dian)(dian)(dian)(dian)源(yuan)幾種機(ji)心彩電(dian)(dian)(dian)(dian)(dian)反(fan)(fan)(fan)饋(kui)電(dian)(dian)(dian)(dian)(dian)容(rong)和(he)反(fan)(fan)(fan)饋(kui)電(dian)(dian)(dian)(dian)(dian)阻(zu)的(de)統計(ji)表。從統計(ji)表中可以(yi)看出：含(han)恒(heng)流(liu)(liu)源(yuan)的(de)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)振蕩(dang)反(fan)(fan)(fan)饋(kui)電(dian)(dian)(dian)(dian)(dian)容(rong)小，阻(zu)抗(kang)大，反(fan)(fan)(fan)饋(kui)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)小；不(bu)含(han)恒(heng)流(liu)(liu)源(yuan)的(de)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)振蕩(dang)反(fan)(fan)(fan)饋(kui)電(dian)(dian)(dian)(dian)(dian)容(rong)大，阻(zu)抗(kang)小，反(fan)(fan)(fan)饋(kui)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)大。

　　2.失效(xiao)后(hou)機器的(de)(de)(de)故障表現開(kai)關(guan)電(dian)源中(zhong)(zhong)的(de)(de)(de)恒流電(dian)路(lu)失效(xiao)后(hou)，注(zhu)人開(kai)關(guan)管的(de)(de)(de)基極電(dian)流僅(jin)有振蕩(dang)反(fan)饋支(zhi)路(lu)一(yi)路(lu)電(dian)流，只能維持開(kai)關(guan)管處(chu)于(yu)弱振蕩(dang)狀態(tai)，開(kai)關(guan)電(dian)源的(de)(de)(de)負載能力將會大大降低。遙控彩電(dian)在待(dai)電(dian)子(zi)世界老式(shi)彩電(dian)加裝(zhuang)(zhuang)哞技(ji)討(tao)嫡t媒葙(xiang)f鯰改良方(fang)鉉李超2.記錄數據安裝(zhuang)(zhuang)前(qian)測(ce)量(liang)(liang)并記錄彩電(dian)各模擬量(liang)(liang)的(de)(de)(de)電(dian)壓(ya)調(diao)節板±的(de)(de)(de)運(yun)放。農彩電(dian)中(zhong)(zhong)模擬量(liang)(liang)控制電(dian)壓(ya)的(de)(de)(de)兩(liang)個指標彩電(dian)中(zhong)(zhong)有音量(liang)(liang)、亮(liang)度等模擬量(liang)(liang)控制電(dian)路(lu)，它們一(yi)般用調(diao)節電(dian)壓(ya)的(de)(de)(de)方(fang)式(shi)進行控制。在這種電(dian)路(lu)中(zhong)(zhong)，控制電(dian)壓(ya)有兩(liang)個指標。

　　調節(jie)范圍設(she)電位器調到上、下(xia)極限時，對應的觸頭電位分別(bie)為Vh、Vl，則(ze)控(kong)制電壓調節(jie)范圍AV=VH―VL.一般來說厶V越大控(kong)制范圍越寬。但(dan)是，過大的AV會使(shi)調節(jie)精度(du)下(xia)降(jiang)，影響圖像(xiang)或伴音質量，嚴重時彩電不(bu)能正常工作。

　　平均(jun)電位平均(jun)電位丫(ya)=丫(ya)11一￥1/2.丫(ya)的大小(xiao)直接影(ying)響控(kong)(kong)制(zhi)效果。如飽(bao)和度控(kong)(kong)制(zhi)中(zhong)，V過小(xiao)會造成圖像(xiang)飽(bao)和度調不起(qi)來，色彩很淡(dan)。所以在(zai)加裝遙控(kong)(kong)時(shi)，AV和V應(ying)盡可能調整到設計水平。如有困難，以適當偏高為宜。

