本文將對開關電(dian)(dian)源(yuan)(yuan)中(zhong)恒電(dian)(dian)流(liu)源(yuan)(yuan)電(dian)(dian)路(lu)的工(gong)作原理及(ji)特點等進行分析，供讀者。

　　一、開關電源恒流源電路的(de)(de)(de)(de)構(gou)成及工作原理由分立(li)元件組(zu)成的(de)(de)(de)(de)開(kai)關電(dian)(dian)(dian)(dian)源(yuan)中(zhong)的(de)(de)(de)(de)恒(heng)(heng)流(liu)(liu)(liu)源(yuan)電(dian)(dian)(dian)(dian)路(lu)(lu)由分立(li)元件組(zu)成的(de)(de)(de)(de)開(kai)關電(dian)(dian)(dian)(dian)源(yuan)采用恒(heng)(heng)流(liu)(liu)(liu)源(yuan)電(dian)(dian)(dian)(dian)路(lu)(lu)的(de)(de)(de)(de)彩電(dian)(dian)(dian)(dian)有：長虹NC-2、NC- 3、A6等機心(xin)系列闈電(dian)(dian)(dian)(dian)。另外，東芝2929DH/DXH彩3開(kai)關電(dian)(dian)(dian)(dian)源(yuan)基(ji)(ji)(ji)本相同(tong)，也是(shi)采用恒(heng)(heng)流(liu)(liu)(liu)源(yuan)電(dian)(dian)(dian)(dian)揠。，是(shi)這(zhe)種開(kai)關電(dian)(dian)(dian)(dian)源(yuan)中(zhong)的(de)(de)(de)(de)振蕩和(he)恒(heng)(heng)流(liu)(liu)(liu)源(yuan)原理圖(tu)。振蕩‘路(lu)(lu)由-⑨繞組(zu)是(shi)振蕩電(dian)(dian)(dian)(dian)路(lu)(lu)的(de)(de)(de)(de)反饋支路(lu)(lu)。恒(heng)(heng)流(liu)(liu)(liu)源(yuan)由VQ820、R822、VD820、C821、R823、T803⑦~⑧和(he)⑦⑨繞組(zu)構(gou)成。其(qi)工作原理是(shi)：在(zai)VQ83截止(zhi)期(qi)間，T803的(de)(de)(de)(de)⑧端(duan)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)正(zheng)，⑨端(duan)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)負。⑨端(duan)的(de)(de)(de)(de)負電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)經R823加(jia)到(dao)(dao)VQ820的(de)(de)(de)(de)基(ji)(ji)(ji)極(ji)，使VQ820截止(zhi)。T803⑧端(duan)的(de)(de)(de)(de)正(zheng)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)通(tong)(tong)(tong)過VD820向C821充(chong)電(dian)(dian)(dian)(dian)，C821上充(chong)得的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)就成為(wei)VQ820導(dao)通(tong)(tong)(tong)時(shi)所需的(de)(de)(de)(de)工作電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)。VQ83導(dao)通(tong)(tong)(tong)時(shi)，T803⑧端(duan)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)變(bian)負，⑨端(duan)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)由負變(bian)正(zheng)。⑧端(duan)的(de)(de)(de)(de)負電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)加(jia)到(dao)(dao)VD820正(zheng)極(ji)使其(qi)截止(zhi)，⑨端(duan)的(de)(de)(de)(de)正(zheng)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)經R823加(jia)到(dao)(dao)VQ820基(ji)(ji)(ji)極(ji)使其(qi)導(dao)通(tong)(tong)(tong)。VQ820導(dao)通(tong)(tong)(tong)后，流(liu)(liu)(liu)經VQ820集-射之間的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)便成為(wei)VQ83的(de)(de)(de)(de)基(ji)(ji)(ji)極(ji)注人(ren)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。VQ820的(de)(de)(de)(de)導(dao)通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)不(bu)受交流(liu)(liu)(liu)輸人(ren)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)波動的(de)(de)(de)(de)影響(xiang)，其(qi)大小取決(jue)于C821上的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)和(he)電(dian)(dian)(dian)(dian)阻R822的(de)(de)(de)(de)大小，所以，VQ83的(de)(de)(de)(de)基(ji)(ji)(ji)極(ji)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)同(tong)樣(yang)不(bu)受交流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)波動的(de)(de)(de)(de)影響(xiang)，這(zhe)就展寬了開(kai)關電(dian)(dian)(dian)(dian)源(yuan)對交流(liu)(liu)(liu)輸入電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)(de)(de)適應范圍。

