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webadm
投稿日時: 2007-11-1 10:56
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登録日: 2004-11-7
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投稿: 3012
問題65:電力伝送と整合(その3)
今度は異なる電圧と内部抵抗をもつ2つの電源のある回路での整合の問題。



負荷抵抗で消費する電力を最大にする負荷抵抗値を求めそのときの電力を導くもの。

基本的に負荷抵抗に流れる電流(I)を導いて、最終的な消費電力(P)が最大となるRLを求めた後、その時の消費電力をそのRLを代入して求めれば良い。

負荷抵抗に流れる電流(I)を求めるいくつか解法があると思われる。ひとつは著者の様に網目電流法を使って負荷抵抗に流れる電流の式を導くもの。もうひとつは枝電流法によるもの。更に後に出てくる重ね合わせやテブナンの定理を用いて単一の等価電圧源を求めるという方法。

ここでは著者と異なる枝電流法によって求めてみる。

図より未知数のI,I1に関する以下の方程式を立てることができる

(%i4) e1: RL*I+(I-I1)*R2=E2;
(%o4) I*RL+(I-I1)*R2=E2

(%i5) e2: RL*I+R1*I1=E1;
(%o5) I*RL+I1*R1=E1

これをI,I1について解くと

(%i6) solve([e1,e2],[I,I1]);
(%o6) [[I=(E1*R2+E2*R1)/((R2+R1)*RL+R1*R2),I1=-((E2-E1)*RL-E1*R2)/((R2+R1)*RL+R1*R2)]]

ということでIが求まる。このIを以下の負荷抵抗の消費電力の式に代入すると

P=I^2*RL=((E1*R2+E2*R1)/(R2*RL+R1*RL+R1*R2))^2*RL

これをRLに関して微分すると

(%i11) diff(((E1*R2+E2*R1)/(R2*RL+R1*RL+R1*R2))^2*RL,RL);
(%o11) (E1*R2+E2*R1)^2/(R2*RL+R1*RL+R1*R2)^2-(2*(R2+R1)*(E1*R2+E2*R1)^2*RL)/(R2*RL+R1*RL+R1*R2)^3

(%i12) factor(%);

(%o12) -((E1*R2+E2*R1)^2*(R2*RL+R1*RL-R1*R2))/(R2*RL+R1*RL+R1*R2)^3

ということで微分係数の分子が0となるRLが電力Pが最大値を取る点であるので

R2*RL+R1*RL-R1*R2=0

となるRLを求めると

(%i13) solve(R2*RL+R1*RL-R1*R2=0,RL);
(%o13) [RL=(R1*R2)/(R2+R1)]

となる

これをPの式に代入すれば最大の電力が求まる

(%i14) Pm=((E1*R2+E2*R1)/(R2*RL+R1*RL+R1*R2))^2*RL;
(%o14) Pm=((E1*R2+E2*R1)^2*RL)/(R2*RL+R1*RL+R1*R2)^2

(%i15) subst((R1*R2)/(R2+R1), RL, Pm=((E1*R2+E2*R1)^2*RL)/(R2*RL+R1*RL+R1*R2)^2);
(%o15) Pm=(R1*R2*(E1*R2+E2*R1)^2)/((R2+R1)*((R1*R2^2)/(R2+R1)+(R1^2*R2)/(R2+R1)+R1*R2)^2)

(%i16) factor(%);

(%o16) Pm=(E1*R2+E2*R1)^2/(4*R1*R2*(R2+R1))

