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篇1

【關鍵詞(ci)】數學方(fang)法；高中物理；電磁學

1.引言

國家高(gao)考物(wu)(wu)理(li)科(ke)考試(shi)大綱明(ming)確提出考生應(ying)(ying)具備的(de)(de)(de)第四種能力(li)“應(ying)(ying)用數(shu)學(xue)處理(li)物(wu)(wu)理(li)問題(ti)的(de)(de)(de)能力(li)：能夠(gou)根(gen)據具體問題(ti)列出物(wu)(wu)理(li)量(liang)之間(jian)的(de)(de)(de)關系式(shi)，進行(xing)推(tui)導和求(qiu)解，并根(gen)據結(jie)果得出物(wu)(wu)理(li)結(jie)論，能運用幾(ji)何圖(tu)形(xing)、函數(shu)圖(tu)像進行(xing)表達(da)、分析”，這里所要考查的(de)(de)(de)就(jiu)是(shi)要有靈活運用數(shu)學(xue)方法(fa)處理(li)物(wu)(wu)理(li)問題(ti)的(de)(de)(de)能力(li)。所謂(wei)數(shu)學(xue)方法(fa)，就(jiu)是(shi)在科(ke)學(xue)技術工作(zuo)中，把客觀事物(wu)(wu)的(de)(de)(de)狀態關系和過程(cheng)用數(shu)學(xue)語言(yan)表達(da)出來，進行(xing)推(tui)導、演算和分析，以(yi)形(xing)成對問題(ti)的(de)(de)(de)判斷、解釋和預言(yan)的(de)(de)(de)方法(fa)。下面就(jiu)以(yi)電(dian)磁(ci)學(xue)為例談談幾(ji)種數(shu)學(xue)方法(fa)在高(gao)中物(wu)(wu)理(li)電(dian)磁(ci)學(xue)中的(de)(de)(de)應(ying)(ying)用。

2.函數法

在(zai)(zai)電磁(ci)學(xue)問(wen)題(ti)中(zhong)(zhong)，經常需要(yao)確定兩個物理量間(jian)的(de)變化(hua)所(suo)對應關系（包(bao)括極值(zhi)問(wen)題(ti)），這就需要(yao)利用(yong)函(han)(han)數思想來完成，同時(shi)函(han)(han)數也是進行物理推導判(pan)斷(duan)的(de)重(zhong)要(yao)數學(xue)工具。在(zai)(zai)高(gao)中(zhong)(zhong)物理電磁(ci)學(xue)中(zhong)(zhong)主要(yao)用(yong)到的(de)是一次(ci)函(han)(han)數、一元二次(ci)函(han)(han)數和三角(jiao)函(han)(han)數。

2.1一次函數的(de)應用

在電磁(ci)學問(wen)題中用到的(de)(de)(de)一(yi)次函(han)(han)數(shu)有形如(ru)y=ax或y=ax/（ax+b）a≠0，b≠0形式。一(yi)次函(han)(han)數(shu)y=ax描述的(de)(de)(de)是y與(yu)(yu)x之間呈線性關系，比如(ru)在靜電場中討論F與(yu)(yu)E、U與(yu)(yu)d、Q與(yu)(yu)U等(deng)兩個量間的(de)(de)(de)關系用的(de)(de)(de)就是這(zhe)種函(han)(han)數(shu)。

觀察函數(shu)y=ax/（ax+b（a≠0，b≠0））不難發現(xian)，分子分母(mu)都有未知量(liang)x（自變(bian)量(liang)），如(ru)果(guo)x增加（減(jian)小(xiao)(xiao)），則分子、分母(mu)都同(tong)時增加（減(jian)小(xiao)(xiao)），這樣無法(fa)確定因變(bian)量(liang)y的(de)變(bian)化情況。但是如(ru)果(guo)把分子、分母(mu)都同(tong)時除以x，函數(shu)就變(bian)為y=a/（a+b/x）關系就非常明朗了，y隨(sui)x的(de)增大(da)而(er)增大(da)，y隨(sui)x的(de)減(jian)小(xiao)(xiao)而(er)減(jian)小(xiao)(xiao)。這種一次函數(shu)在(zai)討論閉合電(dian)路(lu)中(zhong)(zhong)路(lu)端電(dian)壓隨(sui)外(wai)電(dian)阻變(bian)化等類似問(wen)題中(zhong)(zhong)經(jing)常有用到。

例1：設(she)一個閉合電(dian)路中(zhong)，電(dian)源電(dian)動勢(shi)為(wei)E，內阻為(wei)r，外(wai)電(dian)路為(wei)純電(dian)阻電(dian)路電(dian)阻為(wei)R，路端電(dian)壓為(wei)U外(wai)，試討論當R發生變化(hua)時，U外(wai)如(ru)何變化(hua)？

分析與解：這類問題既可用閉合電路歐姆定律E=U外(wai)(wai)(wai)(wai)(wai)(wai)(wai)+Ir（間接(jie)(jie)法(fa)(fa)，較易，本文(wen)不做討論）求(qiu)解，也可(ke)用(yong)部(bu)分電路(lu)(lu)歐姆(mu)定(ding)律（直接(jie)(jie)法(fa)(fa)）求(qiu)解。如(ru)果用(yong)直接(jie)(jie)法(fa)(fa)如(ru)何討論呢？根據部(bu)分電路(lu)(lu)歐姆(mu)定(ding)律有U外(wai)(wai)(wai)(wai)(wai)(wai)(wai)=IR①，又由閉合電路(lu)(lu)歐姆(mu)定(ding)律有I=E/（R+r）②，把②代(dai)入(ru)①有U外(wai)(wai)(wai)(wai)(wai)(wai)(wai)=ER/（R+r），這就(jiu)轉化成了形如(ru)一次函數y=ax/（ax+b），故U外(wai)(wai)(wai)(wai)(wai)(wai)(wai)=ER/（r+R）=E/（1+r/R）可(ke)見U外(wai)(wai)(wai)(wai)(wai)(wai)(wai)隨R的增大(da)而增大(da)，隨R的減小而減小。因此當外(wai)(wai)(wai)(wai)(wai)(wai)(wai)電路(lu)(lu)斷開即R∞時，有U外(wai)(wai)(wai)(wai)(wai)(wai)(wai)=E，此為(wei)直接(jie)(jie)測量法(fa)(fa)測電源電動勢的依據；當外(wai)(wai)(wai)(wai)(wai)(wai)(wai)電路(lu)(lu)短路(lu)(lu)時即R0，故。U外(wai)(wai)(wai)(wai)(wai)(wai)(wai)=0。

2.2一(yi)元二次函數的應用(yong)

在處理外電路(lu)為純(chun)電阻(zu)(zu)電路(lu)中電源(yuan)輸出功率隨外電路(lu)電阻(zu)(zu)變化(hua)(hua)規律以(yi)及討論(lun)滑(hua)動變阻(zu)(zu)器(qi)分壓接法電路(lu)中■或■示數變化(hua)(hua)情況(kuang)等類似問題，可以(yi)把電阻(zu)(zu)這(zhe)個動態變化(hua)(hua)物(wu)理量(liang)轉化(hua)(hua)成二次函數y=ax2+bx+c形式，將這(zhe)個函數進行配方整理有(you)：y=a（x+b/2a）2-（4ac-b2）/4a，可見當x=-b/2a時(shi)，y有(you)最值（4ac-b2）/4a。當a>0時(shi)，y有(you)最小(xiao)值，當a

例2：如圖1所示，電源電動勢E=6V，內(nei)阻為r=1？萃，滑動變阻器(qi)R的(de)總阻值為11？萃，固定電阻R0=3？萃，求當(dang)滑動變阻器(qi)從a到b過(guo)程中，■的(de)讀數范圍(wei)。

分(fen)析(xi)與解(jie)：令■讀數I，并設ap部分(fen)電阻(zu)為x，則pb部分(fen)電阻(zu)為11-x，根據閉(bi)合(he)電路(lu)歐(ou)姆定律及并聯(lian)電路(lu)的電流分(fen)配關系：I=6/（R并+11-x+r）×3/（x+3）=18/（-（x-6）2+72）

可(ke)見當x=0時，Imax=0.5A，x=6？萃(cui)時，Imax=0.25A，故■示數范圍為從(cong)0.25A到0.5A連續變化

3.不等式法

不等式可用在半定量討論、推斷及求解極值問題，如在討論(lun)(lun)等量同種電(dian)荷(he)中(zhong)垂(chui)線上場(chang)強大(da)(da)小(xiao)變化(hua)(hua)、某些并聯電(dian)路(lu)中(zhong)■或■示數變化(hua)(hua)以及在兩大(da)(da)小(xiao)材料均相(xiang)同的(de)同種電(dian)荷(he)接(jie)觸后(hou)放回(hui)原處過(guo)程中(zhong)庫侖力大(da)(da)小(xiao)變化(hua)(hua)問題中(zhong)，如果條件(jian)滿足均可以運用重要不等式(shi)a+b≥2■（a、b均為正數）或a+b+c≥33■討論(lun)(lun)最(zui)值(zhi)(zhi)：當和有(you)(you)定(ding)值(zhi)(zhi)，則積有(you)(you)最(zui)大(da)(da)值(zhi)(zhi)；反之(zhi)當積有(you)(you)定(ding)值(zhi)(zhi)，則和有(you)(you)最(zui)小(xiao)值(zhi)(zhi)。

例3.如(ru)圖3所示(shi)，已(yi)知R1=2？萃(cui)，R2=3？萃(cui)，滑(hua)動(dong)變(bian)阻器的最(zui)大值(zhi)R3=5？萃(cui)，則(ze)當滑(hua)動(dong)片(pian)P從a滑(hua)到b過程(cheng)中(zhong)，電流(liu)表示(shi)數的最(zui)小值(zhi)為(wei)多(duo)少(shao)？

分(fen)析(xi)與(yu)解：由閉合電(dian)路歐姆定律可知(zhi)電(dian)流表示數(shu)有(you)最(zui)小(xiao)值時(shi)，外電(dian)路電(dian)阻有(you)最(zui)大(da)值，設ap部分(fen)電(dian)阻為(wei)x，則bp部分(fen)為(wei)5-x，1/R并=1/（2+x）+1/（3+（5-x）），化簡(jian)可得R并=（2+x）（8-x）10，令a=2+x，b=8-x，而a+b=10，故當(dang)(dang)且僅(jin)當(dang)(dang)a=b即(ji)2+x=8-x亦即(ji)x=3？萃(cui)時(shi)ab≤（a+b）/4，故有(you)（2+x）（8-x）≤（102/4）？萃(cui)=25？萃(cui)，所(suo)以■示數(shu)最(zui)小(xiao)值Imin.=2A。

4.幾何法

在(zai)處(chu)理靜電(dian)場中某帶電(dian)體受到庫侖力、重力、拉力等三個(ge)(ge)共點力的動態平衡(heng)(heng)問(wen)題(ti)時，如(ru)果直(zhi)接運用平衡(heng)(heng)條件結(jie)合(he)力的分解(jie)（正交分解(jie)）處(chu)理該類問(wen)題(ti)，過程(cheng)非(fei)常繁瑣，這里可(ke)充分運用帶電(dian)體（質(zhi)點）所(suo)受力的矢量三角(jiao)形與對應(ying)另一個(ge)(ge)由長度組(zu)成的純標(biao)量三角(jiao)形相(xiang)似，這就(jiu)是應(ying)用了平衡(heng)(heng)條件中相(xiang)似三角(jiao)形法，然后(hou)根據題(ti)目條件可(ke)在(zai)短(duan)時間內(nei)快速(su)準確解(jie)決要討論(lun)的問(wen)題(ti)。

例5：一根(gen)絕緣細(xi)線下(xia)拴(shuan)一帶電(dian)(dian)小球A，細(xi)線上的(de)上端固定(ding)在天花板上，在懸點正下(xia)方某(mou)適當位置(zhi)，固定(ding)另一帶同種電(dian)(dian)荷小球B，A靜(jing)止時，懸線與豎直(zhi)方向成θ角，如圖6所示。現緩慢增加B的(de)帶電(dian)(dian)量使θ角逐漸增大，則有(you)關A球所受力的(de)變化，下(xia)列說法正確的(de)是（ ）

A.懸線(xian)的拉力大(da)小不(bu)變(bian) B.懸線(xian)拉力逐漸增大(da)