　　恒流源(yuan)(yuan)(yuan)電(dian)(dian)路6333等。采用STR-S6309組成開關電(dian)(dian)源(yuan)(yuan)(yuan)的彩電(dian)(dian)有：康佳06系列），夏普(pu)25N42-E2、29FN1、29AW1及寬屏W288、W328，熊貓C64P2、2919，長城G8173MF、G8263、G8363，創維CTV-8259、CTV-8298.厚膜電(dian)(dian)路STR-S6308與STR-S6309內(nei)部電(dian)(dian)路結構(gou)基本相同，恒流源(yuan)(yuan)(yuan)電(dian)(dian)路和(he)原理完(wan)全(quan)相同。下(xia)面以STR-S6308厚膜電(dian)(dian)路組成的開關電(dian)(dian)源(yuan)(yuan)(yuan)為例說(shuo)明(ming)其恒流源(yuan)(yuan)(yuan)工作原理。

　　是STR-6308厚膜(mo)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)組成的(de)(de)(de)(de)(de)開(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)源中(zhong)的(de)(de)(de)(de)(de)振(zhen)蕩(dang)和恒(heng)流電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)原理圖。圖中(zhong)，IC801內部(bu)(bu)(bu)的(de)(de)(de)(de)(de)Q1是開(kai)關管(guan)(guan)，R803、R804是振(zhen)蕩(dang)啟(qi)動電(dian)(dian)(dian)(dian)(dian)(dian)阻，C812、R807、T803①-②繞組是振(zhen)蕩(dang)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)(de)(de)反饋(kui)支路(lu)。恒(heng)流源電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)由(you)IC801內部(bu)(bu)(bu)的(de)(de)(de)(de)(de)Q3、R2、R3、D2及(ji)外部(bu)(bu)(bu)的(de)(de)(de)(de)(de)C814、D803、R806和T803①-②繞組構成。其(qi)(qi)恒(heng)流源工(gong)作原理為(wei)(wei)：在(zai)（1截(jie)止(zhi)期間，T803②端電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)為(wei)(wei)正(zheng)，①端電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)為(wei)(wei)負(fu)(fu)(fu)。T803②端電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)通(tong)(tong)(tong)過(guo)IC801內部(bu)(bu)(bu)的(de)(de)(de)(de)(de)D2向C814充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，其(qi)(qi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流路(lu)徑為(wei)(wei)：T803②④一814-803-803①。C814上充(chong)得的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)就(jiu)成為(wei)(wei)Q3導(dao)(dao)通(tong)(tong)(tong)時(shi)所需(xu)要的(de)(de)(de)(de)(de)工(gong)作電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。在(zai)Q1導(dao)(dao)通(tong)(tong)(tong)時(shi)，T803②端電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)由(you)正(zheng)變負(fu)(fu)(fu)，①端電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)由(you)負(fu)(fu)(fu)變正(zheng)。②端的(de)(de)(de)(de)(de)負(fu)(fu)(fu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)加到(dao)D2的(de)(de)(de)(de)(de)正(zheng)極(ji)使其(qi)(qi)截(jie)止(zhi)，①端的(de)(de)(de)(de)(de)正(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)加到(dao)IC801的(de)(de)(de)(de)(de)⑤腳，再通(tong)(tong)(tong)過(guo)其(qi)(qi)內部(bu)(bu)(bu)R3加到(dao)Q3的(de)(de)(de)(de)(de)基(ji)極(ji)使其(qi)(qi)導(dao)(dao)通(tong)(tong)(tong)。Q3導(dao)(dao)通(tong)(tong)(tong)后(hou)，C814通(tong)(tong)(tong)過(guo)Q3放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)，其(qi)(qi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流路(lu)徑為(wei)(wei)：C814正(zheng)極(ji)->IC801dH3ce極(ji)->Qlbe極(ji)―IC801②―R806->C814負(fu)(fu)(fu)極(ji)。Q3導(dao)(dao)通(tong)(tong)(tong)后(hou)，流過(guo)Q3集射之間的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流便(bian)成為(wei)(wei)（1的(de)(de)(de)(de)(de)基(ji)極(ji)注人(ren)電(dian)(dian)(dian)(dian)(dian)(dian)流。因為(wei)(wei)Q3的(de)(de)(de)(de)(de)導(dao)(dao)通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)流不受交(jiao)流輸(shu)人(ren)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)波動的(de)(de)(de)(de)(de)影(ying)響，只取決于C814上的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)(dian)(dian)(dian)阻R806的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)阻大小，所以(yi)，開(kai)關管(guan)(guan)Q1的(de)(de)(de)(de)(de)基(ji)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流同樣不受交(jiao)流電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)波動的(de)(de)(de)(de)(de)影(ying)響，這(zhe)就(jiu)展寬了開(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)海對交(jiao)流輸(shu)人(ren)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)(de)(de)適應(ying)范圍。

