【線(xian)(xian)(xian)性元件(jian) 非(fei)線(xian)(xian)(xian)性元件(jian)】線(xian)(xian)(xian)性元件(jian)和非(fei)線(xian)(xian)(xian)性元件(jian)的區別 線(xian)(xian)(xian)性元件(jian)的特性
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(lv)不適用(yong)的(de)(de)(de)導體和器件(jian)(jian),即電(dian)(dian)流和電(dian)(dian)壓不成正比(bi)的(de)(de)(de)電(dian)(dian)學元(yuan)件(jian)(jian)叫(jiao)做非(fei)線性元(yuan)件(jian)(jian)。非(fei)線性元(yuan)件(jian)(jian)是(shi)一種通過它的(de)(de)(de)電(dian)(dian)流與加(jia)在它兩端電(dian)(dian)壓不成正比(bi)的(de)(de)(de)電(dian)(dian)工材料,即它的(de)(de)(de)阻(zu)值隨外界情況的(de)(de)(de)變(bian)化而改變(bian)。
當(dang)信號通(tong)過(guo)(guo)一(yi)(yi)個(ge)元(yuan)器(qi)件后,信號的(de)波形(xing)沒有(you)改(gai)變,我(wo)們(men)就(jiu)(jiu)稱(cheng)之(zhi)(zhi)(zhi)為線(xian)(xian)性(xing)器(qi)件;比如(ru)電阻,電容。當(dang)信號通(tong)過(guo)(guo)一(yi)(yi)個(ge)元(yuan)器(qi)件后,信號的(de)波形(xing)被改(gai)變了,我(wo)們(men)就(jiu)(jiu)稱(cheng)之(zhi)(zhi)(zhi)為非(fei)(fei)(fei)線(xian)(xian)性(xing)器(qi)件;比如(ru)二極管(guan),交流信號通(tong)過(guo)(guo)它以(yi)后,只剩(sheng)下半邊了。線(xian)(xian)性(xing)電路與非(fei)(fei)(fei)線(xian)(xian)性(xing)電路也是這(zhe)樣;當(dang)信號通(tong)過(guo)(guo)一(yi)(yi)個(ge)電路后,信號的(de)波形(xing)沒有(you)改(gai)變,我(wo)們(men)就(jiu)(jiu)稱(cheng)之(zhi)(zhi)(zhi)為線(xian)(xian)性(xing)電路;當(dang)信號通(tong)過(guo)(guo)一(yi)(yi)個(ge)電路后,信號的(de)波形(xing)被改(gai)變了,我(wo)們(men)就(jiu)(jiu)稱(cheng)之(zhi)(zhi)(zhi)為非(fei)(fei)(fei)線(xian)(xian)性(xing)電路。即輸入值與輸出值的(de)函數曲線(xian)(xian)為直線(xian)(xian),就(jiu)(jiu)是我(wo)們(men)所說的(de)線(xian)(xian)性(xing);否則就(jiu)(jiu)是非(fei)(fei)(fei)線(xian)(xian)性(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(xian)性元件(jian)。
輸(shu)(shu)入量(liang)和輸(shu)(shu)出(chu)量(liang)沒有(you)線(xian)(xian)(xian)性(xing)(xing)關系(xi)的(de)電學元(yuan)(yuan)件叫做非(fei)線(xian)(xian)(xian)性(xing)(xing)元(yuan)(yuan)件。典型(xing)(xing)的(de)非(fei)線(xian)(xian)(xian)性(xing)(xing)元(yuan)(yuan)件是(shi)二極(ji)(ji)管、三極(ji)(ji)管。求解含有(you)非(fei)線(xian)(xian)(xian)性(xing)(xing)元(yuan)(yuan)件的(de)電路(lu)問題(ti)通常(chang)有(you)特殊(shu)方(fang)(fang)法:在定(ding)性(xing)(xing)分(fen)(fen)析(xi)中,重點(dian)是(shi)掌握理論(lun)上的(de)分(fen)(fen)析(xi)方(fang)(fang)法;而在定(ding)量(liang)計算中,一般(ban)求出(chu)的(de)都只能(neng)是(shi)近(jin)似結果。分(fen)(fen)析(xi)二極(ji)(ji)管常(chang)用的(de)方(fang)(fang)法是(shi)分(fen)(fen)導通和關斷情(qing)況討論(lun),分(fen)(fen)析(xi)三極(ji)(ji)管放大(da)電路(lu)也按照三極(ji)(ji)管的(de)工作狀態進(jin)行了(le)放大(da)、飽和、截止、倒相(xiang)四種(zhong)分(fen)(fen)類,這種(zhong)分(fen)(fen)析(xi)思路(lu)的(de)本(ben)質是(shi)分(fen)(fen)段(duan)線(xian)(xian)(xian)性(xing)(xing)化(hua)。小信(xin)號(hao)分(fen)(fen)析(xi)法也是(shi)典型(xing)(xing)的(de)非(fei)線(xian)(xian)(xian)性(xing)(xing)電路(lu)分(fen)(fen)析(xi)方(fang)(fang)法之一,其本(ben)質是(shi)將非(fei)線(xian)(xian)(xian)性(xing)(xing)電路(lu)在小信(xin)號(hao)這種(zhong)特殊(shu)情(qing)況下進(jin)行線(xian)(xian)(xian)性(xing)(xing)化(hua)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(deng)都是非(fei)線(xian)性(xing)(xing)元(yuan)件(jian),而阻值幾乎不隨工作條件(jian)變化的標準電(dian)阻是線(xian)性(xing)(xing)元(yuan)件(jian)。
2、滿足歐姆(mu)定(ding)律的(de)(de)元(yuan)器件(jian)(jian)一(yi)定(ding)是(shi)線性元(yuan)件(jian)(jian)。因為滿足歐姆(mu)定(ding)律的(de)(de)元(yuan)器件(jian)(jian)的(de)(de)伏(fu)安(an)特(te)性曲線一(yi)定(ding)是(shi)一(yi)條過坐標原點(dian)的(de)(de)直(zhi)線。它的(de)(de)制成(cheng)材料可以是(shi)金屬,也(ye)可以是(shi)電解液等(deng)等(deng)。但反過來說,并(bing)不是(shi)所有的(de)(de)由金屬材料或電解液制成(cheng)的(de)(de)元(yuan)器件(jian)(jian)都是(shi)滿足歐姆(mu)定(ding)律的(de)(de)線性元(yuan)件(jian)(jian)。