C.庫(ku)侖力逐漸增大 D.庫(ku)侖力大小可能(neng)不變

分析(xi)與(yu)解：設(she)懸(xuan)線長(chang)為(wei)L，如圖7所示，掛(gua)在細線下(xia)端(duan)的(de)小球(qiu)在重力(li)(li)、細線拉力(li)(li)和電荷之(zhi)間的(de)庫(ku)侖(lun)斥力(li)(li)這(zhe)三個力(li)(li)的(de)作用下(xia)處于平(ping)衡(heng)狀態。由平(ping)衡(heng)條件的(de)相(xiang)似三角形(xing)可知：OAB～ACD，即L/G=L/F=AB/F，可見細線的(de)拉力(li)(li)T=G不變，而(er)庫(ku)侖(lun)力(li)(li)隨著(zhu)AB的(de)增大(da)而(er)增大(da)。故本(ben)題正確答案為(wei)AC。

6.結論

數(shu)學方(fang)法(fa)在(zai)高(gao)中物理電磁(ci)學中應用廣泛而且巧(qiao)妙，本(ben)文主要描述(shu)了(le)函數(shu)法(fa)、不等式法(fa)、圖(tu)象法(fa)及幾何(he)法(fa)，但有時(shi)在(zai)解(jie)決某些復雜(za)電磁(ci)學問題(ti)時(shi)可(ke)能要用到上述(shu)這些方(fang)法(fa)中的(de)兩種或兩種以上，甚至還可(ke)能用到其它方(fang)法(fa)如(ru)極限(xian)法(fa)。因(yin)此，在(zai)解(jie)題(ti)時(shi)可(ke)通過聯想、數(shu)理結合(he)、數(shu)形結合(he)來(lai)靈(ling)活地選擇合(he)適(shi)的(de)數(shu)學方(fang)法(fa)來(lai)解(jie)決電磁(ci)學問題(ti)，這將對提(ti)高(gao)解(jie)決電磁(ci)學問題(ti)的(de)能力大(da)有裨益(yi)。

【參考文獻】

[1]鄭表岳.《中學(xue)物理(li)解題方法》.上(shang)海科技教(jiao)育出版(ban)社，1992年9月

[2]薛金(jin)星.《中學教材全(quan)解(jie)―高(gao)二物(wu)理（上）》.陜西人民教育(yu)出(chu)版(ban)社，2003年5月第(di)4版(ban)

篇2

兩電(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)動勢(shi)分別(bie)為(wei)E1，E2（E1>E2），內阻(zu)分別(bie)為(wei)r1，r2.當這兩個(ge)電(dian)(dian)(dian)(dian)源(yuan)分別(bie)和一(yi)個(ge)阻(zu)值為(wei)R的電(dian)(dian)(dian)(dian)阻(zu)連(lian)接(jie)時，電(dian)(dian)(dian)(dian)源(yuan)輸出功率(lv)相等.若(ruo)將(jiang)R增(zeng)大(da)到(dao)R′，電(dian)(dian)(dian)(dian)源(yuan)輸出功率(lv)為(wei)P1，P2則

A.r1

C.r1>r2，P1r2，P1>P2

分析(xi) 由題目已知條件可得(de)

I0=E1R+r1=E2R+r2 （1）

即(ji)E1E2=R+r1R+r2>1r1>r2， 所以(yi)答案在C，D中選(xuan)擇，當(dang)R增(zeng)大到R′時，

I1=E1R′+r1，I2=E2R′+r2.因此，不能直接判斷出I1與I2的大(da)小關系，所以不好選擇了.

解 比值比較法

令P1=（E1R′+r1）2×R′，P2=（E2R′+r2）2×R′ （2）

則P1P2=（E1E2）2（R′+r2R′+r1）2=（E1E2）2（1+r2-r1R′+r1）2，

令y=1+r2-r1x+r1，當x=R時，y=1；r2-r1

此函數(shu)為增函數(shu)（由(you)y=kx，k>0減(jian)函數(shu)，k

所以，當R′>R時(shi)，P1P2>1，即P1>P2，答案選擇(ze)D， 同理可以推出R′

點評 此(ci)方(fang)法(fa)(fa)是根據題目(mu)中(zhong)(zhong)的(de)(de)問題是比(bi)(bi)較(jiao)功率大小，所以回(hui)憶起數學(xue)中(zhong)(zhong)常用(yong)的(de)(de)比(bi)(bi)較(jiao)方(fang)法(fa)(fa)有比(bi)(bi)值比(bi)(bi)較(jiao)法(fa)(fa)，此(ci)方(fang)法(fa)(fa)利用(yong)了數學(xue)中(zhong)(zhong)函(han)數的(de)(de)函(han)數知識（增函(han)數與減函(han)數），根據初始時(shi)P1=P2時(shi)的(de)(de)結論進行演算推理，其(qi)中(zhong)(zhong)判(pan)斷函(han)數的(de)(de)增減性(xing)是關鍵(jian)性(xing)步(bu)驟.

解2 差值比較法

P1-P2=（E1R′+r1）2×R′-（E2R′+r2）2×R′ （4）

由（1）、（2）、（4）式(shi)可得

P1-P2=E21R′（RR′+r1R′+r2R+r1r2）2-E21R′（RR′+r2R′+r1R+r1r2）2[（R′+r1）（R′+r2）（R+r1）]

（5）

r1>r2，R′>R

由（r1-r2）R′>（r1-r2）R，

即(ji)RR′+r1R′+r2R+r1r2>RR′+r2R′+r1R+r1r2 （6）

由（5）、（6）式可得(de)P1-P2>0P1>P2， 結論同(tong)上.

點評 此方(fang)法也是比(bi)(bi)較法中(zhong)常用的差值比(bi)(bi)較法，此方(fang)法中(zhong)進(jin)行(xing)的推理計算(suan)(suan)過程(cheng)比(bi)(bi)較復雜，然后根據已知條(tiao)件聯系(xi)到比(bi)(bi)較的表(biao)達式進(jin)行(xing)變(bian)化是此方(fang)法的難點，此方(fang)法思路簡單(dan)清晰(xi)計算(suan)(suan)復雜.

解3 導數的幾何(he)意義法

函(han)(han)(han)數(shu)(shu)(shu)的(de)一階導(dao)(dao)數(shu)(shu)(shu)表(biao)示函(han)(han)(han)數(shu)(shu)(shu)在(zai)這點(dian)切線的(de)斜率，因此(ci)如(ru)果函(han)(han)(han)數(shu)(shu)(shu)f（x）的(de)一階導(dao)(dao)數(shu)(shu)(shu)大于(yu)零(ling)，則f（x）為(wei)增函(han)(han)(han)數(shu)(shu)(shu)，如(ru)果函(han)(han)(han)數(shu)(shu)(shu)f（x）的(de)一階導(dao)(dao)數(shu)(shu)(shu)小(xiao)于(yu)零(ling)，則f（x）為(wei)減函(han)(han)(han)數(shu)(shu)(shu)，如(ru)果函(han)(han)(han)數(shu)(shu)(shu)f（x）的(de)一階導(dao)(dao)數(shu)(shu)(shu)等于(yu)零(ling)，則f（x）有極值.

令(ling)R=x，由(you)（1）、（2）式子得

f（x）=p1P2=（E1E2）2（x+r2x+r1）2 （7）

對（7）式自變量x求一階導數得

f ′（x）=p1P2=（E1E2）2（r1-r2）（x=r1）2 （8）

因(yin)為r1-r2>0，所以f ′（x）>0，函數為增函數.

當x=R時(shi)（7）式等于1，所以x=R′>R時(shi)（7）式p1P2>1P1>P2，結論同上.

點評 利用(yong)此(ci)方法(fa)需(xu)要(yao)兩個數(shu)(shu)(shu)(shu)學(xue)(xue)基礎(chu)，一是(shi)要(yao)知道函(han)數(shu)(shu)(shu)(shu)某一點導(dao)數(shu)(shu)(shu)(shu)的(de)幾何意義即表示某一點切線的(de)斜(xie)率；二是(shi)要(yao)熟(shu)練掌握求(qiu)導(dao)函(han)數(shu)(shu)(shu)(shu)的(de)相應數(shu)(shu)(shu)(shu)學(xue)(xue)公式和求(qiu)導(dao)法(fa)則.此(ci)方法(fa)比(bi)較巧妙的(de)將數(shu)(shu)(shu)(shu)學(xue)(xue)的(de)導(dao)數(shu)(shu)(shu)(shu)與增(zeng)減函(han)數(shu)(shu)(shu)(shu)應用(yong)到解決(jue)物理(li)實(shi)際問(wen)題當中，是(shi)應用(yong)數(shu)(shu)(shu)(shu)學(xue)(xue)知識(shi)解決(jue)物理(li)問(wen)題的(de)典范.

解4 畫曲為直法

由閉合(he)電路(lu)歐姆定律I=ER+r可知I與R非線性變(bian)化，兩側同(tong)時取(qu)倒數有

1I=RE+rE （9）

由（9）式可得當R′=R+ΔR（ΔR>0）時，對兩個(ge)電源分(fen)別應用（9）式有

1I1=R+ΔRE1+r1E1=ΔRE1+R+r1E1

1I2=R+ΔRE2+r2E2=ΔRE2+R+r1E2 （10）

由（1）、（10）和E1>E2可以推出I1>I2， 此(ci)時P1=I21× R′>P2=I22×R′.

即(ji)P1>P2，結論同上.

點評 此方(fang)法(fa)(fa)十分巧妙的利(li)用(yong)了題(ti)目中的初始條件，將(jiang)本來(lai)無法(fa)(fa)直接判斷的曲線(xian)問題(ti)轉(zhuan)化為直線(xian)問題(ti)來(lai)解決，畫曲線(xian)為直線(xian)的方(fang)法(fa)(fa)是(shi)(shi)解決物理(li)問題(ti)中經常使用(yong)的方(fang)法(fa)(fa).特(te)別是(shi)(shi)設后來(lai)的電阻R′+R+ΔR（Δ>0） 將(jiang)本來(lai)無法(fa)(fa)比較的問題(ti)變得十分容易比較.

解5 U-I圖象法

根據閉(bi)合電路歐姆定律E=U+Ir變形可以得(de)

U=-rI+E （15）

將(jiang)U看(kan)成I的(de)函數(shu)可(ke)知(zhi)是線(xian)性變化(hua)關(guan)(guan)系(xi)(xi)(xi)，圖(tu)(tu)象(xiang)的(de)斜率(lv)的(de)絕(jue)對(dui)值代表內(nei)阻(zu)(zu)(zu)，圖(tu)(tu)象(xiang)的(de)截距(ju)代表電(dian)源電(dian)動(dong)勢.而外(wai)電(dian)阻(zu)(zu)(zu)滿足(zu)U=IR在同一(yi)個(ge)坐(zuo)標系(xi)(xi)(xi)中將(jiang)兩(liang)個(ge)函數(shu)同時畫出(chu)來，由（15）式可(ke)知(zhi)得U=-r1I+E1，U=-r2I+E2，U=IR，滿足(zu)P1=P2初始條件點(dian)就是兩(liang)個(ge)函數(shu)的(de)交點(dian)狀(zhuang)(zhuang)態，外(wai)電(dian)阻(zu)(zu)(zu)的(de)大(da)小由U=RI直線(xian)的(de)斜率(lv)來表示，根據題(ti)意后(hou)來電(dian)阻(zu)(zu)(zu)R′>R與兩(liang)個(ge)電(dian)源的(de)交點(dian)就分別代表了(le)此(ci)時的(de)狀(zhuang)(zhuang)態，由圖(tu)(tu)1直接可(ke)以(yi)看(kan)出(chu)后(hou)來電(dian)流關(guan)(guan)系(xi)(xi)(xi)為I1>I2，路端電(dian)壓關(guan)(guan)系(xi)(xi)(xi)為U1>U2，則關(guan)(guan)系(xi)(xi)(xi)P1=U1I1>P2=U2I2，即當R′>R時，有P1>P2，結論同上.