　　二、開(kai)關(guan)(guan)(guan)中(zhong)楦流(liu)(liu)源(yuan)(yuan)(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)特(te)點1.含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)的(de)(de)(de)開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)與不(bu)(bu)含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)的(de)(de)(de)開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)區別通過對含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)和不(bu)(bu)含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)對比(bi)，就會發現，這兩(liang)類(lei)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)的(de)(de)(de)振(zhen)蕩(dang)反(fan)(fan)饋(kui)(kui)(kui)(kui)支路(lu)的(de)(de)(de)阻抗(kang)是(shi)不(bu)(bu)同的(de)(de)(de)（反(fan)(fan)饋(kui)(kui)(kui)(kui)支路(lu)主要由電(dian)(dian)(dian)(dian)(dian)(dian)阻和電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)串聯組(zu)成(cheng)）。附表是(shi)這兩(liang)類(lei)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)幾種機(ji)心彩電(dian)(dian)(dian)(dian)(dian)(dian)反(fan)(fan)饋(kui)(kui)(kui)(kui)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)和反(fan)(fan)饋(kui)(kui)(kui)(kui)電(dian)(dian)(dian)(dian)(dian)(dian)阻的(de)(de)(de)統計(ji)表。從統計(ji)表中(zhong)可以看出：含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)的(de)(de)(de)開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)振(zhen)蕩(dang)反(fan)(fan)饋(kui)(kui)(kui)(kui)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)小(xiao)，阻抗(kang)大，反(fan)(fan)饋(kui)(kui)(kui)(kui)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)小(xiao)；不(bu)(bu)含(han)(han)恒(heng)(heng)流(liu)(liu)源(yuan)(yuan)(yuan)的(de)(de)(de)開(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)振(zhen)蕩(dang)反(fan)(fan)饋(kui)(kui)(kui)(kui)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)大，阻抗(kang)小(xiao)，反(fan)(fan)饋(kui)(kui)(kui)(kui)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)大。