　　改良方法的(de)基本構想1.模擬(ni)(ni)量(liang)控(kong)(kong)制(zhi)(zhi)電(dian)路的(de)特(te)點老式彩電(dian)一般有四個模擬(ni)(ni)量(liang)，如遙控(kong)(kong)板上有四個相應(ying)的(de)模擬(ni)(ni)量(liang)輸出(chu)電(dian)路，各(ge)由三只電(dian)阻(zu)：輸出(chu)電(dian)阻(zu)，上、下偏置(zhi)電(dian)阻(zu)組成，在(zai)中(zhong)相應(ying)的(de)電(dian)阻(zu)分別(bie)是R17、R18、R19.其中(zhong)，輸出(chu)電(dian)阻(zu)主(zhu)要控(kong)(kong)制(zhi)(zhi)調節(jie)范圍，上、下偏置(zhi)電(dian)阻(zu)主(zhu)要控(kong)(kong)制(zhi)(zhi)平均電(dian)位。

　　2.現行的(de)(de)(de)調整(zheng)方(fang)法及改良安裝說明書及一般(ban)資料(liao)上(shang)介(jie)紹的(de)(de)(de)方(fang)法是，廢(fei)除彩電(dian)(dian)原(yuan)有的(de)(de)(de)分壓調節電(dian)(dian)路，對遙控板上(shang)的(de)(de)(de)電(dian)(dian)阻(zu)進行調整(zheng)。這(zhe)樣須調整(zheng)的(de)(de)(de)電(dian)(dian)阻(zu)一般(ban)有12只(zhi)。在實際工作中(zhong)要選定(ding)并(bing)找到(dao)相應的(de)(de)(de)電(dian)(dian)阻(zu)并(bing)不容易，調整(zheng)起來反(fan)反(fan)復復，耗時多，精度差(cha)。

　　從上(shang)面的(de)分析中(zhong)，我們(men)不難發現：如(ru)果保留彩電(dian)上(shang)的(de)分壓(ya)電(dian)路就可以省掉遙(yao)控板上(shang)的(de)分壓(ya)電(dian)路，這(zhe)樣(yang)需調整(zheng)的(de)電(dian)阻由12只減為4只，大大減少(shao)了工(gong)作量，有(you)利于提高調整(zheng)精度。

　　實例-1803PD（S）彩(cai)電(dian)(dian)(dian)(dian)安裝卓異Z9831遙(yao)控(kong)器為例，現(xian)介紹如下：1.準(zhun)備(bei)材料找51kn、200kfl可(ke)調電(dian)(dian)(dian)(dian)阻各(ge)一(yi)只，按連接(jie)，引(yin)線長約30cm.備(bei)1/8W電(dian)(dian)(dian)(dian)阻若(ruo)干。機狀(zhuang)態(tai)(tai)，行(xing)、場(chang)掃(sao)(sao)描(miao)(miao)電(dian)(dian)(dian)(dian)路停(ting)(ting)止工(gong)作(zuo)(zuo)(zuo)，開(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)(yuan)處于輕負(fu)荷狀(zhuang)態(tai)(tai)，即(ji)使恒流有問題(ti)也看不出(chu)它的(de)故(gu)障表現(xian)。當(dang)電(dian)(dian)(dian)(dian)視機處于正常收視狀(zhuang)態(tai)(tai)，特別是電(dian)(dian)(dian)(dian)視屏幕比較(jiao)亮(liang)時(shi)，行(xing)、場(chang)掃(sao)(sao)描(miao)(miao)系(xi)統要消耗較(jiao)大的(de)功率，恒流源(yuan)(yuan)失效(xiao)了的(de)開(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)(yuan)難以(yi)負(fu)擔這一(yi)重任，開(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)(yuan)將會停(ting)(ting)止工(gong)作(zuo)(zuo)(zuo)。開(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)(yuan)停(ting)(ting)止工(gong)作(zuo)(zuo)(zuo)后，行(xing)、場(chang)掃(sao)(sao)描(miao)(miao)電(dian)(dian)(dian)(dian)路因(yin)(yin)失去(qu)供(gong)電(dian)(dian)(dian)(dian)也自然停(ting)(ting)止工(gong)作(zuo)(zuo)(zuo)，這時(shi)開(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)(yuan)因(yin)(yin)失去(qu)負(fu)載(zai)又開(kai)(kai)(kai)始起振工(gong)作(zuo)(zuo)(zuo)，行(xing)、場(chang)掃(sao)(sao)描(miao)(miao)又得到供(gong)電(dian)(dian)(dian)(dian)再度工(gong)作(zuo)(zuo)(zuo)，開(kai)(kai)(kai)關(guan)(guan)管負(fu)擔加重又停(ting)(ting)止工(gong)作(zuo)(zuo)(zuo)，周而復始，范(fan)圍(wei)，留作(zuo)(zuo)(zuo)調試(shi)標準(zhun)。實測數據為：亮(liang)度：7.4彩(cai)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)路改動關(guan)(guan)掉彩(cai)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)源(yuan)(yuan)拔(ba)下插頭，將各(ge)模擬量的(de)控(kong)制端由電(dian)(dian)(dian)(dian)位(wei)器的(de)中(zhong)心抽頭改接(jie)到電(dian)(dian)(dian)(dian)位(wei)器的(de)高電(dian)(dian)(dian)(dian)位(wei)端，并與遙(yao)控(kong)板上(shang)相(xiang)應模擬量的(de)輸出(chu)引(yin)線庫(ku)接(jie)，如所(suo)示(shi)。

