晶體振蕩器

1.通(tong)常只能(neng)用示波器(晶振(zhen)需加電(dian))或頻率(lv)計測試，萬用表等無法測量， 否則(ze)只能(neng)采用代換法了(le).

2.晶(jing)振常見故(gu)障有:a.內部漏(lou)電(dian)，b.內部開路c.變質頻偏d.外圍相連(lian)電(dian) 容漏(lou)電(dian).這里漏(lou)電(dian)現象，用的(de)VI曲(qu)線應能測出.

3.整(zheng)板測(ce)試(shi)(shi)時可(ke)采用(yong)兩種判斷方法:a.測(ce)試(shi)(shi)時晶振(zhen)附近既周圍的有關 芯片不通過.b.除晶振(zhen)外沒找到(dao)其(qi)它(ta)故障點.

4.晶振常見有(you)2種:a.兩腳(jiao).b.四腳(jiao)，其(qi)中(zhong)第2腳(jiao)是加電源的(de)，注意不可隨(sui) 意短路(lu). 五.故障現象的(de)分布

1.電路板(ban)故障部(bu)位的(de)不完(wan)全統計:1)芯片(pian)損(sun)壞(huai)(huai)30%， 2)分立元件損(sun)壞(huai)(huai)30%， 3)連線(PCB板(ban)敷銅線)斷裂30%， 4)程序破壞(huai)(huai)或丟失10%(有上升趨勢).

2.由上可(ke)(ke)知，當待修電(dian)路板出現聯線(xian)(xian)和程(cheng)序有問題時，又沒(mei)有好板子，既 不熟悉它的連線(xian)(xian)，找不到原程(cheng)序.此板修好的可(ke)(ke)能性就不大了.

網絡排(pai)阻(zu)(zu)，印(yin)(yin)(yin)刷(shua)，差(cha)分(fen)(fen)輸(shu)出(chu)晶振報(bao)價，電(dian)(dian)子尺電(dian)(dian)阻(zu)(zu)板(ban)，差(cha)分(fen)(fen)輸(shu)出(chu)晶振，厚膜電(dian)(dian)容(rong)，噴(pen)碼機(ji)不(bu)銹(xiu)鋼加(jia)(jia)熱(re)片(pian)(pian)(pian)(pian)，濕敏(min)(min)電(dian)(dian)阻(zu)(zu)片(pian)(pian)(pian)(pian)，叉車踏板(ban)傳感(gan)(gan)器電(dian)(dian)阻(zu)(zu)片(pian)(pian)(pian)(pian)，單(dan)列(lie)直插(cha)式(shi)(shi)網絡排(pai)容(rong)，FR4 電(dian)(dian)阻(zu)(zu)板(ban)， 無接觸式(shi)(shi)電(dian)(dian)阻(zu)(zu)傳感(gan)(gan)器，印(yin)(yin)(yin)刷(shua)加(jia)(jia)工(gong)，厚膜芯片(pian)(pian)(pian)(pian).游戲機(ji)控制開(kai)關，差(cha)分(fen)(fen)輸(shu)出(chu)晶振原廠，單(dan)列(lie)直插(cha)式(shi)(shi)網絡排(pai)阻(zu)(zu)，平面印(yin)(yin)(yin)刷(shua)，陶(tao)瓷(ci)(ci)(ci)(ci)印(yin)(yin)(yin)銀，微波爐高壓電(dian)(dian)阻(zu)(zu)，貼片(pian)(pian)(pian)(pian)電(dian)(dian)容(rong)，薄膜電(dian)(dian)阻(zu)(zu)片(pian)(pian)(pian)(pian)，差(cha)分(fen)(fen)輸(shu)出(chu)晶振加(jia)(jia)工(gong)，汽車檔位(wei)陶(tao)瓷(ci)(ci)(ci)(ci)片(pian)(pian)(pian)(pian)，鍵盤印(yin)(yin)(yin)刷(shua)，陶(tao)瓷(ci)(ci)(ci)(ci)鍍金，復印(yin)(yin)(yin)機(ji)陶(tao)瓷(ci)(ci)(ci)(ci)加(jia)(jia)熱(re)片(pian)(pian)(pian)(pian)，貼片(pian)(pian)(pian)(pian)電(dian)(dian)阻(zu)(zu)，薄膜電(dian)(dian)阻(zu)(zu)器，PCB印(yin)(yin)(yin)碳(tan)，打印(yin)(yin)(yin)機(ji)陶(tao)瓷(ci)(ci)(ci)(ci)加(jia)(jia)熱(re)片(pian)(pian)(pian)(pian)，濕度傳感(gan)(gan)器，擾性線路板(ban)，NTC熱(re)敏(min)(min)電(dian)(dian)阻(zu)(zu)，電(dian)(dian)位(wei)計傳感(gan)(gan)器，叉車手搖柄傳感(gan)(gan)器電(dian)(dian)阻(zu)(zu)片(pian)(pian)(pian)(pian)，貼片(pian)(pian)(pian)(pian)電(dian)(dian)感(gan)(gan)