　　2.失效后機(ji)器的故障表現開(kai)關(guan)電(dian)(dian)(dian)(dian)源中(zhong)的恒流(liu)電(dian)(dian)(dian)(dian)路失效后，注(zhu)人(ren)開(kai)關(guan)管的基極(ji)電(dian)(dian)(dian)(dian)流(liu)僅有振蕩(dang)反饋支路一路電(dian)(dian)(dian)(dian)流(liu)，只能維持開(kai)關(guan)管處于弱振蕩(dang)狀態(tai)，開(kai)關(guan)電(dian)(dian)(dian)(dian)源的負載能力將會大大降低。遙控(kong)彩(cai)(cai)電(dian)(dian)(dian)(dian)在待(dai)電(dian)(dian)(dian)(dian)子世界(jie)老式(shi)彩(cai)(cai)電(dian)(dian)(dian)(dian)加裝哞技討(tao)嫡(di)t媒葙f鯰(nian)改良(liang)方(fang)鉉李超(chao)2.記錄數(shu)據安裝前測量并記錄彩(cai)(cai)電(dian)(dian)(dian)(dian)各模擬量的電(dian)(dian)(dian)(dian)壓調(diao)(diao)節板±的運放。農彩(cai)(cai)電(dian)(dian)(dian)(dian)中(zhong)模擬量控(kong)制(zhi)電(dian)(dian)(dian)(dian)壓的兩個指(zhi)標(biao)彩(cai)(cai)電(dian)(dian)(dian)(dian)中(zhong)有音量、亮(liang)度等模擬量控(kong)制(zhi)電(dian)(dian)(dian)(dian)路，它們一般用調(diao)(diao)節電(dian)(dian)(dian)(dian)壓的方(fang)式(shi)進行控(kong)制(zhi)。在這種(zhong)電(dian)(dian)(dian)(dian)路中(zhong)，控(kong)制(zhi)電(dian)(dian)(dian)(dian)壓有兩個指(zhi)標(biao)。

　　調節(jie)范圍設電(dian)位器調到上、下(xia)(xia)極限時(shi)(shi)，對應的觸頭電(dian)位分別為Vh、Vl，則控(kong)制電(dian)壓調節(jie)范圍AV=VH―VL.一般來說厶V越(yue)大(da)控(kong)制范圍越(yue)寬。但是，過大(da)的AV會使調節(jie)精度下(xia)(xia)降，影響圖像(xiang)或伴(ban)音質量，嚴重(zhong)時(shi)(shi)彩電(dian)不能正常工(gong)作。

　　平均(jun)電(dian)位平均(jun)電(dian)位丫(ya)=丫(ya)11一￥1/2.丫(ya)的大小(xiao)直(zhi)接影響(xiang)控制(zhi)(zhi)效果。如飽和度控制(zhi)(zhi)中，V過小(xiao)會造成(cheng)圖(tu)像飽和度調不(bu)起(qi)來(lai)，色彩(cai)很淡。所以(yi)在加裝遙控時，AV和V應盡(jin)可能調整到設計水平。如有困難，以(yi)適當(dang)偏高為宜。

　　改(gai)良方(fang)法(fa)的(de)基本構想1.模(mo)擬(ni)量(liang)控(kong)制電(dian)(dian)(dian)(dian)路(lu)的(de)特點老式(shi)彩電(dian)(dian)(dian)(dian)一般有(you)(you)四個(ge)模(mo)擬(ni)量(liang)，如遙控(kong)板上(shang)有(you)(you)四個(ge)相應(ying)(ying)的(de)模(mo)擬(ni)量(liang)輸出電(dian)(dian)(dian)(dian)路(lu)，各由三只電(dian)(dian)(dian)(dian)阻：輸出電(dian)(dian)(dian)(dian)阻，上(shang)、下(xia)偏置電(dian)(dian)(dian)(dian)阻組成(cheng)，在中相應(ying)(ying)的(de)電(dian)(dian)(dian)(dian)阻分別是(shi)R17、R18、R19.其中，輸出電(dian)(dian)(dian)(dian)阻主要(yao)控(kong)制調(diao)節范(fan)圍，上(shang)、下(xia)偏置電(dian)(dian)(dian)(dian)阻主要(yao)控(kong)制平(ping)均電(dian)(dian)(dian)(dian)位。