　　4遙(yao)控板調(diao)(diao)整(zheng)拔(ba)下(xia)遙(yao)控板上(shang)(shang)各(ge)模擬(ni)量輸(shu)出(chu)(chu)端(duan)的(de)上(shang)(shang)下(xia)偏(pian)置電(dian)阻(zu)共8只，在其(qi)它加(jia)裝工(gong)作已完成的(de)情況下(xia)，對各(ge)模擬(ni)量的(de)輸(shu)出(chu)(chu)電(dian)阻(zu)進(jin)行調(diao)(diao)整(zheng)。以(yi)亮(liang)(liang)度控制(zhi)為例，具體(ti)步驟如下(xia)：⑴拔(ba)下(xia)輸(shu)出(chu)(chu)電(dian)阻(zu)R17，將(jiang)(jiang)51M1可(ke)調(diao)(diao)電(dian)阻(zu)焊(han)上(shang)(shang)，通電(dian)并用(yong)遙(yao)控將(jiang)(jiang)亮(liang)(liang)度調(diao)(diao)到(dao)最小。如果(guo)熒光屏不亮(liang)(liang)，可(ke)用(yong)萬(wan)用(yong)表監測亮(liang)(liang)度控制(zhi)電(dian)壓(ya)，下(xia)降到(dao)不動為止。

　　（2）調(diao)(diao)整51kfi可(ke)(ke)(ke)調(diao)(diao)電(dian)(dian)阻(zu)使亮度控制電(dian)(dian)壓為7.4V.關機(ji)焊(han)下可(ke)(ke)(ke)調(diao)(diao)電(dian)(dian)阻(zu)的一(yi)端，測(ce)得其阻(zu)值(zhi)(zhi)為37kfl.⑶重(zhong)新焊(han)上可(ke)(ke)(ke)調(diao)(diao)電(dian)(dian)阻(zu)并開機(ji)，用(yong)遙控器將亮度調(diao)(diao)到最大。調(diao)(diao)整可(ke)(ke)(ke)調(diao)(diao)電(dian)(dian)阻(zu)使亮度控制電(dian)(dian)壓為7.9V，關機(ji)焊(han)下可(ke)(ke)(ke)調(diao)(diao)電(dian)(dian)阻(zu)，測(ce)得其阻(zu)值(zhi)(zhi)為40kft.在步驟⑵、⑶中。如果調(diao)(diao)整可(ke)(ke)(ke)調(diao)(diao)電(dian)(dian)阻(zu)達不到所需電(dian)(dian)壓，就將可(ke)(ke)(ke)調(diao)(diao)電(dian)(dian)阻(zu)由51kfl換成200M1后重(zhong)試。

　　⑷一般來說(shuo)，選擇偏小的(de)(de)輸(shu)出(chu)電阻使(shi)調節范圍適當擴(kuo)大為(wei)宜，這(zhe)里(li)(li)選R17=36kft.經測試亮度(du)控制電壓為(wei)7.3~8.IV，效(xiao)果(guo)(guo)很理(li)想。如果(guo)(guo)選R17=33kft，效(xiao)果(guo)(guo)也不錯。其它三個模擬量輸(shu)出(chu)電阻的(de)(de)選擇方法與(yu)此相(xiang)同(tong)，這(zhe)里(li)(li)不再贅述。

