【線(xian)性(xing)(xing)(xing)元件(jian) 非(fei)線(xian)性(xing)(xing)(xing)元件(jian)】線(xian)性(xing)(xing)(xing)元件(jian)和(he)非(fei)線(xian)性(xing)(xing)(xing)元件(jian)的區別(bie) 線(xian)性(xing)(xing)(xing)元件(jian)的特性(xing)(xing)(xing)
線性元件和非線性元件的區別
在金屬導體中電流跟電壓成正比,伏安特性曲線是通過坐標原點的直線,具有這種伏安特性的電學元件叫做線性元件。
對歐姆定律不適(shi)用的導體和器件(jian),即電流(liu)和電壓不成(cheng)正(zheng)比(bi)的電學(xue)元(yuan)件(jian)叫(jiao)做非線(xian)(xian)性元(yuan)件(jian)。非線(xian)(xian)性元(yuan)件(jian)是一種(zhong)通過它的電流(liu)與加(jia)在它兩端電壓不成(cheng)正(zheng)比(bi)的電工(gong)材料,即它的阻值隨(sui)外(wai)界情(qing)況的變(bian)化而改變(bian)。
當(dang)信(xin)(xin)號通(tong)過一個(ge)(ge)元器(qi)(qi)件(jian)后(hou)(hou),信(xin)(xin)號的波形(xing)沒(mei)有改變(bian)(bian),我(wo)們(men)就稱(cheng)之為(wei)(wei)線(xian)性(xing)(xing)器(qi)(qi)件(jian);比(bi)如電(dian)(dian)阻,電(dian)(dian)容。當(dang)信(xin)(xin)號通(tong)過一個(ge)(ge)元器(qi)(qi)件(jian)后(hou)(hou),信(xin)(xin)號的波形(xing)被改變(bian)(bian)了,我(wo)們(men)就稱(cheng)之為(wei)(wei)非(fei)(fei)線(xian)性(xing)(xing)器(qi)(qi)件(jian);比(bi)如二極管,交(jiao)流信(xin)(xin)號通(tong)過它以(yi)后(hou)(hou),只剩下半邊了。線(xian)性(xing)(xing)電(dian)(dian)路(lu)(lu)與非(fei)(fei)線(xian)性(xing)(xing)電(dian)(dian)路(lu)(lu)也是(shi)這樣;當(dang)信(xin)(xin)號通(tong)過一個(ge)(ge)電(dian)(dian)路(lu)(lu)后(hou)(hou),信(xin)(xin)號的波形(xing)沒(mei)有改變(bian)(bian),我(wo)們(men)就稱(cheng)之為(wei)(wei)線(xian)性(xing)(xing)電(dian)(dian)路(lu)(lu);當(dang)信(xin)(xin)號通(tong)過一個(ge)(ge)電(dian)(dian)路(lu)(lu)后(hou)(hou),信(xin)(xin)號的波形(xing)被改變(bian)(bian)了,我(wo)們(men)就稱(cheng)之為(wei)(wei)非(fei)(fei)線(xian)性(xing)(xing)電(dian)(dian)路(lu)(lu)。即(ji)輸入(ru)值(zhi)與輸出值(zhi)的函(han)數曲(qu)線(xian)為(wei)(wei)直(zhi)線(xian),就是(shi)我(wo)們(men)所說的線(xian)性(xing)(xing);否則就是(shi)非(fei)(fei)線(xian)性(xing)(xing)。
線性元件的特性
金屬導體的電流跟電壓成正比,伏安特性曲線是通過坐標原點的直線,電壓與電流的比值叫做電阻,電阻是線性元件。電容和電感雖然不滿足歐姆定律,但其輸入量與輸出量有線性關系:對于電容滿足q=Cu,對于電感則有ψ=Li,這兩條是電容和電感最根本的定義,電容和(he)電(dian)感(gan)也是線性元(yuan)件。
輸(shu)入量和輸(shu)出量沒有線(xian)(xian)性(xing)(xing)關(guan)系的(de)(de)電學(xue)元(yuan)件(jian)叫(jiao)做非線(xian)(xian)性(xing)(xing)元(yuan)件(jian)。典(dian)型的(de)(de)非線(xian)(xian)性(xing)(xing)元(yuan)件(jian)是二極(ji)(ji)管(guan)(guan)、三(san)極(ji)(ji)管(guan)(guan)。求解(jie)含有非線(xian)(xian)性(xing)(xing)元(yuan)件(jian)的(de)(de)電路問題通(tong)常有特殊(shu)方(fang)(fang)(fang)法(fa):在(zai)(zai)定性(xing)(xing)分(fen)析(xi)(xi)(xi)中,重點是掌握理論(lun)上的(de)(de)分(fen)析(xi)(xi)(xi)方(fang)(fang)(fang)法(fa);而在(zai)(zai)定量計(ji)算(suan)中,一般求出的(de)(de)都只能是近似結果。分(fen)析(xi)(xi)(xi)二極(ji)(ji)管(guan)(guan)常用的(de)(de)方(fang)(fang)(fang)法(fa)是分(fen)導通(tong)和關(guan)斷(duan)情況討論(lun),分(fen)析(xi)(xi)(xi)三(san)極(ji)(ji)管(guan)(guan)放大(da)電路也按照三(san)極(ji)(ji)管(guan)(guan)的(de)(de)工作狀(zhuang)態進行(xing)了放大(da)、飽和、截止、倒相四(si)種分(fen)類,這種分(fen)析(xi)(xi)(xi)思路的(de)(de)本(ben)質是分(fen)段線(xian)(xian)性(xing)(xing)化。小(xiao)信號分(fen)析(xi)(xi)(xi)法(fa)也是典(dian)型的(de)(de)非線(xian)(xian)性(xing)(xing)電路分(fen)析(xi)(xi)(xi)方(fang)(fang)(fang)法(fa)之一,其本(ben)質是將非線(xian)(xian)性(xing)(xing)電路在(zai)(zai)小(xiao)信號這種特殊(shu)情況下進行(xing)線(xian)(xian)性(xing)(xing)化等效。
線性元件和非線性元件如何區分
1、電學元件的制成材料并不是“線性元件和非線性元件”的決定因素。例如同樣是金屬材料制成的熱敏電阻、燈泡等都是非線(xian)性元(yuan)件(jian)(jian),而阻(zu)值(zhi)幾乎不(bu)隨工作條(tiao)件(jian)(jian)變化的標準電阻(zu)是線(xian)性元(yuan)件(jian)(jian)。
2、滿足歐姆定(ding)律(lv)的(de)(de)元(yuan)器(qi)(qi)件一定(ding)是(shi)(shi)線性(xing)(xing)元(yuan)件。因為滿足歐姆定(ding)律(lv)的(de)(de)元(yuan)器(qi)(qi)件的(de)(de)伏安特性(xing)(xing)曲線一定(ding)是(shi)(shi)一條過(guo)坐(zuo)標原點(dian)的(de)(de)直(zhi)線。它(ta)的(de)(de)制成材料可(ke)以是(shi)(shi)金屬,也(ye)可(ke)以是(shi)(shi)電解液等(deng)等(deng)。但(dan)反過(guo)來(lai)說,并不是(shi)(shi)所(suo)有的(de)(de)由金屬材料或電解液制成的(de)(de)元(yuan)器(qi)(qi)件都是(shi)(shi)滿足歐姆定(ding)律(lv)的(de)(de)線性(xing)(xing)元(yuan)件。