　　2.現行(xing)的(de)(de)調(diao)(diao)整方法及改(gai)良安裝(zhuang)說明(ming)書(shu)及一般(ban)資料(liao)上介紹的(de)(de)方法是，廢除彩電(dian)(dian)原有的(de)(de)分壓調(diao)(diao)節(jie)電(dian)(dian)路，對(dui)遙控(kong)板上的(de)(de)電(dian)(dian)阻(zu)進行(xing)調(diao)(diao)整。這樣(yang)須調(diao)(diao)整的(de)(de)電(dian)(dian)阻(zu)一般(ban)有12只(zhi)。在(zai)實際工作中要(yao)選定并找到相(xiang)應的(de)(de)電(dian)(dian)阻(zu)并不容易，調(diao)(diao)整起來反反復(fu)復(fu)，耗時多，精度差。

　　從(cong)上面(mian)的分析中，我(wo)們(men)不難發(fa)現：如(ru)果保留彩電(dian)(dian)上的分壓電(dian)(dian)路就可以省掉遙控板(ban)上的分壓電(dian)(dian)路，這(zhe)樣需調(diao)整的電(dian)(dian)阻由(you)12只(zhi)減為(wei)4只(zhi)，大(da)(da)大(da)(da)減少了工作量(liang)，有利于提(ti)高調(diao)整精度。

　　實例-1803PD（S）彩電(dian)(dian)(dian)安(an)裝卓異Z9831遙控器為例，現介紹如下：1.準(zhun)備材料找51kn、200kfl可調電(dian)(dian)(dian)阻(zu)各(ge)一只，按連接，引(yin)線長約30cm.備1/8W電(dian)(dian)(dian)阻(zu)若干。機狀(zhuang)態(tai)，行(xing)、場(chang)(chang)掃描(miao)(miao)電(dian)(dian)(dian)路(lu)停止工(gong)(gong)作(zuo)，開關(guan)(guan)(guan)電(dian)(dian)(dian)源處(chu)于(yu)輕負荷狀(zhuang)態(tai)，即(ji)使恒流(liu)有(you)問題也看不(bu)出它的故障表現。當(dang)電(dian)(dian)(dian)視(shi)(shi)(shi)機處(chu)于(yu)正常收視(shi)(shi)(shi)狀(zhuang)態(tai)，特別是電(dian)(dian)(dian)視(shi)(shi)(shi)屏幕比較(jiao)亮時，行(xing)、場(chang)(chang)掃描(miao)(miao)系統要消(xiao)耗較(jiao)大的功(gong)率(lv)，恒流(liu)源失(shi)效了的開關(guan)(guan)(guan)電(dian)(dian)(dian)源難(nan)以負擔這一重(zhong)任，開關(guan)(guan)(guan)電(dian)(dian)(dian)源將(jiang)會停止工(gong)(gong)作(zuo)。開關(guan)(guan)(guan)電(dian)(dian)(dian)源停止工(gong)(gong)作(zuo)后，行(xing)、場(chang)(chang)掃描(miao)(miao)電(dian)(dian)(dian)路(lu)因失(shi)去供(gong)電(dian)(dian)(dian)也自然(ran)停止工(gong)(gong)作(zuo)，這時開關(guan)(guan)(guan)電(dian)(dian)(dian)源因失(shi)去負載又開始(shi)起振工(gong)(gong)作(zuo)，行(xing)、場(chang)(chang)掃描(miao)(miao)又得到供(gong)電(dian)(dian)(dian)再度工(gong)(gong)作(zuo)，開關(guan)(guan)(guan)管(guan)負擔加重(zhong)又停止工(gong)(gong)作(zuo)，周而復始(shi)，范圍，留作(zuo)調試標(biao)準(zhun)。實測數據為：亮度：7.4彩電(dian)(dian)(dian)電(dian)(dian)(dian)路(lu)改(gai)動關(guan)(guan)(guan)掉彩電(dian)(dian)(dian)電(dian)(dian)(dian)源拔下插頭，將(jiang)各(ge)模擬量的控制(zhi)端(duan)由電(dian)(dian)(dian)位(wei)器的中心抽頭改(gai)接到電(dian)(dian)(dian)位(wei)器的高電(dian)(dian)(dian)位(wei)端(duan)，并與遙控板上(shang)相(xiang)應模擬量的輸出引(yin)線庫接，如所(suo)示。