ということで著者と同じ結果が得られる。
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題名 投稿者 日時
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     格子状抵抗ネットワークの意味 webadm 2007-2-4 21:13
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           実学と理論 webadm 2007-2-22 6:56
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                             問題14:3つのΔ接続ワイヤー網 webadm 2007-3-9 5:54
                               問題15:アッテネーターぽい回路 webadm 2007-3-23 11:59
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                                   問題17、18、19 webadm 2007-3-24 22:55
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                                       問題22:電流計 webadm 2007-3-26 11:39
                                         問題23:電流計と電圧計 webadm 2007-3-26 12:03
                                           問題24:T型アッテネーター webadm 2007-3-27 11:19
                                             問題25:パイ型アッテネーター webadm 2007-3-30 19:49
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                                                 Re: 問題25:パイ型アッテネーター webadm 2007-4-12 21:44
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                                                       問題30:ブリッジ回路解析 webadm 2007-8-26 12:05
                                                         Re: 問題30:ブリッジ回路解析 webadm 2007-8-26 22:25
                                                           Maxima超便利 webadm 2007-8-27 1:16
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                                                               問題31:ブリッジの逆接続 webadm 2007-8-30 20:03
                                                                 問題32:剣流計の内部抵抗が0のブリッジ回路 webadm 2007-8-30 20:21
                                                                   問題33:平衡ブリッジによる抵抗測定 webadm 2007-9-1 11:16
                                                                     問題34:ひねったブリッジ回路 webadm 2007-9-5 14:27
                                                                       問題35:内部抵抗がない剣流計を流れる電流 webadm 2007-9-6 8:42
                                                                         問題36:バイパスされたT型アッテネーター webadm 2007-9-15 3:54
                                                                           問題37:Kelvinのダブルブリッジ webadm 2007-9-15 18:10
                                                                             問題38:地絡距離測定 webadm 2007-9-15 19:36
                                                                               問題39:キャパシタの並列接続 webadm 2007-9-21 19:33
                                                                                 問題40:キャパシタの直列接続 webadm 2007-9-21 19:53
                                                                                   問題41:コンデンサの直列接続計算 webadm 2007-9-22 3:54
                                                                                     問題42:コンデンサの直・並列組み合わせ回路計算 webadm 2007-9-22 19:26
                                                                                       問題43:コンデンサのY接続 webadm 2007-9-23 3:31
                                                                                         問題44:コンデンサーのラダー回路 webadm 2007-9-23 4:42
                                                                                           問題45:充電済みコンデンサの並列接続 webadm 2007-9-23 5:21
                                                                                             問題46:充電済みコンデンサの並列接続(その2) webadm 2007-9-24 8:27
                                                                                               問題47:充電済みコンデンサの並列接続(その3) webadm 2007-9-24 9:41
                                                                                                 問題48:変わり種ブリッジ回路 webadm 2007-9-24 10:18
                                                                                                   問題49:電圧を殺す webadm 2007-9-25 5:26
                                                                                                     問題50:偏微分を使った回路解析 webadm 2007-9-27 21:39
                                                                                                       Re: 問題50:偏微分を使った回路解析 webadm 2007-9-28 5:47
                                                                                                       問題51:偏微分を使った回路解析(その2) webadm 2007-9-28 9:45
                                                                                                         問題52:偏微分を使った回路解析(その3) webadm 2007-9-28 11:56
                                                                                                           問題53:ちょっとひねった回路解析 webadm 2007-9-29 6:01
                                                                                                             問題54:ちょっとひねった回路解析(その2) webadm 2007-9-29 19:30
                                                                                                               問題55:ちょっとひねった回路解析(その3) webadm 2007-9-30 2:12
                                                                                                                 問題56:ちょっとひねった回路解析(その4) webadm 2007-9-30 22:24
                                                                                                                   問題57:無限に続く抵抗ラダー回路の解析 webadm 2007-10-3 12:16
                                                                                                                     Re: 問題57:無限に続く抵抗ラダー回路の解析 webadm 2007-10-5 8:30
                                                                                                                       Re: 問題57:無限に続く抵抗ラダー回路の解析 webadm 2007-10-7 3:17
                                                                                                                         Re: 問題57:無限に続く抵抗ラダー回路の解析 webadm 2007-10-7 3:30
                                                                                                                           Re: 問題57:無限に続く抵抗ラダー回路の解析 webadm 2007-10-7 22:30
                                                                                                                             Re: 問題57:無限に続く抵抗ラダー回路の解析 webadm 2007-10-8 5:26
                                                                                                                               問題58:n箇所つながった銅線回路 webadm 2007-10-8 11:12
                                                                                                                                 Re: 問題58:n箇所つながった銅線回路 webadm 2007-10-8 22:24
                                                                                                                                   Re: 問題58:n箇所つながった銅線回路 webadm 2007-10-9 10:27
                                                                                                                                     Re: 問題58:n箇所つながった銅線回路 webadm 2007-10-9 22:18
                                                                                                                                       Re: 問題58:n箇所つながった銅線回路 webadm 2007-10-10 4:19
                                                                                                                                         問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-10 5:33
                                                                                                                                           Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-11 3:06
                                                                                                                                             Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-11 4:12
                                                                                                                                               Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-11 5:02