晶體振蕩器實際應用

晶體振(zhen)蕩器實際應用(yong)的(de)(de)(de)(de)環境(jing)需(xu)要慎重考慮。例如，高強度的(de)(de)(de)(de)振(zhen)動(dong)(dong)(dong)或(huo)(huo)沖擊會給振(zhen)蕩器帶來問題。除了可(ke)能產(chan)生物理(li)損壞，振(zhen)動(dong)(dong)(dong)或(huo)(huo)沖擊可(ke)在某些頻率下引起(qi)錯誤的(de)(de)(de)(de)動(dong)(dong)(dong)作。這些外部感(gan)應的(de)(de)(de)(de)擾動(dong)(dong)(dong)會產(chan)生頻率跳動(dong)(dong)(dong)、增加噪聲(sheng)份量以及(ji)間(jian)歇(xie)性(xing)振(zhen)蕩器失效(xiao)。對于要求(qiu)特殊EMI兼容(rong)的(de)(de)(de)(de)應用(yong)，EMI是另一個要優先考慮的(de)(de)(de)(de)問題。除了采用(yong)合適的(de)(de)(de)(de)PC母板布(bu)局技術，重要的(de)(de)(de)(de)是選擇(ze)可(ke)提供輻射量小的(de)(de)(de)(de)時鐘振(zhen)蕩器。一般來說，具有較慢(man)上升/下降時間(jian)的(de)(de)(de)(de)振(zhen)蕩器呈現較好的(de)(de)(de)(de)EMI特性(xing)。我(wo)公司備有大(da)量現貨，有需(xu)要的(de)(de)(de)(de)客戶，歡迎前(qian)來選擇(ze)！

串聯(lian)型(xing)晶體振(zhen)(zhen)蕩器的類型(xing)與電路的振(zhen)(zhen)蕩過程(cheng)

因為(wei)(wei)信號(hao)是反(fan)饋(kui)到VT1發(fa)射(she)(she)極，現假設VT1發(fa)射(she)(she)極電(dian)(dian)(dian)(dian)壓(ya)(ya)瞬時極性(xing)(xing)為(wei)(wei)“+”，集電(dian)(dian)(dian)(dian)極電(dian)(dian)(dian)(dian)壓(ya)(ya)極性(xing)(xing)為(wei)(wei)“+”（發(fa)射(she)(she)極與集電(dian)(dian)(dian)(dian)極是同(tong)相關(guan)系，當(dang)發(fa)射(she)(she)極電(dian)(dian)(dian)(dian)壓(ya)(ya)上(shang)升時集電(dian)(dian)(dian)(dian)極電(dian)(dian)(dian)(dian)壓(ya)(ya)也上(shang)升），VT2的(de)基極電(dian)(dian)(dian)(dian)壓(ya)(ya)極性(xing)(xing)為(wei)(wei)“+”，發(fa)射(she)(she)極電(dian)(dian)(dian)(dian)壓(ya)(ya)極性(xing)(xing)也為(wei)(wei)“+”，該極性(xing)(xing)的(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)通過(guo)X1反(fan)饋(kui)到VT1的(de)發(fa)射(she)(she)極，反(fan)饋(kui)電(dian)(dian)(dian)(dian)壓(ya)(ya)極性(xing)(xing)與假設的(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)極性(xing)(xing)相同(tong)，故該反(fan)饋(kui)為(wei)(wei)正反(fan)饋(kui)。

接通(tong)電(dian)源后，三極(ji)(ji)(ji)管VT1、VT2導通(tong)，VT2發(fa)(fa)(fa)射(she)極(ji)(ji)(ji)輸出(chu)(chu)變化的(de)Ie電(dian)流中包含各種頻(pin)率(lv)的(de)信(xin)(xin)(xin)號(hao)(hao)，石英(ying)晶(jing)體X1對其中的(de)f0信(xin)(xin)(xin)號(hao)(hao)阻抗很(hen)小(xiao)，f0信(xin)(xin)(xin)號(hao)(hao)經(jing)X1、RP1反饋到VT1的(de)發(fa)(fa)(fa)射(she)極(ji)(ji)(ji)，該(gai)信(xin)(xin)(xin)號(hao)(hao)經(jing)VT1放(fang)大(da)后從(cong)集(ji)電(dian)極(ji)(ji)(ji)輸出(chu)(chu)，又加到VT2放(fang)大(da)后從(cong)發(fa)(fa)(fa)射(she)極(ji)(ji)(ji)輸出(chu)(chu)，然后又通(tong)過X1反饋到VT1放(fang)大(da)，如此反復進行，VT2輸出(chu)(chu)的(de)f0信(xin)(xin)(xin)號(hao)(hao)幅(fu)度(du)越來越大(da)，VT1、VT2組成的(de)放(fang)大(da)電(dian)路放(fang)大(da)倍數越來越小(xiao)，當(dang)放(fang)大(da)倍數等于反饋衰減系(xi)數時(shi)，輸出(chu)(chu)f0信(xin)(xin)(xin)號(hao)(hao)幅(fu)度(du)不再變化，電(dian)路輸出(chu)(chu)穩定的(de)f0信(xin)(xin)(xin)號(hao)(hao)。