　　4遙(yao)控板調(diao)整(zheng)拔下(xia)遙(yao)控板上(shang)各(ge)模(mo)擬(ni)量輸出(chu)端的上(shang)下(xia)偏(pian)置電阻共8只，在其它(ta)加裝工作已完成的情況下(xia)，對各(ge)模(mo)擬(ni)量的輸出(chu)電阻進行(xing)調(diao)整(zheng)。以亮(liang)度(du)控制為例(li)，具體步驟如下(xia)：⑴拔下(xia)輸出(chu)電阻R17，將(jiang)51M1可(ke)調(diao)電阻焊上(shang)，通電并用遙(yao)控將(jiang)亮(liang)度(du)調(diao)到最小。如果(guo)熒光屏不亮(liang)，可(ke)用萬用表(biao)監測亮(liang)度(du)控制電壓，下(xia)降到不動為止(zhi)。

　　（2）調(diao)整51kfi可(ke)(ke)調(diao)電(dian)(dian)阻(zu)(zu)使(shi)亮(liang)度(du)(du)控(kong)制電(dian)(dian)壓(ya)為7.4V.關(guan)機(ji)焊下可(ke)(ke)調(diao)電(dian)(dian)阻(zu)(zu)的一端(duan)，測得其阻(zu)(zu)值(zhi)為37kfl.⑶重新焊上可(ke)(ke)調(diao)電(dian)(dian)阻(zu)(zu)并開機(ji)，用遙控(kong)器(qi)將亮(liang)度(du)(du)調(diao)到最大。調(diao)整可(ke)(ke)調(diao)電(dian)(dian)阻(zu)(zu)使(shi)亮(liang)度(du)(du)控(kong)制電(dian)(dian)壓(ya)為7.9V，關(guan)機(ji)焊下可(ke)(ke)調(diao)電(dian)(dian)阻(zu)(zu)，測得其阻(zu)(zu)值(zhi)為40kft.在(zai)步驟⑵、⑶中。如果調(diao)整可(ke)(ke)調(diao)電(dian)(dian)阻(zu)(zu)達不(bu)到所需電(dian)(dian)壓(ya)，就將可(ke)(ke)調(diao)電(dian)(dian)阻(zu)(zu)由51kfl換成(cheng)200M1后重試。

　　⑷一般來說(shuo)，選(xuan)擇偏小的輸出(chu)(chu)電阻使(shi)調節范圍適當擴大為宜(yi)，這里選(xuan)R17=36kft.經測(ce)試(shi)亮(liang)度控(kong)制電壓為7.3~8.IV，效(xiao)果(guo)很理想(xiang)。如(ru)果(guo)選(xuan)R17=33kft，效(xiao)果(guo)也不錯。其(qi)它三個模擬量輸出(chu)(chu)電阻的選(xuan)擇方法與此相同，這里不再(zai)贅(zhui)述。