                                                                                                                                                 Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-16 18:24
                                                                                                                                                 Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-17 9:39
                                                                                                                                                   Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-22 0:12
                                                                                                                                                     Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-25 22:12
                                                                                                                                                       Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-26 4:13
                                                                                                                                                         Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-26 4:28
                                                                                                                                                           Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-26 20:24
                                                                                                                                                             Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-26 20:49
                                                                                                                                                               Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-27 11:05
                                                                                                                                                                 Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-27 20:53
                                                                                                                                                                   Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-29 1:45
                                                                                                                                                                     Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-29 10:07
                                                                                                                                                                       Re: 問題59:漏洩抵抗のある架線を流れる電流 webadm 2007-10-30 4:48
                                                                                                                                                                         問題60:短くした電熱線の消費電力 webadm 2007-10-30 9:38
                                                                                                                                                                           問題61:細く短くした電熱線の消費電力 webadm 2007-10-30 10:18
                                                                                                                                                                             問題62:2つの異なる電球を直列につなぐ webadm 2007-10-31 10:39
                                                                                                                                                                               問題63:電力伝送と整合 webadm 2007-10-31 11:07
                                                                                                                                                                                 問題64:電力伝送と整合(その2) webadm 2007-11-1 10:26
                                                                                                                                                                                 » 問題65:電力伝送と整合(その3) webadm 2007-11-1 10:56
                                                                                                                                                                                     問題66:電池の起電力と内部抵抗を求める webadm 2007-11-1 11:25
                                                                                                                                                                                       問題67:配線抵抗のある電力伝送回路 webadm 2007-11-7 9:49
                                                                                                                                                                                         問題68:電力伝送とマッチング(電源側) webadm 2007-11-7 10:17
                                                                                                                                                                                           問題69:カロリーと電力 webadm 2007-11-7 10:49
                                                                                                                                                                                             問題70:電力量と比熱と融点の応用(フューズ) webadm 2007-11-8 10:54
                                                                                                                                                                                               問題71:電力量と比熱と融点の応用(フューズ)の続き webadm 2007-11-8 11:02
                                                                                                                                                                                                 問題72:合成温度係数 webadm 2007-11-8 11:20
                                                                                                                                                                                                   問題73:抵抗値による温度測定 webadm 2007-11-8 11:40
                                                                                                                                                                                                     問題74:温度係数 webadm 2007-11-8 12:45
                                                                                                                                                                                                       Re: 問題74:温度係数 webadm 2007-11-8 14:07
                                                                                                                                                                                                         Re: 問題74:温度係数 webadm 2007-11-8 14:38
                                                                                                                                                                                                           問題75:膨張係数と温度係数 webadm 2007-11-10 11:29
                                                                                                                                                                                                             問題76:導線の温度上昇 webadm 2007-11-11 13:15
                                                                                                                                                                                                               問題77:温度補償抵抗回路 webadm 2007-11-11 23:25
                                                                             Re: 問題37:Kelvinのダブルブリッジ webadm 2007-9-26 7:48
                                                 Re: 問題26:検流計の内部抵抗を求める Anonymous 2007-5-26 2:32
                                                   Re: 問題26:検流計の内部抵抗を求める webadm 2007-5-26 21:00
                                     誤植発見 webadm 2007-3-25 13:07

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