點評 此方法是(shi)(shi)將教材(cai)中(zhong)熟悉的(de)知識（測電(dian)(dian)源電(dian)(dian)動(dong)勢與內(nei)阻(zu)試驗數據(ju)處(chu)理(li)知識）遷移到具體(ti)的(de)情景之中(zhong)，用此方法需要(yao)對(dui)(dui)U=-rI+E對(dui)(dui)應的(de)U-I圖(tu)象(xiang)的(de)物(wu)理(li)意義掌握的(de)十分清楚，對(dui)(dui)于(yu)圖(tu)象(xiang)中(zhong)的(de)外電(dian)(dian)阻(zu)U=RI 在同(tong)一圖(tu)象(xiang)中(zhong)構建出來是(shi)(shi)解決問(wen)題(ti)的(de)關鍵(jian)步驟.同(tong)時對(dui)(dui)于(yu)圖(tu)象(xiang)中(zhong)的(de)電(dian)(dian)源內(nei)阻(zu)是(shi)(shi)斜率(lv)的(de)絕(jue)對(dui)(dui)值要(yao)掌握，外電(dian)(dian)阻(zu)消耗的(de)功率(lv)就(jiu)是(shi)(shi)矩(ju)形的(de)面積.

解6 功率圖象法

由P=（ER+r）2R=E2R+r2/R+2r

（11）

是高中常見的電源輸出功率公式對應(ying)函數關系(xi)為

f（x）=E2x+r2/x+2r

當x=r時，電源輸出(chu)電功率(lv)最大為(wei)P=E2/4r，對(dui)應的函數圖象為(wei)圖2所(suo)示.要滿(man)足初(chu)始條(tiao)件功率(lv)相等(deng)也就是函數

P1=E21R+r21/R+2r1P2=E22R+r22/R+2r2 （12）

對(dui)應兩個函數有(you)交點(dian)，同時由于r1>r2所限(xian)制，所以兩條曲線相(xiang)交的交點(dian)只能(neng)存在三種(zhong)可(ke)能(neng)就是如(ru)圖3所示A，B，C三個點(dian)，無論(lun)哪種(zhong)情(qing)況，在取(qu)R'>R時總有(you)P1>P2結論(lun)同上(shang).

點評 此(ci)方法是(shi)從我們熟(shu)悉(xi)的(de)電(dian)(dian)源(yuan)(yuan)輸(shu)出(chu)功率(lv)問題進行討論，要知道電(dian)(dian)源(yuan)(yuan)輸(shu)出(chu)功率(lv)最大(da)時(shi)(shi)，就(jiu)是(shi)當(dang)外(wai)電(dian)(dian)阻(zu)(zu)（外(wai)電(dian)(dian)路是(shi)純(chun)電(dian)(dian)阻(zu)(zu)）等(deng)于(yu)電(dian)(dian)源(yuan)(yuan)內阻(zu)(zu)時(shi)(shi)，同(tong)時(shi)(shi)要知道函數圖象的(de)變化(hua)趨(qu)勢(shi)，從極限(xian)分析可以知當(dang)R=0時(shi)(shi)，電(dian)(dian)源(yuan)(yuan)電(dian)(dian)路輸(shu)出(chu)功率(lv)等(deng)于(yu)零(ling)(ling)（相當(dang)于(yu)短(duan)路），R=+∞時(shi)(shi)，輸(shu)出(chu)功率(lv)也是(shi)零(ling)(ling)（相當(dang)于(yu)斷路），當(dang)外(wai)電(dian)(dian)阻(zu)(zu)等(deng)于(yu)電(dian)(dian)源(yuan)(yuan)內阻(zu)(zu)時(shi)(shi)，有最大(da)值.這樣變化(hua)趨(qu)勢(shi)圖自然就(jiu)畫出(chu)來(lai)了(le)，同(tong)時(shi)(shi)兩曲(qu)線有一(yi)個交(jiao)點（R>0時(shi)(shi)），結(jie)論就(jiu)一(yi)目了(le)然了(le).

解7 電流圖象法

由（1）式(shi)可(ke)得(de)當功率相等時外電阻的阻值為

R=E2r1-E1r2E1-E2 （13）

令E1=4V，E2=3V，r1=2Ω，r2=1Ω，

代入（13）式(shi)可(ke)以得到 R=2Ω

由(you)閉合(he)電路歐姆定(ding)律 I=ER+r （14）

可知(zhi)I與R非(fei)線性(xing)關系(xi)，代入以(yi)上數據(ju)可以(yi)得到 i1=E1R+r1=1A

同理 I2=E2R+r2=1 A

當(dang)R=1Ω和R=3Ω分別代(dai)入（14）式計算得到對應的電流值分別為I1′=0.8A，I1″=1.33A，

I2′=0.75A， I2″=1.5A.

篇3

關鍵詞：初中生；高中生；物(wu)理知識銜(xian)接

作(zuo)者簡介：邊桂萍（1974-），女，吉(ji)林省(sheng)柳河縣人(ren)，大學(xue)(xue)(xue)(xue)(xue)本科，中(zhong)(zhong)學(xue)(xue)(xue)(xue)(xue)高(gao)級(ji)教(jiao)(jiao)師(shi).吉(ji)林省(sheng)骨干教(jiao)(jiao)師(shi)，吉(ji)林省(sheng)第十二批有突出貢獻的(de)(de)(de)中(zhong)(zhong)青年(nian)專業技術人(ren)才，吉(ji)林省(sheng)教(jiao)(jiao)書育人(ren)楷模，吉(ji)林省(sheng)第五批創新拔(ba)尖人(ren)才.大多數初中(zhong)(zhong)學(xue)(xue)(xue)(xue)(xue)生(sheng)剛升入高(gao)中(zhong)(zhong)時普遍反映物(wu)理(li)學(xue)(xue)(xue)(xue)(xue)科存在(zai)(zai)著銜接(jie)不暢的(de)(de)(de)問(wen)題，在(zai)(zai)高(gao)中(zhong)(zhong)的(de)(de)(de)學(xue)(xue)(xue)(xue)(xue)習(xi)過程(cheng)中(zhong)(zhong)，對(dui)物(wu)理(li)的(de)(de)(de)具體學(xue)(xue)(xue)(xue)(xue)習(xi)方(fang)(fang)法和內容模糊不清，一臉茫然不知所措.筆者在(zai)(zai)近幾(ji)年(nian)的(de)(de)(de)學(xue)(xue)(xue)(xue)(xue)習(xi)和探索過程(cheng)中(zhong)(zhong)，覺得在(zai)(zai)以下幾(ji)個(ge)方(fang)(fang)面(mian)需要(yao)同行(xing)們在(zai)(zai)教(jiao)(jiao)學(xue)(xue)(xue)(xue)(xue)過程(cheng)別(bie)注意.

一、初(chu)中(zhong)和高中(zhong)的不同

1.教材方面

（1）初中教材：a要(yao)求學生(sheng)了解、知道的(de)內容多，要(yao)求學生(sheng)掌握(wo)的(de)少；b定性的(de)多，定量的(de)少；c教材難度低，趣味濃(nong)，一般由實驗或(huo)生(sheng)活實際引入課題，通過現(xian)象總結規律，形象具體，易(yi)于接受.

（2）高中教材：a重視(shi)理論(lun)上的分析指(zhi)導；b定量(liang)(liang)研究多(duo)，計算(suan)量(liang)(liang)加大；c數(shu)學工具(ju)的應用(yong)明顯加強與提高，不僅運算(suan)量(liang)(liang)加大，且(qie)常要運用(yong)函數(shu)、圖象(xiang)和極(ji)值等數(shu)學方法來研究物理現象(xiang)和過程.

2.教法與(yu)學法方(fang)面

（1）初(chu)中(zhong)狀態主要(yao)表現在以下(xia)幾個方(fang)面：a教(jiao)學(xue)內容(rong)要(yao)求相對低，教(jiao)師課堂更注重(zhong)教(jiao)學(xue)的(de)(de)趣味性，課堂容(rong)量少，進度慢；b對重(zhong)點概念及規律反復討論達成學(xue)生對重(zhong)點知識的(de)(de)掌握；c習題(ti)類型(xing)少，變化也不多(duo)，且多(duo)數與教(jiao)師課上講的(de)(de)內容(rong)、例題(ti)對得上，造成考試時往往只要(yao)記住分式(shi)，做好筆記，就有可(ke)能取得很好的(de)(de)成績(ji).

（2）高(gao)(gao)中(zhong)狀(zhuang)態(tai)則主(zhu)要(yao)表現在以(yi)下幾個方(fang)面：a教學(xue)進(jin)度明顯加快，課(ke)堂(tang)容量(liang)大；b知(zhi)識要(yao)求(qiu)大大提(ti)高(gao)(gao)，需要(yao)學(xue)生自(zi)己多(duo)分析、思考(kao)、練(lian)習才能真正掌(zhang)握，習題類型更是復雜多(duo)變，單(dan)靠對概念、規律和(he)公式(shi)的(de)死記(ji)硬(ying)背(bei)，解決(jue)不了(le)問題.

二、剛步入高中后學生(sheng)的困惑與問(wen)題

1.教(jiao)(jiao)材方(fang)面：a大量的(de)數(shu)(shu)學(xue)(xue)與(yu)物(wu)理(li)(li)(li)結合，大量的(de)物(wu)理(li)(li)(li)過程推導(dao)，學(xue)(xue)生感到(dao)物(wu)理(li)(li)(li)抽象難學(xue)(xue)，甚(shen)至望(wang)而(er)生畏；b學(xue)(xue)生知識儲備不夠.數(shu)(shu)學(xue)(xue)教(jiao)(jiao)學(xue)(xue)進度跟不上物(wu)理(li)(li)(li)教(jiao)(jiao)學(xue)(xue)需要(yao)，學(xue)(xue)科間的(de)不銜(xian)接給學(xue)(xue)生數(shu)(shu)學(xue)(xue)工(gong)具(ju)的(de)運用帶來了困難，加(jia)大了物(wu)理(li)(li)(li)學(xue)(xue)習(xi)的(de)難度.

2.教法(fa)與學(xue)法(fa)方面：a很多學(xue)生養成了死(si)記硬(ying)背(bei)的(de)壞習(xi)慣；b很多學(xue)生養成只想硬(ying)套公式，而沒(mei)有主動分(fen)析(xi)、思考問題的(de)能(neng)力；c很多初中學(xue)生的(de)學(xue)法(fa)是(shi)：跟(gen)著教師(shi)轉，死(si)記硬(ying)背(bei)教師(shi)布置的(de)內容.

三、對初中和高中教學的(de)改(gai)進(jin)建議

1.教材方面：

a強化初中(zhong)學生運算能(neng)力的提升，特別是解方程組能(neng)力的要(yao)求(qiu)；

b弱(ruo)化(hua)初中學生對計(ji)算器的依賴；

c要(yao)求(qiu)學生(sheng)提升初(chu)中簡單(dan)三角(jiao)函(han)數(shu)的運(yun)用能力，熟(shu)練掌握正弦(xian)(xian)、余弦(xian)(xian)、正切的計算及(ji)一些特(te)殊(shu)角(jiao)的三角(jiao)函(han)數(shu)值(zhi)，要(yao)求(qiu)學生(sheng)熟(shu)練掌握二次函(han)數(shu)極值(zhi)運(yun)算與一次函(han)數(shu)，反比(bi)例函(han)數(shu)、正比(bi)例函(han)數(shu)的平移、截距、斜(xie)率、圖形(xing)所圍面積(ji)等知識.