　　從上(shang)面(mian)的(de)(de)(de)介(jie)紹中(zhong)不(bu)難發現(xian)(xian)這(zhe)種(zhong)方法有(you)三(san)個優點：（1）不(bu)需對(dui)電(dian)(dian)(dian)(dian)路進(jin)行太多分析和了解。⑵需要調(diao)整電(dian)(dian)(dian)(dian)阻(zu)由(you)12只(zhi)(zhi)變成4只(zhi)(zhi)，減(jian)少了工作(zuo)量。⑶調(diao)整精度(du)便于控(kong)(kong)制(zhi)(zhi)，有(you)利(li)于提高(gao)圖像(xiang)(xiang)質量。必須說明的(de)(de)(de)是(shi)，這(zhe)里介(jie)紹的(de)(de)(de)；1一般性的(de)(de)(de)方法，在實(shi)際工作(zuo)中(zhong)應靈(ling)活運用。例如，在對(dui)本例的(de)(de)(de)音(yin)量控(kong)(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)路進(jin)行連接時(shi)，可(ke)將遙控(kong)(kong)板(ban)上(shang)的(de)(de)(de)三(san)只(zhi)(zhi)電(dian)(dian)(dian)(dian)阻(zu)R11、R12、R13拔掉(diao)，將電(dian)(dian)(dian)(dian)視(shi)機(ji)中(zhong)的(de)(de)(de)R302移到(dao)遙控(kong)(kong)板(ban)上(shang)R11的(de)(de)(de)位置，如所示(shi)，則音(yin)量控(kong)(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)壓為0~5.6V，效果(guo)不(bu)錯。對(dui)于控(kong)(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)壓為0~12V的(de)(de)(de)電(dian)(dian)(dian)(dian)路，如夏(xia)普NC-2T的(de)(de)(de)色度(du)和對(dui)比度(du)控(kong)(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)路，可(ke)將遙控(kong)(kong)板(ban)輸(shu)出(chu)端的(de)(de)(de)上(shang)、下(xia)偏(pian)置電(dian)(dian)(dian)(dian)阻(zu)拔掉(diao)，將輸(shu)出(chu)電(dian)(dian)(dian)(dian)阻(zu)換(huan)成l~2kft即可(ke)使用。這(zhe)時(shi)輸(shu)出(chu)電(dian)(dian)(dian)(dian)阻(zu)僅起(qi)限流作(zuo)用，以(yi)(yi)保護遙控(kong)(kong)開(kai)(kai)關電(dian)(dian)(dian)(dian)源只(zhi)(zhi)能(neng)處(chu)于間歇振蕩狀態。表現(xian)(xian)在電(dian)(dian)(dian)(dian)視(shi)屏幕上(shang)的(de)(de)(de)故障現(xian)(xian)象是(shi)：電(dian)(dian)(dian)(dian)視(shi)屏幕亮(liang)(liang)度(du)高(gao)時(shi)，光(guang)柵會(hui)(hui)不(bu)斷地(di)收(shou)(shou)(shou)縮(suo)(suo)。或者(zhe)當(dang)電(dian)(dian)(dian)(dian)視(shi)畫(hua)面(mian)較(jiao)暗(an)(an)時(shi)，圖像(xiang)(xiang)尚能(neng)穩定(ding)住。當(dang)電(dian)(dian)(dian)(dian)視(shi)畫(hua)面(mian)較(jiao)亮(liang)(liang)時(shi)，就會(hui)(hui)出(chu)現(xian)(xian)“光(guang)柵不(bu)停地(di)收(shou)(shou)(shou)縮(suo)(suo)――展(zhan)開(kai)(kai)一收(shou)(shou)(shou)縮(suo)(suo)”。這(zhe)時(shi)你測量+B115V電(dian)(dian)(dian)(dian)壓，在光(guang)柵收(shou)(shou)(shou)縮(suo)(suo)瞬間會(hui)(hui)降至70V左右。該(gai)電(dian)(dian)(dian)(dian)視(shi)機(ji)在調(diao)機(ji)進(jin)行搜(sou)(sou)索時(shi)，搜(sou)(sou)索到(dao)的(de)(de)(de)圖像(xiang)(xiang)比較(jiao)暗(an)(an)時(shi)，可(ke)以(yi)(yi)正常搜(sou)(sou)索并存儲(chu)。搜(sou)(sou)索到(dao)的(de)(de)(de)圖像(xiang)(xiang)較(jiao)亮(liang)(liang)時(shi)，光(guang)柵來回(hui)閃(shan)動，圖像(xiang)(xiang)不(bu)穩定(ding)，或同步不(bu)良，電(dian)(dian)(dian)(dian)視(shi)頻(pin)道不(bu)能(neng)存儲(chu)。

                                                                                                                   本(ben)文摘(zhai)自于(yu)中國鋰電網(wang)