檢(jian)(jian)針機(ji)的(de)用(yong)途真是(shi)非常(chang)廣泛(fan)的(de)，對于檢(jian)(jian)針機(ji)廣泛(fan)用(yong)途舉例(li)說明(ming),由(you)于檢(jian)(jian)針機(ji)太過常(chang)見，可能(neng)很多人都沒有注意(yi)到(dao)，檢(jian)(jian)針機(ji)的(de)應用(yong)以及普及到(dao)生活各(ge)個地(di)方。

    目前，檢(jian)針機已經發(fa)揮到了(le)良好的(de)水平，像服(fu)裝、床(chuang)上(shang)用品(pin)、皮鞋毛衫(shan)、食品(pin)和醫(yi)學等方面，檢(jian)針機可以用來檢(jian)測生產(chan)過程中的(de)殘(can)留鐵屑(xie)。

    檢針機是非常可靠的幫手，一方面可以檢測夾雜失落在原料中的斷針，還可以檢測金屬的儀器紫裝，這對于時間的節省和機器的完善有確切性的影響。
　　調(diao)節檢針(zhen)器(qi)高頻振(zhen)(zhen)蕩(dang)器(qi)的增(zeng)益電(dian)位器(qi)，恰好使振(zhen)(zhen)蕩(dang)器(qi)處(chu)于(yu)(yu)臨界振(zhen)(zhen)蕩(dang)狀態，也就是說剛好使振(zhen)(zhen)蕩(dang)器(qi)起振(zhen)(zhen)。當(dang)探測線圈(quan)L1靠近(jin)金屬物(wu)體(ti)時，由于(yu)(yu)電(dian)磁感應現像，會在(zai)金屬導(dao)體(ti)中產生(sheng)渦電(dian)流，使振(zhen)(zhen)蕩(dang)回路中的能量損(sun)耗增(zeng)大(da)，正反饋減弱，處(chu)于(yu)(yu)臨界態的振(zhen)(zhen)蕩(dang)器(qi)振(zhen)(zhen)蕩(dang)減弱，甚至無法維持振(zhen)(zhen)蕩(dang)所(suo)需的最低能量而(er)停振(zhen)(zhen)。如(ru)果能檢測出這種(zhong)變化(hua)，并(bing)轉換成聲音信號，根據(ju)聲音有無，就可以判定(ding)探測線圈(quan)下面(mian)是否有金屬物(wu)體(ti)了。

振蕩(dang)檢測(ce)器

　　振(zhen)(zhen)蕩(dang)檢測器(qi)(qi)由檢針器(qi)(qi)廠家(jia)三極(ji)(ji)(ji)(ji)管(guan)開關(guan)電(dian)(dian)路(lu)和濾(lv)波電(dian)(dian)路(lu)組成(cheng)。開關(guan)電(dian)(dian)路(lu)由三極(ji)(ji)(ji)(ji)管(guan)VT2、二極(ji)(ji)(ji)(ji)管(guan)VD2等組成(cheng)，濾(lv)波電(dian)(dian)路(lu)由濾(lv)波電(dian)(dian)阻器(qi)(qi)R3，濾(lv)波電(dian)(dian)容器(qi)(qi)C2、C3和C4組成(cheng)。在開關(guan)電(dian)(dian)路(lu)中，VT2的基(ji)極(ji)(ji)(ji)(ji)與(yu)(yu)次級線圈L2的“C”端相連，當高(gao)(gao)頻振(zhen)(zhen)蕩(dang)器(qi)(qi)工作(zuo)時，經(jing)高(gao)(gao)頻變(bian)壓器(qi)(qi)T1耦合過來的振(zhen)(zhen)蕩(dang)信(xin)號(hao)，正半(ban)周使VT2導通，VT2集(ji)電(dian)(dian)極(ji)(ji)(ji)(ji)輸出負脈沖信(xin)號(hao)，經(jing)過π型RC濾(lv)波器(qi)(qi)，在負載電(dian)(dian)阻器(qi)(qi)R4上(shang)輸出低電(dian)(dian)平(ping)(ping)信(xin)號(hao)。當高(gao)(gao)頻振(zhen)(zhen)蕩(dang)器(qi)(qi)停振(zhen)(zhen)蕩(dang)時，“C”端無振(zhen)(zhen)蕩(dang)信(xin)號(hao)，又由于二極(ji)(ji)(ji)(ji)管(guan)VD2接在VT2發射極(ji)(ji)(ji)(ji)與(yu)(yu)地之(zhi)間，VT2基(ji)極(ji)(ji)(ji)(ji)被反(fan)向偏置，VT2處于可靠的截止(zhi)狀態，VT2集(ji)電(dian)(dian)極(ji)(ji)(ji)(ji)為高(gao)(gao)電(dian)(dian)平(ping)(ping)，經(jing)過濾(lv)波器(qi)(qi)，在R4上(shang)得(de)到(dao)高(gao)(gao)電(dian)(dian)平(ping)(ping)信(xin)號(hao)。由此可見，當高(gao)(gao)頻振(zhen)(zhen)蕩(dang)器(qi)(qi)正常(chang)工作(zuo)時，在R4上(shang)得(de)到(dao)低電(dian)(dian)平(ping)(ping)信(xin)號(hao)，停振(zhen)(zhen)時，為高(gao)(gao)電(dian)(dian)平(ping)(ping)，由此完成(cheng)了(le)對振(zhen)(zhen)蕩(dang)器(qi)(qi)工作(zuo)狀態的檢測。

音頻振(zhen)蕩器

　　音頻(pin)振(zhen)蕩(dang)器(qi)(qi)(qi)(qi)檢針器(qi)(qi)(qi)(qi)設備(bei)采用(yong)互補(bu)型(xing)多諧振(zhen)蕩(dang)器(qi)(qi)(qi)(qi)，由三(san)(san)極(ji)(ji)(ji)管(guan)VT3、VT4，電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)(qi)(qi)R5、R7、R8和電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)(qi)(qi)(qi)C6組成。互補(bu)型(xing)多諧振(zhen)蕩(dang)器(qi)(qi)(qi)(qi)采用(yong)兩(liang)只不同(tong)類型(xing)的三(san)(san)極(ji)(ji)(ji)管(guan)，其中VT3為(wei)NPN型(xing)三(san)(san)極(ji)(ji)(ji)管(guan)，VT4為(wei)PNP型(xing)三(san)(san)極(ji)(ji)(ji)管(guan)，連接(jie)成互補(bu)的、能(neng)夠(gou)強(qiang)化正反饋的電(dian)(dian)(dian)(dian)(dian)路。在電(dian)(dian)(dian)(dian)(dian)路工作時，它們能(neng)夠(gou)交替地(di)進入導通和截止(zhi)狀態，產(chan)生音頻(pin)振(zhen)蕩(dang)。R7既是(shi)VT3負載電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)(qi)(qi)，又是(shi)VT3導通時VT4基極(ji)(ji)(ji)限流電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)(qi)(qi)。R8是(shi)VT4集電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)負載電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)(qi)(qi)，振(zhen)蕩(dang)脈沖信號由VT4集電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)輸(shu)出(chu)。R5和C6等(deng)是(shi)反饋電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器(qi)(qi)(qi)(qi)和電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)(qi)(qi)(qi)，其數值大(da)小影響振(zhen)蕩(dang)頻(pin)率的高低。