2.教(jiao)法與學法方面：

a中考命題要與高考命題的導(dao)向接軌；

b初(chu)中教學(xue)，必須改(gai)變死記硬(ying)背的習(xi)(xi)慣(guan)，要(yao)注重培養學(xue)生主動分析(xi)問題(ti)、解決(jue)問題(ti)的習(xi)(xi)慣(guan)；

c加強培養學(xue)生(sheng)課前自主學(xue)習能(neng)力；

篇4

在中職(zhi)電(dian)(dian)(dian)(dian)子類(lei)專(zhuan)業教(jiao)學(xue)(xue)(xue)內(nei)(nei)(nei)容(rong)中，數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)應(ying)(ying)用(yong)(yong)的(de)(de)(de)(de)(de)(de)范圍(wei)很廣，幾乎涉及(ji)傳(chuan)(chuan)統中等數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)的(de)(de)(de)(de)(de)(de)所有分(fen)支(zhi)。梳理這些內(nei)(nei)(nei)容(rong)、探(tan)討相應(ying)(ying)的(de)(de)(de)(de)(de)(de)教(jiao)學(xue)(xue)(xue)策(ce)略，對于(yu)提高(gao)(gao)電(dian)(dian)(dian)(dian)子專(zhuan)業的(de)(de)(de)(de)(de)(de)教(jiao)學(xue)(xue)(xue)質(zhi)量(liang)有著重(zhong)要(yao)的(de)(de)(de)(de)(de)(de)意義。中職(zhi)專(zhuan)業課(ke)(ke)數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)應(ying)(ying)用(yong)(yong)教(jiao)學(xue)(xue)(xue)質(zhi)量(liang)在中職(zhi)電(dian)(dian)(dian)(dian)子類(lei)專(zhuan)業教(jiao)學(xue)(xue)(xue)內(nei)(nei)(nei)容(rong)中，數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)應(ying)(ying)用(yong)(yong)的(de)(de)(de)(de)(de)(de)范圍(wei)很廣，幾乎涉及(ji)傳(chuan)(chuan)統中等數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)的(de)(de)(de)(de)(de)(de)所有分(fen)支(zhi)。此(ci)外，涉及(ji)現(xian)代(dai)數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)基(ji)(ji)礎(chu)(chu)部(bu)分(fen)的(de)(de)(de)(de)(de)(de)一(yi)些內(nei)(nei)(nei)容(rong)。梳理這些內(nei)(nei)(nei)容(rong)、探(tan)討相應(ying)(ying)的(de)(de)(de)(de)(de)(de)教(jiao)學(xue)(xue)(xue)策(ce)略，對于(yu)提高(gao)(gao)電(dian)(dian)(dian)(dian)子專(zhuan)業的(de)(de)(de)(de)(de)(de)教(jiao)學(xue)(xue)(xue)質(zhi)量(liang)有著重(zhong)要(yao)的(de)(de)(de)(de)(de)(de)意義。一(yi)、梳理好傳(chuan)(chuan)統中等數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)內(nei)(nei)(nei)容(rong)在電(dian)(dian)(dian)(dian)子類(lei)課(ke)(ke)程(cheng)中的(de)(de)(de)(de)(de)(de)應(ying)(ying)用(yong)(yong)，構(gou)(gou)建基(ji)(ji)本(ben)(ben)數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)應(ying)(ying)用(yong)(yong)意識與(yu)能力1.集(ji)(ji)合(he)論(lun)與(yu)邏輯(ji)運(yun)(yun)算在數(shu)(shu)(shu)(shu)字電(dian)(dian)(dian)(dian)路中運(yun)(yun)用(yong)(yong)“集(ji)(ji)合(he)”的(de)(de)(de)(de)(de)(de)概念及(ji)公理化的(de)(de)(de)(de)(de)(de)現(xian)代(dai)集(ji)(ji)合(he)理論(lun)體系構(gou)(gou)成現(xian)代(dai)數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)的(de)(de)(de)(de)(de)(de)支(zhi)柱。在中職(zhi)電(dian)(dian)(dian)(dian)子類(lei)專(zhuan)業教(jiao)學(xue)(xue)(xue)內(nei)(nei)(nei)容(rong)中中，經典集(ji)(ji)合(he)論(lun)的(de)(de)(de)(de)(de)(de)運(yun)(yun)用(yong)(yong)主要(yao)體現(xian)在數(shu)(shu)(shu)(shu)字電(dian)(dian)(dian)(dian)路的(de)(de)(de)(de)(de)(de)邏輯(ji)運(yun)(yun)算特(te)征上(shang)：“和(he)”運(yun)(yun)算對應(ying)(ying)于(yu)集(ji)(ji)合(he)的(de)(de)(de)(de)(de)(de)“并”，“且”運(yun)(yun)算對應(ying)(ying)于(yu)集(ji)(ji)合(he)的(de)(de)(de)(de)(de)(de)“交(jiao)”，而(er)電(dian)(dian)(dian)(dian)位高(gao)(gao)低則對應(ying)(ying)于(yu)二進(jin)制下的(de)(de)(de)(de)(de)(de)“0”“1”，電(dian)(dian)(dian)(dian)路的(de)(de)(de)(de)(de)(de)不同(tong)狀態(tai)對應(ying)(ying)于(yu)一(yi)系列“0”“1”的(de)(de)(de)(de)(de)(de)不同(tong)排列組合(he)，進(jin)而(er)完成許多運(yun)(yun)算功(gong)能。但，它(ta)們的(de)(de)(de)(de)(de)(de)數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)基(ji)(ji)礎(chu)(chu)是(shi)集(ji)(ji)合(he)的(de)(de)(de)(de)(de)(de)幾種基(ji)(ji)本(ben)(ben)運(yun)(yun)算：集(ji)(ji)合(he)的(de)(de)(de)(de)(de)(de)包含、交(jiao)、并、補關(guan)系，特(te)別是(shi)在此(ci)基(ji)(ji)礎(chu)(chu)上(shang)拓展出的(de)(de)(de)(de)(de)(de)摩(mo)根(gen)律，這是(shi)中職(zhi)數(shu)(shu)(shu)(shu)學(xue)(xue)(xue)教(jiao)學(xue)(xue)(xue)必須重(zhong)視(shi)的(de)(de)(de)(de)(de)(de)基(ji)(ji)本(ben)(ben)計算規律。2.函(han)數(shu)(shu)(shu)(shu)的(de)(de)(de)(de)(de)(de)基(ji)(ji)本(ben)(ben)性(xing)質(zhi)的(de)(de)(de)(de)(de)(de)應(ying)(ying)用(yong)(yong)與(yu)電(dian)(dian)(dian)(dian)子類(lei)課(ke)(ke)程(cheng)教(jiao)學(xue)(xue)(xue)緊密結合(he)函(han)數(shu)(shu)(shu)(shu)（尤(you)其(qi)是(shi)幾類(lei)常見初等函(han)數(shu)(shu)(shu)(shu)：冪函(han)數(shu)(shu)(shu)(shu)、指數(shu)(shu)(shu)(shu)函(han)數(shu)(shu)(shu)(shu)、對數(shu)(shu)(shu)(shu)函(han)數(shu)(shu)(shu)(shu)、三角函(han)數(shu)(shu)(shu)(shu)、反三角函(han)數(shu)(shu)(shu)(shu)、多項式函(han)數(shu)(shu)(shu)(shu)與(yu)分(fen)式線性(xing)函(han)數(shu)(shu)(shu)(shu)）的(de)(de)(de)(de)(de)(de)基(ji)(ji)本(ben)(ben)性(xing)質(zhi)，其(qi)范疇至少包括函(han)數(shu)(shu)(shu)(shu)的(de)(de)(de)(de)(de)(de)定義、定義域、值(zhi)域、增減性(xing)（單調性(xing)）、極值(zhi)與(yu)拐點(dian)。

例如(ru)(ru)，如(ru)(ru)圖所示的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong)(zhong)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)E的(de)(de)(de)(de)(de)(de)(de)(de)內(nei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻為(wei)(wei)r，問(wen)(wen)(wen)(wen)：揚聲器R的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻多大(da)時，揚聲器獲得的(de)(de)(de)(de)(de)(de)(de)(de)功(gong)率較大(da)？電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong)(zhong)把這(zhe)(zhe)類(lei)問(wen)(wen)(wen)(wen)題(ti)稱(cheng)為(wei)(wei)“功(gong)率匹配問(wen)(wen)(wen)(wen)題(ti)”這(zhe)(zhe)兒(er)的(de)(de)(de)(de)(de)(de)(de)(de)“電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)”其(qi)實(shi)可以(yi)是(shi)(shi)一(yi)(yi)個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池，也可以(yi)是(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池組或對(dui)于本(ben)(ben)級(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)輸(shu)(shu)出(chu)的(de)(de)(de)(de)(de)(de)(de)(de)前級(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)，而“揚聲器”其(qi)實(shi)就是(shi)(shi)一(yi)(yi)個(ge)用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器，在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong)(zhong)稱(cheng)之(zhi)(zhi)為(wei)(wei)負載。因此，本(ben)(ben)題(ti)其(qi)實(shi)在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)類(lei)課程中(zhong)(zhong)經常(chang)遇到(dao)的(de)(de)(de)(de)(de)(de)(de)(de)負載與(yu)(yu)輸(shu)(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)之(zhi)(zhi)間的(de)(de)(de)(de)(de)(de)(de)(de)功(gong)率匹配問(wen)(wen)(wen)(wen)題(ti)。如(ru)(ru)圖（簡單起見，設電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)與(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)總是(shi)(shi)同相），由閉(bi)合電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)(de)(de)歐(ou)姆定律可知，R獲得的(de)(de)(de)(de)(de)(de)(de)(de)功(gong)率P應(ying)該由R的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)I與(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)U之(zhi)(zhi)積得到(dao)：E，r是(shi)(shi)定值，P視為(wei)(wei)R的(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)(shu)(shu)(shu)(shu)。這(zhe)(zhe)是(shi)(shi)一(yi)(yi)個(ge)分(fen)式函(han)(han)數(shu)(shu)(shu)(shu)(shu)，對(dui)于中(zhong)(zhong)職學(xue)(xue)生而言，求(qiu)其(qi)極值有(you)一(yi)(yi)定難度(du)。而這(zhe)(zhe)個(ge)問(wen)(wen)(wen)(wen)題(ti)是(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)類(lei)課程中(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)基本(ben)(ben)問(wen)(wen)(wen)(wen)題(ti)。這(zhe)(zhe)就要求(qiu)中(zhong)(zhong)職數(shu)(shu)(shu)(shu)(shu)學(xue)(xue)教學(xue)(xue)必(bi)須針(zhen)對(dui)中(zhong)(zhong)職教學(xue)(xue)對(dui)象進行適當(dang)的(de)(de)(de)(de)(de)(de)(de)(de)針(zhen)對(dui)性教學(xue)(xue)。事(shi)實(shi)上(shang)(shang)，對(dui)于分(fen)子(zi)(zi)分(fen)母均為(wei)(wei)多項(xiang)式的(de)(de)(de)(de)(de)(de)(de)(de)分(fen)式函(han)(han)數(shu)(shu)(shu)(shu)(shu)，中(zhong)(zhong)等(deng)數(shu)(shu)(shu)(shu)(shu)學(xue)(xue)里(li)最常(chang)見的(de)(de)(de)(de)(de)(de)(de)(de)處(chu)理(li)(li)方(fang)法就是(shi)(shi)“歸一(yi)(yi)化(hua)”思想。即將多處(chu)出(chu)現的(de)(de)(de)(de)(de)(de)(de)(de)變(bian)量最終(zhong)控(kong)制為(wei)(wei)單一(yi)(yi)變(bian)量在(zai)(zai)一(yi)(yi)處(chu)變(bian)化(hua)。就拿此處(chu)的(de)(de)(de)(de)(de)(de)(de)(de)問(wen)(wen)(wen)(wen)題(ti)來(lai)說，常(chang)見的(de)(de)(de)(de)(de)(de)(de)(de)處(chu)理(li)(li)方(fang)法是(shi)(shi)： 的(de)(de)(de)(de)(de)(de)(de)(de)極值顯然(ran)為(wei)(wei)0，條件(jian)是(shi)(shi)R=r，這(zhe)(zhe)種策略(lve)，在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)物理(li)(li)量的(de)(de)(de)(de)(de)(de)(de)(de)分(fen)析(xi)(xi)計(ji)算中(zhong)(zhong)是(shi)(shi)常(chang)用(yong)(yong)的(de)(de)(de)(de)(de)(de)(de)(de)。3.三角(jiao)函(han)(han)數(shu)(shu)(shu)(shu)(shu)與(yu)(yu)復數(shu)(shu)(shu)(shu)(shu)在(zai)(zai)交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)計(ji)算中(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)運(yun)用(yong)(yong)首先，在(zai)(zai)模(mo)擬電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong)(zhong)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)隨著(zhu)時間變(bian)化(hua)，其(qi)函(han)(han)數(shu)(shu)(shu)(shu)(shu)關系常(chang)常(chang)可以(yi)視為(wei)(wei)三角(jiao)函(han)(han)數(shu)(shu)(shu)(shu)(shu)。三角(jiao)函(han)(han)數(shu)(shu)(shu)(shu)(shu)的(de)(de)(de)(de)(de)(de)(de)(de)基礎(chu)知識(shi)和基本(ben)(ben)運(yun)算在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)相關量的(de)(de)(de)(de)(de)(de)(de)(de)求(qiu)解(jie)中(zhong)(zhong)用(yong)(yong)途很多。比(bi)如(ru)(ru)，那么線路(lu)(lu)(lu)上(shang)(shang)的(de)(de)(de)(de)(de)(de)(de)(de)有(you)用(yong)(yong)功(gong)率其(qi)進一(yi)(yi)步的(de)(de)(de)(de)(de)(de)(de)(de)計(ji)算其(qi)實(shi)就是(shi)(shi)兩(liang)個(ge)三角(jiao)函(han)(han)數(shu)(shu)(shu)(shu)(shu)之(zhi)(zhi)積。其(qi)次，在(zai)(zai)模(mo)擬電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)與(yu)(yu)數(shu)(shu)(shu)(shu)(shu)字電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong)(zhong)都會涉(she)及交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)(de)(de)頻譜分(fen)析(xi)(xi)。其(qi)實(shi)，在(zai)(zai)高等(deng)數(shu)(shu)(shu)(shu)(shu)學(xue)(xue)中(zhong)(zhong)其(qi)實(shi)就是(shi)(shi)一(yi)(yi)個(ge)三角(jiao)級(ji)數(shu)(shu)(shu)(shu)(shu)表示的(de)(de)(de)(de)(de)(de)(de)(de)傅里(li)葉分(fen)析(xi)(xi)，但在(zai)(zai)中(zhong)(zhong)職階段，限于數(shu)(shu)(shu)(shu)(shu)學(xue)(xue)知識(shi)范(fan)圍與(yu)(yu)能力要求(qiu)的(de)(de)(de)(de)(de)(de)(de)(de)限制，不必(bi)講(jiang)解(jie)過(guo)深，但可以(yi)講(jiang)將一(yi)(yi)個(ge)正弦(xian)波函(han)(han)數(shu)(shu)(shu)(shu)(shu)轉化(hua)為(wei)(wei)為(wei)(wei)兩(liang)個(ge)正弦(xian)波函(han)(han)數(shu)(shu)(shu)(shu)(shu)之(zhi)(zhi)積。二、針(zhen)對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)專業的(de)(de)(de)(de)(de)(de)(de)(de)特色，精選現代數(shu)(shu)(shu)(shu)(shu)學(xue)(xue)中(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)淺近內(nei)容，讓(rang)學(xue)(xue)生領悟運(yun)用(yong)(yong)數(shu)(shu)(shu)(shu)(shu)學(xue)(xue)思維的(de)(de)(de)(de)(de)(de)(de)(de)方(fang)法這(zhe)(zhe)方(fang)面是(shi)(shi)傳(chuan)統教材薄弱的(de)(de)(de)(de)(de)(de)(de)(de)地(di)方(fang)，其(qi)實(shi)也是(shi)(shi)本(ben)(ben)課題(ti)應(ying)該大(da)力突破之(zhi)(zhi)處(chu)。1.函(han)(han)數(shu)(shu)(shu)(shu)(shu)的(de)(de)(de)(de)(de)(de)(de)(de)增減(jian)性與(yu)(yu)函(han)(han)數(shu)(shu)(shu)(shu)(shu)“迭代”的(de)(de)(de)(de)(de)(de)(de)(de)思想在(zai)(zai)討論(lun)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)穩定性中(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)運(yun)用(yong)(yong)