　　從上面的(de)(de)介紹中不(bu)難(nan)發現(xian)這(zhe)種方法有(you)三個優點：（1）不(bu)需對電(dian)(dian)(dian)路(lu)進(jin)(jin)行(xing)(xing)太多分析和(he)了解(jie)。⑵需要調(diao)(diao)整電(dian)(dian)(dian)阻(zu)由12只變(bian)成(cheng)4只，減(jian)少了工作量(liang)。⑶調(diao)(diao)整精度(du)便于控(kong)(kong)制，有(you)利(li)于提高圖(tu)(tu)像質量(liang)。必(bi)須說(shuo)明(ming)的(de)(de)是，這(zhe)里(li)介紹的(de)(de)；1一般性的(de)(de)方法，在實際(ji)工作中應靈活運用。例(li)如，在對本例(li)的(de)(de)音量(liang)控(kong)(kong)制電(dian)(dian)(dian)路(lu)進(jin)(jin)行(xing)(xing)連接(jie)時(shi)，可(ke)(ke)將遙控(kong)(kong)板上的(de)(de)三只電(dian)(dian)(dian)阻(zu)R11、R12、R13拔(ba)掉，將電(dian)(dian)(dian)視(shi)機中的(de)(de)R302移(yi)到(dao)遙控(kong)(kong)板上R11的(de)(de)位置，如所示，則音量(liang)控(kong)(kong)制電(dian)(dian)(dian)壓(ya)為0~5.6V，效果不(bu)錯。對于控(kong)(kong)制電(dian)(dian)(dian)壓(ya)為0~12V的(de)(de)電(dian)(dian)(dian)路(lu)，如夏(xia)普(pu)NC-2T的(de)(de)色度(du)和(he)對比度(du)控(kong)(kong)制電(dian)(dian)(dian)路(lu)，可(ke)(ke)將遙控(kong)(kong)板輸出(chu)端的(de)(de)上、下偏置電(dian)(dian)(dian)阻(zu)拔(ba)掉，將輸出(chu)電(dian)(dian)(dian)阻(zu)換成(cheng)l~2kft即可(ke)(ke)使用。這(zhe)時(shi)輸出(chu)電(dian)(dian)(dian)阻(zu)僅起限流(liu)作用，以保護遙控(kong)(kong)開關(guan)電(dian)(dian)(dian)源只能(neng)處于間(jian)歇振蕩狀態。表(biao)現(xian)在電(dian)(dian)(dian)視(shi)屏幕上的(de)(de)故(gu)障(zhang)現(xian)象是：電(dian)(dian)(dian)視(shi)屏幕亮(liang)度(du)高時(shi)，光(guang)柵(zha)會(hui)(hui)(hui)不(bu)斷地收(shou)縮(suo)。或(huo)者當電(dian)(dian)(dian)視(shi)畫(hua)(hua)面較暗(an)時(shi)，圖(tu)(tu)像尚(shang)能(neng)穩定住。當電(dian)(dian)(dian)視(shi)畫(hua)(hua)面較亮(liang)時(shi)，就會(hui)(hui)(hui)出(chu)現(xian)“光(guang)柵(zha)不(bu)停(ting)地收(shou)縮(suo)――展(zhan)開一收(shou)縮(suo)”。這(zhe)時(shi)你測(ce)量(liang)+B115V電(dian)(dian)(dian)壓(ya)，在光(guang)柵(zha)收(shou)縮(suo)瞬間(jian)會(hui)(hui)(hui)降至70V左(zuo)右(you)。該(gai)電(dian)(dian)(dian)視(shi)機在調(diao)(diao)機進(jin)(jin)行(xing)(xing)搜(sou)(sou)(sou)索時(shi)，搜(sou)(sou)(sou)索到(dao)的(de)(de)圖(tu)(tu)像比較暗(an)時(shi)，可(ke)(ke)以正常搜(sou)(sou)(sou)索并存(cun)(cun)儲(chu)。搜(sou)(sou)(sou)索到(dao)的(de)(de)圖(tu)(tu)像較亮(liang)時(shi)，光(guang)柵(zha)來回閃動，圖(tu)(tu)像不(bu)穩定，或(huo)同步不(bu)良，電(dian)(dian)(dian)視(shi)頻道不(bu)能(neng)存(cun)(cun)儲(chu)。

                                                                                                                   本文摘自于中國鋰電網(wang)