電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)或某個(ge)元件的(de)(de)(de)(de)(de)(de)工作狀(zhuang)態是否穩定(ding)(ding)，這(zhe)(zhe)是電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)內(nei)課(ke)程(cheng)中(zhong)常涉(she)及(ji)的(de)(de)(de)(de)(de)(de)問(wen)題(ti)(ti)。在電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)內(nei)課(ke)程(cheng)中(zhong)，常常稱一(yi)個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)學(xue)(xue)量(liang)自身增大（減小(xiao)）時(shi)(shi)其引(yin)起(qi)的(de)(de)(de)(de)(de)(de)本量(liang)或相關(guan)量(liang)變化率為(wei)負(fu)(fu)（正），叫做負(fu)(fu)反饋(kui)，只有(you)負(fu)(fu)反饋(kui)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)才具有(you)穩定(ding)(ding)性。右圖(tu)(tu)(tu)，虛線框內(nei)為(wei)某一(yi)電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)，現在想(xiang)通過實驗觀察它工作的(de)(de)(de)(de)(de)(de)穩定(ding)(ding)性。采(cai)用數(shu)(shu)字取樣測(ce)量(liang)，以某時(shi)(shi)刻的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流為(wei)橫坐(zuo)標，下一(yi)時(shi)(shi)刻的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流為(wei)縱坐(zuo)標，發現畫(hua)出(chu)如圖(tu)(tu)(tu)所示的(de)(de)(de)(de)(de)(de)函數(shu)(shu)圖(tu)(tu)(tu)象，運用“函數(shu)(shu)迭代”的(de)(de)(de)(de)(de)(de)思想(xiang)，從(cong)某一(yi)時(shi)(shi)刻的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流i1開始(shi)，作出(chu)一(yi)系列的(de)(de)(de)(de)(de)(de)輔助線，可見電(dian)(dian)(dian)(dian)(dian)(dian)流最(zui)終(zhong)會穩定(ding)(ding)在i=10mA，當(dang)然，從(cong)純粹(cui)數(shu)(shu)學(xue)(xue)角(jiao)度求解，還有(you)另(ling)一(yi)個(ge)穩定(ding)(ding)點i=0，但結合(he)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)實際情況(kuang)(kuang)，此解應(ying)(ying)該舍去。由此可見，該電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)在不(bu)遠超10mA的(de)(de)(de)(de)(de)(de)情況(kuang)(kuang)下，應(ying)(ying)該是能(neng)夠負(fu)(fu)反饋(kui)的(de)(de)(de)(de)(de)(de)，這(zhe)(zhe)個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)工作狀(zhuang)態是穩定(ding)(ding)的(de)(de)(de)(de)(de)(de)。2.圖(tu)(tu)(tu)論與拓撲知識(shi)(shi)在網絡電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)化簡(jian)(jian)中(zhong)的(de)(de)(de)(de)(de)(de)運用在電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)內(nei)課(ke)程(cheng)中(zhong)，還有(you)一(yi)類問(wen)題(ti)(ti)是很(hen)常見的(de)(de)(de)(de)(de)(de)，那就是電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)簡(jian)(jian)化問(wen)題(ti)(ti)，（專(zhuan)業化的(de)(de)(de)(de)(de)(de)語言是畫(hua)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)等效電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)圖(tu)(tu)(tu)），這(zhe)(zhe)是電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)類學(xue)(xue)生必須(xu)的(de)(de)(de)(de)(de)(de)基本功(gong)，識(shi)(shi)圖(tu)(tu)(tu)、簡(jian)(jian)化圖(tu)(tu)(tu)，才有(you)可能(neng)用好圖(tu)(tu)(tu)，進(jin)而(er)改進(jin)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)設計或進(jin)行功(gong)能(neng)組合(he)。電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)簡(jian)(jian)化時(shi)(shi)，一(yi)般(ban)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)串(chuan)聯、并聯關(guan)系是不(bu)能(neng)隨便改變的(de)(de)(de)(de)(de)(de)。這(zhe)(zhe)種(zhong)問(wen)題(ti)(ti)對于(yu)中(zhong)職學(xue)(xue)生也是頗感頭疼的(de)(de)(de)(de)(de)(de)問(wen)題(ti)(ti)，專(zhuan)業課(ke)教師有(you)時(shi)(shi)教學(xue)(xue)頗費周折。因此中(zhong)職數(shu)(shu)學(xue)(xue)在此疑難點上應(ying)(ying)該突破(po)傳(chuan)統，適當(dang)在數(shu)(shu)學(xue)(xue)科(ke)目教學(xue)(xue)中(zhong)介紹與之相關(guan)的(de)(de)(de)(de)(de)(de)數(shu)(shu)學(xue)(xue)知識(shi)(shi)與技巧(qiao)。

電(dian)(dian)(dian)路的(de)(de)簡(jian)化(hua)問(wen)題(ti)(ti)，用(yong)(yong)(yong)現代(dai)數(shu)(shu)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)的(de)(de)觀(guan)點(dian)來看，其(qi)實(shi)就(jiu)是(shi)(shi)圖(tu)(tu)形(xing)(xing)的(de)(de)拓撲變形(xing)(xing)。右圖(tu)(tu)是(shi)(shi)一(yi)個(ge)網(wang)格電(dian)(dian)(dian)路，P、Q、R、S、T就(jiu)是(shi)(shi)電(dian)(dian)(dian)路的(de)(de)分(fen)支(zhi)點(dian)（拓撲學(xue)(xue)(xue)(xue)(xue)(xue)(xue)中(zhong)(zhong)叫做(zuo)圖(tu)(tu)形(xing)(xing)的(de)(de)頂點(dian)），運(yun)用(yong)(yong)(yong)拓撲變形(xing)(xing)的(de)(de)技(ji)巧，可以變化(hua)為(wei)(wei)另一(yi)個(ge)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)生很容易理(li)(li)解(jie)(jie)的(de)(de)電(dian)(dian)(dian)路圖(tu)(tu)，拓撲學(xue)(xue)(xue)(xue)(xue)(xue)(xue)中(zhong)(zhong)的(de)(de)許多(duo)(duo)概念就(jiu)可以遷移到此問(wen)題(ti)(ti)中(zhong)(zhong)，比(bi)如，電(dian)(dian)(dian)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)中(zhong)(zhong)的(de)(de)電(dian)(dian)(dian)路等(deng)效問(wen)題(ti)(ti)其(qi)實(shi)就(jiu)是(shi)(shi)兩(liang)個(ge)抽(chou)象幾(ji)何圖(tu)(tu)像的(de)(de)拓撲同(tong)構(gou)問(wen)題(ti)(ti)。事實(shi)上，不(bu)僅存在平(ping)面(mian)上的(de)(de)（二維(wei)）電(dian)(dian)(dian)路，在現代(dai)晶體管電(dian)(dian)(dian)路設計中(zhong)(zhong)已(yi)經出(chu)現空(kong)間(jian)的(de)(de)（三(san)維(wei)）電(dian)(dian)(dian)路結(jie)構(gou)。那就(jiu)是(shi)(shi)兩(liang)個(ge)空(kong)間(jian)幾(ji)何結(jie)構(gou)的(de)(de)拓撲同(tong)構(gou)問(wen)題(ti)(ti)。此外，在電(dian)(dian)(dian)子類課程(cheng)(cheng)(cheng)中(zhong)(zhong)，大量(liang)的(de)(de)電(dian)(dian)(dian)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)實(shi)驗(yan)，要想(xiang)簡(jian)捷地通過數(shu)(shu)據(ju)歸(gui)納得出(chu)規律，最(zui)好的(de)(de)辦法就(jiu)是(shi)(shi)繪(hui)制(zhi)恰當(dang)的(de)(de)實(shi)驗(yan)圖(tu)(tu)像。但是(shi)(shi)，圖(tu)(tu)像中(zhong)(zhong)縱軸與橫(heng)軸變量(liang)的(de)(de)選(xuan)(xuan)擇應該(gai)巧妙(miao)，應該(gai)讓圖(tu)(tu)像的(de)(de)截距、斜(xie)率、面(mian)積等(deng)具有一(yi)定的(de)(de)物理(li)(li)意義，便于尋求(qiu)(qiu)相關物理(li)(li)量(liang)的(de)(de)近似數(shu)(shu)值(zhi)解(jie)(jie)，因為(wei)(wei)在電(dian)(dian)(dian)子電(dian)(dian)(dian)路中(zhong)(zhong)，許多(duo)(duo)問(wen)題(ti)(ti)的(de)(de)嚴格求(qiu)(qiu)解(jie)(jie)是(shi)(shi)要解(jie)(jie)常微分(fen)方程(cheng)(cheng)(cheng)或者偏(pian)微分(fen)方程(cheng)(cheng)(cheng)，中(zhong)(zhong)職數(shu)(shu)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)是(shi)(shi)以中(zhong)(zhong)等(deng)數(shu)(shu)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)的(de)(de)應用(yong)(yong)(yong)為(wei)(wei)主，不(bu)能過多(duo)(duo)涉及(ji)高等(deng)數(shu)(shu)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)，所以，圖(tu)(tu)像法求(qiu)(qiu)近似解(jie)(jie)對于中(zhong)(zhong)職學(xue)(xue)(xue)(xue)(xue)(xue)(xue)生求(qiu)(qiu)解(jie)(jie)特殊方程(cheng)(cheng)(cheng)這一(yi)重要技(ji)巧要強化(hua)訓練，形(xing)(xing)成技(ji)能。三(san)、結(jie)語總之(zhi)，不(bu)論傳統中(zhong)(zhong)職數(shu)(shu)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)教學(xue)(xue)(xue)(xue)(xue)(xue)(xue)內容，還是(shi)(shi)精選(xuan)(xuan)現代(dai)數(shu)(shu)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)知識，都要遵循發展(zhan)數(shu)(shu)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)能力尤其(qi)是(shi)(shi)應用(yong)(yong)(yong)數(shu)(shu)學(xue)(xue)(xue)(xue)(xue)(xue)(xue)能力最(zui)為(wei)(wei)核心，“數(shu)(shu)形(xing)(xing)結(jie)合”“化(hua)歸(gui)”“分(fen)類”“動靜(jing)結(jie)合”“化(hua)多(duo)(duo)維(wei)為(wei)(wei)一(yi)維(wei)”等(deng)的(de)(de)思想(xiang)尤其(qi)值(zhi)得重視(shi)。

篇5

1以實驗探究和描點(dian)法作圖為體驗方式的探究性教學

以如(ru)何(he)(he)(he)(he)設(she)(she)計測(ce)量電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)，選擇(ze)什么(me)(me)(me)樣(yang)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)器(qi)材，如(ru)何(he)(he)(he)(he)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)有(you)(you)效(xiao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)記(ji)錄(lu)(lu)，如(ru)何(he)(he)(he)(he)處理(li)(li)(li)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)數(shu)(shu)(shu)據(ju)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)直(zhi)觀的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)(shu)(shu)圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)，這(zhe)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)探究(jiu)(jiu)(jiu)(jiu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)關(guan)鍵．提(ti)高(gao)教學(xue)(xue)(xue)(xue)有(you)(you)效(xiao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)方(fang)(fang)式體現(xian)(xian)(xian)為(wei)(wei)如(ru)何(he)(he)(he)(he)實(shi)(shi)(shi)(shi)施(shi)有(you)(you)效(xiao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)任(ren)務驅動，如(ru)何(he)(he)(he)(he)引(yin)導(dao)(dao)學(xue)(xue)(xue)(xue)生(sheng)(sheng)連接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)、測(ce)量數(shu)(shu)(shu)據(ju)和(he)(he)(he)描(miao)(miao)(miao)點(dian)法(fa)作圖(tu)(tu)(tu)(tu)(tu)，如(ru)何(he)(he)(he)(he)組(zu)(zu)織各(ge)學(xue)(xue)(xue)(xue)習小(xiao)組(zu)(zu)展(zhan)(zhan)(zhan)(zhan)現(xian)(xian)(xian)學(xue)(xue)(xue)(xue)習成(cheng)(cheng)(cheng)(cheng)果(guo)(guo)，為(wei)(wei)此教學(xue)(xue)(xue)(xue)中(zhong)我們(men)應當(dang)(dang)抓住(zhu)如(ru)下(xia)(xia)環(huan)(huan)節(jie):第(di)(di)一(yi)(yi)(yi)個環(huan)(huan)節(jie)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)基(ji)于(yu)(yu)經驗(yan)(yan)(yan)(yan)(yan)(yan)提(ti)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)探究(jiu)(jiu)(jiu)(jiu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)問(wen)題(ti)．要(yao)從(cong)學(xue)(xue)(xue)(xue)生(sheng)(sheng)已有(you)(you)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)認知(zhi)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)發(fa)，形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)可引(yin)導(dao)(dao)學(xue)(xue)(xue)(xue)生(sheng)(sheng)思維(wei)向深度發(fa)展(zhan)(zhan)(zhan)(zhan)，經過一(yi)(yi)(yi)般性(xing)(xing)邏(luo)輯推理(li)(li)(li)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)可探究(jiu)(jiu)(jiu)(jiu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)問(wen)題(ti)，這(zhe)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)問(wen)題(ti)實(shi)(shi)(shi)(shi)施(shi)有(you)(you)效(xiao)探究(jiu)(jiu)(jiu)(jiu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)前提(ti)．為(wei)(wei)此，提(ti)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)如(ru)下(xia)(xia)問(wen)題(ti)來驅動學(xue)(xue)(xue)(xue)生(sheng)(sheng)思維(wei)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)發(fa)展(zhan)(zhan)(zhan)(zhan):當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)R變(bian)(bian)(bian)大(da)時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)P出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)如(ru)何(he)(he)(he)(he)變(bian)(bian)(bian)化(hua)?請同學(xue)(xue)(xue)(xue)們(men)猜猜看，并簡要(yao)談(tan)談(tan)你的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)猜想依(yi)據(ju)!學(xue)(xue)(xue)(xue)生(sheng)(sheng)經過自我探究(jiu)(jiu)(jiu)(jiu)和(he)(he)(he)小(xiao)組(zu)(zu)合作流(liu)(liu)，必然會形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)如(ru)下(xia)(xia)猜想:(1)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)增(zeng)(zeng)大(da)時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)減(jian)小(xiao)，所(suo)(suo)以輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)也(ye)要(yao)隨(sui)之減(jian)少;(2)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)增(zeng)(zeng)大(da)時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)升高(gao)，所(suo)(suo)以輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)要(yao)隨(sui)之增(zeng)(zeng)大(da);(3)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)增(zeng)(zeng)大(da)時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)升高(gao)，而(er)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)要(yao)減(jian)小(xiao)，由公式P=UI可知(zhi)，當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)為(wei)(wei)某(mou)一(yi)(yi)(yi)阻(zu)(zu)(zu)(zu)(zu)(zu)值(zhi)(zhi)時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)應出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)現(xian)(xian)(xian)最大(da)值(zhi)(zhi)．當(dang)(dang)上(shang)述問(wen)題(ti)一(yi)(yi)(yi)一(yi)(yi)(yi)呈現(xian)(xian)(xian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)時(shi)(shi)候(hou)(hou)，為(wei)(wei)了激發(fa)學(xue)(xue)(xue)(xue)生(sheng)(sheng)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)認知(zhi)沖突，我們(men)不(bu)(bu)妨采(cai)(cai)取(qu)“極端法(fa)”來提(ti)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)如(ru)下(xia)(xia)問(wen)題(ti):當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)為(wei)(wei)零(ling)時(shi)(shi)(即短路(lu)(lu)(lu))，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)為(wei)(wei)零(ling);當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)無窮大(da)時(shi)(shi)(即斷(duan)路(lu)(lu)(lu))，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)也(ye)為(wei)(wei)零(ling);當(dang)(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)所(suo)(suo)接上(shang)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)既不(bu)(bu)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)零(ling)又不(bu)(bu)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)無窮大(da)時(shi)(shi)，它輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)功(gong)(gong)(gong)(gong)率(lv)均大(da)于(yu)(yu)零(ling)，那么(me)(me)(me)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)對(dui)外(wai)(wai)(wai)(wai)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)否(fou)(fou)為(wei)(wei)“先增(zeng)(zeng)大(da)后減(jian)小(xiao)”呢?第(di)(di)二(er)個環(huan)(huan)節(jie)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)對(dui)猜想進(jin)(jin)行合理(li)(li)(li)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)評(ping)價(jia)．這(zhe)種(zhong)評(ping)價(jia)不(bu)(bu)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)對(dui)猜想結(jie)果(guo)(guo)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)評(ping)定(ding)，而(er)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)基(ji)于(yu)(yu)探究(jiu)(jiu)(jiu)(jiu)問(wen)題(ti)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)求解(jie)，引(yin)導(dao)(dao)學(xue)(xue)(xue)(xue)生(sheng)(sheng)推演探究(jiu)(jiu)(jiu)(jiu)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)原(yuan)理(li)(li)(li)，這(zhe)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)原(yuan)理(li)(li)(li)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)前提(ti)．同時(shi)(shi)要(yao)在如(ru)何(he)(he)(he)(he)引(yin)導(dao)(dao)學(xue)(xue)(xue)(xue)生(sheng)(sheng)基(ji)于(yu)(yu)探究(jiu)(jiu)(jiu)(jiu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)目的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)設(she)(she)計實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)要(yao)求，并根據(ju)原(yuan)理(li)(li)(li)合理(li)(li)(li)地(di)(di)(di)選擇(ze)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)器(qi)材，進(jin)(jin)行有(you)(you)效(xiao)和(he)(he)(he)安全地(di)(di)(di)安裝，這(zhe)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)實(shi)(shi)(shi)(shi)施(shi)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)操作的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)前提(ti)．測(ce)量什么(me)(me)(me)物理(li)(li)(li)量，探究(jiu)(jiu)(jiu)(jiu)什么(me)(me)(me)，這(zhe)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)基(ji)于(yu)(yu)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)目的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)來設(she)(she)計表(biao)(biao)(biao)格(ge)，進(jin)(jin)而(er)對(dui)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)數(shu)(shu)(shu)據(ju)進(jin)(jin)行記(ji)錄(lu)(lu)、分(fen)析(xi)(xi)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)結(jie)論(lun)(lun)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)前提(ti)．第(di)(di)三(san)個環(huan)(huan)節(jie)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)展(zhan)(zhan)(zhan)(zhan)示(shi)成(cheng)(cheng)(cheng)(cheng)果(guo)(guo)．教師的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)引(yin)導(dao)(dao)應體現(xian)(xian)(xian)在上(shang)述問(wen)題(ti)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)設(she)(she)計和(he)(he)(he)展(zhan)(zhan)(zhan)(zhan)現(xian)(xian)(xian)不(bu)(bu)同學(xue)(xue)(xue)(xue)習小(xiao)組(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)研(yan)究(jiu)(jiu)(jiu)(jiu)成(cheng)(cheng)(cheng)(cheng)果(guo)(guo)上(shang)．包(bao)括展(zhan)(zhan)(zhan)(zhan)示(shi)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)原(yuan)理(li)(li)(li)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)設(she)(she)計、比賽各(ge)學(xue)(xue)(xue)(xue)習小(xiao)組(zu)(zu)連接電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)快慢和(he)(he)(he)優劣(lie)，記(ji)錄(lu)(lu)數(shu)(shu)(shu)據(ju)表(biao)(biao)(biao)格(ge)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)設(she)(she)計，如(ru)何(he)(he)(he)(he)采(cai)(cai)取(qu)描(miao)(miao)(miao)點(dian)法(fa)作圖(tu)(tu)(tu)(tu)(tu)獲得(de)(de)(de)P－R的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)(shu)(shu)圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)，如(ru)何(he)(he)(he)(he)根據(ju)圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)獲得(de)(de)(de)有(you)(you)效(xiao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)結(jie)論(lun)(lun)．找四個小(xiao)組(zu)(zu)利(li)用實(shi)(shi)(shi)(shi)物投影儀投放(fang)記(ji)錄(lu)(lu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)數(shu)(shu)(shu)據(ju)及做出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)P出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)－R圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)．下(xia)(xia)面是(shi)(shi)(shi)(shi)(shi)(shi)(shi)其中(zhong)一(yi)(yi)(yi)個學(xue)(xue)(xue)(xue)習小(xiao)組(zu)(zu)測(ce)量獲得(de)(de)(de)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)數(shu)(shu)(shu)據(ju)表(biao)(biao)(biao)格(ge)(表(biao)(biao)(biao)1)，其中(zhong)r=5．4Ω:第(di)(di)四個環(huan)(huan)節(jie)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)必要(yao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)補(bu)償性(xing)(xing)練習．由于(yu)(yu)所(suo)(suo)學(xue)(xue)(xue)(xue)初等代數(shu)(shu)(shu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)限制(zhi)，我們(men)總(zong)習慣于(yu)(yu)線性(xing)(xing)函(han)(han)數(shu)(shu)(shu)表(biao)(biao)(biao)征物理(li)(li)(li)規(gui)律(lv)，而(er)對(dui)于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)隨(sui)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)變(bian)(bian)(bian)化(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)(shu)(shu)關(guan)系是(shi)(shi)(shi)(shi)(shi)(shi)(shi)非(fei)線性(xing)(xing)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)，為(wei)(wei)了降低描(miao)(miao)(miao)點(dian)法(fa)作圖(tu)(tu)(tu)(tu)(tu)如(ru)何(he)(he)(he)(he)繪制(zhi)P出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)－R圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)這(zhe)一(yi)(yi)(yi)難點(dian)，在描(miao)(miao)(miao)點(dian)法(fa)作圖(tu)(tu)(tu)(tu)(tu)之前我們(men)復(fu)(fu)習回顧電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)路(lu)(lu)(lu)端電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)隨(sui)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)函(han)(han)數(shu)(shu)(shu)變(bian)(bian)(bian)化(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)規(gui)律(lv)就成(cheng)(cheng)(cheng)(cheng)為(wei)(wei)降低這(zhe)一(yi)(yi)(yi)認知(zhi)難點(dian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)前置(zhi)性(xing)(xing)補(bu)償．為(wei)(wei)此我們(men)應當(dang)(dang)復(fu)(fu)習和(he)(he)(he)展(zhan)(zhan)(zhan)(zhan)示(shi)如(ru)下(xia)(xia)內(nei)容:如(ru)圖(tu)(tu)(tu)(tu)(tu)2所(suo)(suo)示(shi)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)，借助電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)－電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)傳感器(qi)得(de)(de)(de)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)U－R圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)．電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)－電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)傳感器(qi)相當(dang)(dang)于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)(biao)和(he)(he)(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)表(biao)(biao)(biao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)作用，它們(men)通(tong)過數(shu)(shu)(shu)據(ju)采(cai)(cai)集(ji)器(qi)和(he)(he)(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)腦相連，可實(shi)(shi)(shi)(shi)施(shi)以圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)形(xing)(xing)(xing)(xing)式表(biao)(biao)(biao)現(xian)(xian)(xian)U－R的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)動態關(guan)系．從(cong)圖(tu)(tu)(tu)(tu)(tu)3可以看出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu):(1)當(dang)(dang)R增(zeng)(zeng)大(da)時(shi)(shi)U也(ye)隨(sui)之非(fei)線性(xing)(xing)增(zeng)(zeng)加;(2)當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)斷(duan)開R∞時(shi)(shi)，U=E;(3)當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)短路(lu)(lu)(lu)時(shi)(shi)U=0，短路(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)I=E/r(一(yi)(yi)(yi)般不(bu)(bu)允許外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)短路(lu)(lu)(lu))．第(di)(di)四個環(huan)(huan)節(jie)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)引(yin)導(dao)(dao)學(xue)(xue)(xue)(xue)生(sheng)(sheng)描(miao)(miao)(miao)點(dian)法(fa)作圖(tu)(tu)(tu)(tu)(tu)，獲得(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)隨(sui)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)變(bian)(bian)(bian)化(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)(shu)(shu)圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)．要(yao)引(yin)導(dao)(dao)學(xue)(xue)(xue)(xue)生(sheng)(sheng)學(xue)(xue)(xue)(xue)會“用平(ping)(ping)滑曲(qu)(qu)線連接”和(he)(he)(he)函(han)(han)數(shu)(shu)(shu)變(bian)(bian)(bian)化(hua)關(guan)系非(fei)線性(xing)(xing)變(bian)(bian)(bian)化(hua)這(zhe)兩(liang)點(dian)，從(cong)而(er)獲得(de)(de)(de)及與(yu)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)數(shu)(shu)(shu)據(ju)真實(shi)(shi)(shi)(shi)可信的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)．通(tong)過對(dui)坐(zuo)(zuo)標(biao)紙上(shang)若干點(dian)用平(ping)(ping)滑曲(qu)(qu)線連線，形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)可直(zhi)觀觀測(ce)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)P出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)－R圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)．在描(miao)(miao)(miao)點(dian)法(fa)作圖(tu)(tu)(tu)(tu)(tu)時(shi)(shi)，為(wei)(wei)了節(jie)約坐(zuo)(zuo)標(biao)紙的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)使用空間，尊(zun)重實(shi)(shi)(shi)(shi)際測(ce)量選擇(ze)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)與(yu)對(dui)應的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)路(lu)(lu)(lu)端電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)數(shu)(shu)(shu)值(zhi)(zhi)，我們(men)在建立坐(zuo)(zuo)標(biao)系的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)時(shi)(shi)候(hou)(hou)，往往是(shi)(shi)(shi)(shi)(shi)(shi)(shi)從(cong)某(mou)一(yi)(yi)(yi)個值(zhi)(zhi)開始，如(ru)圖(tu)(tu)(tu)(tu)(tu)4所(suo)(suo)示(shi)．第(di)(di)五個環(huan)(huan)節(jie)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)基(ji)于(yu)(yu)描(miao)(miao)(miao)點(dian)法(fa)獲得(de)(de)(de)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)如(ru)何(he)(he)(he)(he)進(jin)(jin)行有(you)(you)效(xiao)地(di)(di)(di)分(fen)析(xi)(xi)，這(zhe)既是(shi)(shi)(shi)(shi)(shi)(shi)(shi)提(ti)高(gao)實(shi)(shi)(shi)(shi)驗(yan)(yan)(yan)(yan)(yan)(yan)素養(yang)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)關(guan)鍵，更是(shi)(shi)(shi)(shi)(shi)(shi)(shi)深化(hua)理(li)(li)(li)解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)隨(sui)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)變(bian)(bian)(bian)化(hua)規(gui)律(lv)認知(zhi)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)關(guan)鍵．為(wei)(wei)此通(tong)過任(ren)務驅動的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)方(fang)(fang)式引(yin)導(dao)(dao)學(xue)(xue)(xue)(xue)生(sheng)(sheng)分(fen)組(zu)(zu)進(jin)(jin)行討論(lun)(lun)交流(liu)(liu)得(de)(de)(de)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)結(jie)論(lun)(lun)，這(zhe)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)增(zeng)(zeng)強感知(zhi)獲得(de)(de)(de)豐富表(biao)(biao)(biao)象(xiang)(xiang)(xiang)形(xing)(xing)(xing)(xing)成(cheng)(cheng)(cheng)(cheng)認知(zhi)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)基(ji)礎．(1)根據(ju)計算(suan)和(he)(he)(he)作圖(tu)(tu)(tu)(tu)(tu)分(fen)析(xi)(xi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)與(yu)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)有(you)(you)什么(me)(me)(me)變(bian)(bian)(bian)化(hua)規(gui)律(lv)?(2)當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)增(zeng)(zeng)大(da)時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)是(shi)(shi)(shi)(shi)(shi)(shi)(shi)否(fou)(fou)一(yi)(yi)(yi)味地(di)(di)(di)增(zeng)(zeng)大(da)?(3)當(dang)(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)為(wei)(wei)一(yi)(yi)(yi)定(ding)值(zhi)(zhi)時(shi)(shi)，是(shi)(shi)(shi)(shi)(shi)(shi)(shi)否(fou)(fou)對(dui)應外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)唯一(yi)(yi)(yi)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)阻(zu)(zu)(zu)(zu)(zu)(zu)值(zhi)(zhi)?(4)當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)與(yu)等效(xiao)內(nei)阻(zu)(zu)(zu)(zu)(zu)(zu)相接近時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)為(wei)(wei)最大(da)，是(shi)(shi)(shi)(shi)(shi)(shi)(shi)否(fou)(fou)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)效(xiao)率(lv)也(ye)為(wei)(wei)最大(da)?(5)當(dang)(dang)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)從(cong)零(ling)開始變(bian)(bian)(bian)化(hua)，描(miao)(miao)(miao)繪得(de)(de)(de)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)P出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)－R圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)如(ru)圖(tu)(tu)(tu)(tu)(tu)4所(suo)(suo)示(shi)，試分(fen)析(xi)(xi)描(miao)(miao)(miao)繪得(de)(de)(de)到的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)(shu)(shu)圖(tu)(tu)(tu)(tu)(tu)象(xiang)(xiang)(xiang)在同一(yi)(yi)(yi)個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)時(shi)(shi)為(wei)(wei)什么(me)(me)(me)會出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)現(xian)(xian)(xian)兩(liang)種(zhong)可能的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)值(zhi)(zhi)?(6)同一(yi)(yi)(yi)輸(shu)(shu)(shu)(shu)(shu)出(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)(chu)功(gong)(gong)(gong)(gong)率(lv)對(dui)應的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)值(zhi)(zhi)R1，R2存在什么(me)(me)(me)關(guan)系?(7)分(fen)析(xi)(xi)峰值(zhi)(zhi)所(suo)(suo)對(dui)應外(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)物理(li)(li)(li)意(yi)義?

2以直觀性(xing)觀察為主(zhu)的探究(jiu)性(xing)實驗(yan)

測量數(shu)據(ju)，描(miao)點法(fa)作圖(tu)(tu)(tu)如(ru)圖(tu)(tu)(tu)5，分(fen)(fen)析(xi)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)獲得(de)(de)(de)(de)結論這(zhe)是(shi)(shi)(shi)(shi)常(chang)規(gui)(gui)(gui)(gui)實(shi)(shi)(shi)(shi)驗探(tan)(tan)究的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)基(ji)(ji)本做法(fa)，但由(you)于(yu)本節課要解(jie)決電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)路(lu)(lu)(lu)端電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)，耗時(shi)(shi)較(jiao)多(duo)，如(ru)果再(zai)(zai)通(tong)過(guo)(guo)實(shi)(shi)(shi)(shi)驗操作和(he)數(shu)據(ju)處理(li)(li)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)方(fang)(fang)式獲得(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)關(guan)系不(bu)(bu)(bu)(bu)(bu)(bu)太(tai)現(xian)實(shi)(shi)(shi)(shi)，因(yin)此(ci)利用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)－電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)傳(chuan)感(gan)器(qi)(qi)輸(shu)(shu)(shu)(shu)入(ru)計算(suan)機，繪(hui)制形(xing)(xing)(xing)成(cheng)(cheng)(cheng)P出(chu)(chu)(chu)－R圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)，在(zai)(zai)(zai)(zai)增(zeng)(zeng)強(qiang)直(zhi)觀性(xing)(xing)，提高(gao)可(ke)信(xin)度的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)前提下實(shi)(shi)(shi)(shi)施(shi)實(shi)(shi)(shi)(shi)驗探(tan)(tan)究比較(jiao)可(ke)行．借助(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)－電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)傳(chuan)感(gan)器(qi)(qi)得(de)(de)(de)(de)出(chu)(chu)(chu)P出(chu)(chu)(chu)－R圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)如(ru)圖(tu)(tu)(tu)所(suo)描(miao)繪(hui)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)所(suo)示．2理(li)(li)論探(tan)(tan)究形(xing)(xing)(xing)成(cheng)(cheng)(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)規(gui)(gui)(gui)(gui)律(lv)2．1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)函(han)(han)數(shu)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)如(ru)圖(tu)(tu)(tu)6所(suo)示，在(zai)(zai)(zai)(zai)不(bu)(bu)(bu)(bu)(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)區(qu)間具(ju)有(you)(you)(you)不(bu)(bu)(bu)(bu)(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)單(dan)(dan)調(diao)(diao)性(xing)(xing)(1)當(dang)R=r時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)最(zui)(zui)(zui)大(da)(da)(da)(da)(da)為(wei)Pmax=E2/4r，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)效(xiao)(xiao)率(lv)(lv)(lv)(lv)最(zui)(zui)(zui)高(gao)也(ye)(ye)只是(shi)(shi)(shi)(shi)50%;(2)當(dang)R＜r時(shi)(shi)，函(han)(han)數(shu)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)單(dan)(dan)調(diao)(diao)遞(di)增(zeng)(zeng)，隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)R的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)增(zeng)(zeng)大(da)(da)(da)(da)(da)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)越(yue)(yue)來(lai)越(yue)(yue)大(da)(da)(da)(da)(da)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)效(xiao)(xiao)率(lv)(lv)(lv)(lv)也(ye)(ye)在(zai)(zai)(zai)(zai)增(zeng)(zeng)大(da)(da)(da)(da)(da);(3)當(dang)R＞r時(shi)(shi)，函(han)(han)數(shu)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)單(dan)(dan)調(diao)(diao)遞(di)減(jian)(jian)，隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)R的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)增(zeng)(zeng)大(da)(da)(da)(da)(da)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)越(yue)(yue)來(lai)越(yue)(yue)小，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)效(xiao)(xiao)率(lv)(lv)(lv)(lv)仍在(zai)(zai)(zai)(zai)增(zeng)(zeng)大(da)(da)(da)(da)(da);(5)從函(han)(han)數(shu)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)形(xing)(xing)(xing)狀(zhuang)來(lai)看(kan)，單(dan)(dan)調(diao)(diao)遞(di)增(zeng)(zeng)和(he)單(dan)(dan)調(diao)(diao)遞(di)減(jian)(jian)并(bing)非(fei)關(guan)于(yu)R=r對(dui)(dui)稱．通(tong)過(guo)(guo)上述分(fen)(fen)析(xi)可(ke)知(zhi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)越(yue)(yue)大(da)(da)(da)(da)(da)而(er)其效(xiao)(xiao)率(lv)(lv)(lv)(lv)不(bu)(bu)(bu)(bu)(bu)(bu)一(yi)(yi)(yi)定(ding)(ding)越(yue)(yue)高(gao)．從能量利用(yong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)角度來(lai)看(kan)，我(wo)們(men)(men)(men)希(xi)望電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)效(xiao)(xiao)率(lv)(lv)(lv)(lv)越(yue)(yue)高(gao)越(yue)(yue)好(hao)，但從理(li)(li)論上，這(zhe)要求外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)要增(zeng)(zeng)大(da)(da)(da)(da)(da)，這(zhe)意(yi)味電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)在(zai)(zai)(zai)(zai)不(bu)(bu)(bu)(bu)(bu)(bu)斷減(jian)(jian)小，當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)趨向于(yu)無限大(da)(da)(da)(da)(da)(外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)斷開)時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)減(jian)(jian)小為(wei)零，在(zai)(zai)(zai)(zai)實(shi)(shi)(shi)(shi)際中沒有(you)(you)(you)意(yi)義(yi)，故(gu)在(zai)(zai)(zai)(zai)實(shi)(shi)(shi)(shi)際中利用(yong)同(tong)(tong)一(yi)(yi)(yi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)能量時(shi)(shi)，既要考慮電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)又要兼顧電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)效(xiao)(xiao)率(lv)(lv)(lv)(lv)．電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中涉及到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)定(ding)(ding)性(xing)(xing)分(fen)(fen)析(xi)和(he)定(ding)(ding)量計算(suan)時(shi)(shi)，基(ji)(ji)本思路(lu)(lu)(lu)是(shi)(shi)(shi)(shi)依據(ju)部分(fen)(fen)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)改變(bian)(bian)(bian)(bian)(bian)(bian)(bian)判(pan)(pan)斷總(zong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)，根(gen)據(ju)閉合電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)歐姆定(ding)(ding)律(lv)分(fen)(fen)析(xi)干(gan)路(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)，干(gan)路(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)改變(bian)(bian)(bian)(bian)(bian)(bian)(bian)引起電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)在(zai)(zai)(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)里重新(xin)分(fen)(fen)配，從而(er)使各用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)尾隨(sui)(sui)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)，是(shi)(shi)(shi)(shi)“牽一(yi)(yi)(yi)發而(er)動全身”相互關(guan)聯的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)動態(tai)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)問(wen)(wen)題(ti)．因(yin)此(ci)處理(li)(li)這(zhe)類(lei)(lei)問(wen)(wen)題(ti)遵循的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)原(yuan)則是(shi)(shi)(shi)(shi)不(bu)(bu)(bu)(bu)(bu)(bu)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)優先的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)原(yuan)則，即(ji)先從不(bu)(bu)(bu)(bu)(bu)(bu)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)地方(fang)(fang)入(ru)手(shou)，從而(er)分(fen)(fen)析(xi)研究對(dui)(dui)象(xiang)(xiang)(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)．根(gen)據(ju)實(shi)(shi)(shi)(shi)際場景我(wo)們(men)(men)(men)分(fen)(fen)為(wei)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)和(he)恒(heng)定(ding)(ding)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)兩(liang)類(lei)(lei)．(1)若(ruo)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)阻(zu)(zu)(zu)(zu)(zu)(zu)值(zhi)(zhi)是(shi)(shi)(shi)(shi)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)，通(tong)常(chang)采用(yong)等效(xiao)(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)方(fang)(fang)法(fa)得(de)(de)(de)(de)出(chu)(chu)(chu)E'和(he)r'，實(shi)(shi)(shi)(shi)將用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)獲得(de)(de)(de)(de)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)最(zui)(zui)(zui)大(da)(da)(da)(da)(da)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)問(wen)(wen)題(ti)轉(zhuan)化(hua)(hua)(hua)成(cheng)(cheng)(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)最(zui)(zui)(zui)大(da)(da)(da)(da)(da)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)問(wen)(wen)題(ti)來(lai)處理(li)(li)，當(dang)且僅當(dang)R=r'時(shi)(shi)Pmax=E2/4r';(2)當(dang)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)是(shi)(shi)(shi)(shi)固定(ding)(ding)不(bu)(bu)(bu)(bu)(bu)(bu)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)，我(wo)們(men)(men)(men)通(tong)常(chang)用(yong)P=I2R或者P=U2/R來(lai)求解(jie)．2．2電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)，在(zai)(zai)(zai)(zai)不(bu)(bu)(bu)(bu)(bu)(bu)同(tong)(tong)區(qu)間內單(dan)(dan)調(diao)(diao)性(xing)(xing)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)應(ying)用(yong)求解(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)時(shi)(shi)我(wo)們(men)(men)(men)要判(pan)(pan)斷外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)在(zai)(zai)(zai)(zai)什(shen)么區(qu)間范(fan)圍(wei)內，即(ji)判(pan)(pan)斷外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)在(zai)(zai)(zai)(zai)0≤R≤r和(he)r≤R≤Rmax那個區(qu)間，利用(yong)函(han)(han)數(shu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)單(dan)(dan)調(diao)(diao)性(xing)(xing)求其極(ji)值(zhi)(zhi)(不(bu)(bu)(bu)(bu)(bu)(bu)一(yi)(yi)(yi)定(ding)(ding)是(shi)(shi)(shi)(shi)最(zui)(zui)(zui)值(zhi)(zhi))．也(ye)(ye)就是(shi)(shi)(shi)(shi)說，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)由(you)于(yu)隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)而(er)發生改變(bian)(bian)(bian)(bian)(bian)(bian)(bian)，具(ju)有(you)(you)(you)嚴格的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)單(dan)(dan)調(diao)(diao)性(xing)(xing)才存在(zai)(zai)(zai)(zai)極(ji)值(zhi)(zhi)問(wen)(wen)題(ti);有(you)(you)(you)嚴格的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)有(you)(you)(you)界性(xing)(xing)才存在(zai)(zai)(zai)(zai)最(zui)(zui)(zui)值(zhi)(zhi)問(wen)(wen)題(ti)．(1)當(dang)RA≤r時(shi)(shi)，R1＜R2＜r，P1＜P2≤E24r，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)呈現(xian)單(dan)(dan)調(diao)(diao)遞(di)增(zeng)(zeng)，P出(chu)(chu)(chu)≤E2/4r;(2)當(dang)R≥r時(shi)(shi)，r＜R3＜R4，E24r＞P3＞P4，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)隨(sui)(sui)外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)單(dan)(dan)調(diao)(diao)遞(di)減(jian)(jian)，P出(chu)(chu)(chu)≤E2/4r;因(yin)此(ci)分(fen)(fen)析(xi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)最(zui)(zui)(zui)大(da)(da)(da)(da)(da)輸(shu)(shu)(shu)(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)(gong)(gong)(gong)(gong)率(lv)(lv)(lv)(lv)必須明確外(wai)(wai)(wai)(wai)(wai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)可(ke)能變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)范(fan)圍(wei)，是(shi)(shi)(shi)(shi)在(zai)(zai)(zai)(zai)什(shen)么區(qu)間內，存在(zai)(zai)(zai)(zai)最(zui)(zui)(zui)值(zhi)(zhi)?還是(shi)(shi)(shi)(shi)極(ji)值(zhi)(zhi)?要根(gen)據(ju)函(han)(han)數(shu)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)單(dan)(dan)調(diao)(diao)性(xing)(xing)來(lai)解(jie)決．運用(yong)函(han)(han)數(shu)解(jie)析(xi)式表達物(wu)理(li)(li)規(gui)(gui)(gui)(gui)律(lv)，輔助(zhu)以函(han)(han)數(shu)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)直(zhi)觀呈現(xian)物(wu)理(li)(li)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)規(gui)(gui)(gui)(gui)律(lv)，兩(liang)種(zhong)方(fang)(fang)式并(bing)重才能形(xing)(xing)(xing)成(cheng)(cheng)(cheng)“數(shu)”和(he)“形(xing)(xing)(xing)”一(yi)(yi)(yi)一(yi)(yi)(yi)對(dui)(dui)應(ying)關(guan)系，我(wo)們(men)(men)(men)借助(zhu)于(yu)兩(liang)種(zhong)方(fang)(fang)式才能有(you)(you)(you)效(xiao)(xiao)地把握物(wu)理(li)(li)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)規(gui)(gui)(gui)(gui)律(lv)．對(dui)(dui)于(yu)線性(xing)(xing)函(han)(han)數(shu)以外(wai)(wai)(wai)(wai)(wai)不(bu)(bu)(bu)(bu)(bu)(bu)太(tai)熟悉的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)，在(zai)(zai)(zai)(zai)深(shen)(shen)化(hua)(hua)(hua)理(li)(li)解(jie)變(bian)(bian)(bian)(bian)(bian)(bian)(bian)化(hua)(hua)(hua)規(gui)(gui)(gui)(gui)律(lv)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)時(shi)(shi)候，我(wo)們(men)(men)(men)不(bu)(bu)(bu)(bu)(bu)(bu)要急于(yu)直(zhi)接給出(chu)(chu)(chu)學(xue)生不(bu)(bu)(bu)(bu)(bu)(bu)太(tai)熟悉的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)函(han)(han)數(shu)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)，而(er)是(shi)(shi)(shi)(shi)要遵循認知(zhi)發展的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)規(gui)(gui)(gui)(gui)律(lv)，必須通(tong)過(guo)(guo)實(shi)(shi)(shi)(shi)驗探(tan)(tan)究獲得(de)(de)(de)(de)科學(xue)有(you)(you)(you)效(xiao)(xiao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)數(shu)據(ju)，通(tong)過(guo)(guo)描(miao)點法(fa)作圖(tu)(tu)(tu)逐步得(de)(de)(de)(de)到(dao)函(han)(han)數(shu)圖(tu)(tu)(tu)象(xiang)(xiang)(xiang)(xiang)(xiang)．這(zhe)種(zhong)方(fang)(fang)式雖然在(zai)(zai)(zai)(zai)學(xue)習(xi)(xi)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)過(guo)(guo)程中有(you)(you)(you)點慢，但它符合學(xue)習(xi)(xi)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)認知(zhi)規(gui)(gui)(gui)(gui)律(lv)，即(ji)能通(tong)過(guo)(guo)實(shi)(shi)(shi)(shi)驗探(tan)(tan)究獲得(de)(de)(de)(de)豐富的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)感(gan)知(zhi)，形(xing)(xing)(xing)成(cheng)(cheng)(cheng)有(you)(you)(you)效(xiao)(xiao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)表象(xiang)(xiang)(xiang)(xiang)(xiang)，基(ji)(ji)于(yu)此(ci)才能進行有(you)(you)(you)效(xiao)(xiao)地抽(chou)象(xiang)(xiang)(xiang)(xiang)(xiang)形(xing)(xing)(xing)成(cheng)(cheng)(cheng)真實(shi)(shi)(shi)(shi)可(ke)信(xin)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)規(gui)(gui)(gui)(gui)律(lv)．當(dang)我(wo)們(men)(men)(men)獲得(de)(de)(de)(de)這(zhe)一(yi)(yi)(yi)規(gui)(gui)(gui)(gui)律(lv)時(shi)(shi)，再(zai)(zai)通(tong)過(guo)(guo)必要的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)理(li)(li)論探(tan)(tan)究進行驗證，我(wo)們(men)(men)(men)就形(xing)(xing)(xing)成(cheng)(cheng)(cheng)了“數(shu)”與“形(xing)(xing)(xing)”對(dui)(dui)應(ying)，可(ke)直(zhi)觀呈現(xian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)物(wu)理(li)(li)規(gui)(gui)(gui)(gui)律(lv)．再(zai)(zai)通(tong)過(guo)(guo)相近(jin)概念的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)區(qu)別和(he)相關(guan)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)應(ying)用(yong)，就能達到(dao)知(zhi)識的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)深(shen)(shen)化(hua)(hua)(hua)理(li)(li)解(jie)，唯有(you)(you)(you)如(ru)此(ci)我(wo)們(men)(men)(men)的(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)(de)教學(xue)才能稱之(zhi)為(wei)有(you)(you)(you)效(xiao)(xiao)!

作(zuo)者：邢洪(hong)明 高翔(xiang) 單位：青島(dao)第二中學