ãã®èšäºã§ã¯RLçŽååè·¯ã®ãåŸ®åæ¹çšåŒã«ããéæž¡çŸè±¡ã®è§£ãæ¹ãã«ã€ããŠèª¬æããŠããŸãã
åããããã説æããããã«ãå³ãå€ãçšããŠãããåŒã®å°åºéçšã现ããæžãããã«æèããŠããŸãã
ãRLçŽååè·¯ããéæž¡çŸè±¡ãã®åŒãšã°ã©ã
äžå³ã¯æµæ\(R{\mathrm{[Ω]}}\)ãã€ã³ãã¯ã¿\(L{\mathrm{[H]}}\)ãçŽæµé»æº\(E{\mathrm{[V]}}\)ãã¹ã€ãã\(SW\)ãããªãRLçŽååè·¯ã§ãã
ãã®èšäºã§ã¯ã以äžã®æ¡ä»¶ã«ããããéæž¡çŸè±¡ãã®åŒãå°åºããŸãã
æ¡ä»¶
- ã¹ã€ãã\(SW\)ããªã³ããæã®æé\(t\)ã\(t=0{\mathrm{[s]}}\)ãšããã
ã¹ã€ãã\(SW\)ããªã³ãããšã以äžã®éæž¡çŸè±¡ãçããŸãã
- 黿µ\(i(t)\)ã\(0{\mathrm{[A]}}\)ããå¢å ããã
- ããçšåºŠæéãçµéãããšã黿µ\(i(t)\)ã®å€åããªããªããäžå®å€\(\displaystyle\frac{E}{R}{\mathrm{[A]}}\)ãšãªãããŸãããã®æãã€ã³ãã¯ã¿\(L\)ãç絡ããããããªç¶æ ã§ãããæµæ\(R\)ã®é»å§\(v_{R}(t)\)ã黿ºé»å§ã®é»å§\(E\)ãšçãããªãã
ãã®æã黿µ\(i(t)\)ãäžå®å€\(\displaystyle\frac{E}{R}{\mathrm{[A]}}\)ãšãªã£ãç¶æ ããå®åžžç¶æ ãããå®åžžç¶æ ãã«è³ããŸã§ã®ç¶æ ããéæž¡ç¶æ ãããã®éçšã§èŠãããçŸç¶ããéæž¡çŸè±¡ããšãããŸãã
ãŸããRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ãæµæ\(R\)ã®é»å§\(v_{R}(t)\)ãã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã®åŒãšã°ã©ãã¯äžèšãšãªããŸãã
\begin{eqnarray}
i(t)&=&\frac{E}{R}\left(1-e^{-\frac{R}{L}t}\right)\\
v_{R}(t)&=&E\left(1-e^{-\frac{R}{L}t}\right)\\
v_{L}(t)&=&Ee^{-\frac{R}{L}t}
\end{eqnarray}
ãã®èšäºã§ã¯äžåŒãåŸ®åæ¹çšåŒãè§£ãæãåºæ¬çã®å€æ°åé¢åœ¢ã®åŸ®åæ¹çšåŒã§è§£ããŠãããŸãããªããäžåŒã¯ã©ãã©ã¹å€æã§ãè§£ãããšãã§ããŸãã
ã©ãã©ã¹å€æã§è§£ãæ¹æ³ã«ã€ããŠã¯ä»¥äžã®èšäºã«è©³ãã説æããŠããŸãã®ã§ãåèã«ããŠãã ããã
-
ãRLçŽååè·¯ã®ã©ãã©ã¹å€æããéæž¡çŸè±¡ãã®è§£ãæ¹ïŒ
ç¶ããèŠã
ãRLçŽååè·¯ããåŸ®åæ¹çšåŒãã®è§£ãæ¹
ãRLçŽååè·¯ã黿µi(t)ã®æ±ãæ¹
RLçŽååè·¯ã«ãã«ããããã®é»å§å(ãã«ããããã®ç¬¬äºæ³å)ãçšãããšæ¬¡åŒãæãç«ã¡ãŸãã
\begin{eqnarray}
E=v_{R}(t)+v_{L}(t)\tag{1}
\end{eqnarray}
(1)åŒã«ãããŠãæµæ\(R\)ã®é»å§\(v_{R}(t)\)ãšã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã¯æ¬¡åŒã§è¡šãããŸãã
\begin{eqnarray}
v_{R}(t)&=&Ri(t)\tag{2}\\
v_{L}(t)&=&L\frac{di(t)}{dt}\tag{3}
\end{eqnarray}
(2)åŒãš(3)åŒã(1)åŒã«ä»£å ¥ãããšã次åŒãåŸãããŸãã
\begin{eqnarray}
E&=&v_{R}(t)+v_{L}(t)\\
&=&Ri(t)+L\frac{di(t)}{dt}\tag{4}
\end{eqnarray}
(4)åŒã¯RLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã«é¢ãããåŸ®åæ¹çšåŒãã§ãã
ãã®ãåŸ®åæ¹çšåŒããè§£ããšãRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ãå°åºããããšãã§ããæ¬¡åŒã®ææ°é¢æ°ãšãªããŸã(次åŒã®å°åºæ¹æ³ã«ã€ããŠã¯ãå°åºéçšãããªãé·ããªãããããã®èšäºã®åŸåã«è©³ãã説æããŠããŸã)ã
i(t)=\frac{E}{R}\left(1-e^{-\frac{R}{L}t}\right)\tag{5}
\end{eqnarray}
ãRLçŽååè·¯ã黿µi(t)ã®ã°ã©ã
RLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã®ã°ã©ãã¯äžå³ã®ããã«ãªããŸãããã®ã°ã©ãã«ã€ããŠèª¬æããŸãã
ç¹°ãè¿ãã«ãªããŸãããRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã®åŒã¯æ¬¡åŒãšãªããŸãã
i(t)=\frac{E}{R}\left(1-e^{-\frac{R}{L}t}\right)\tag{5}
\end{eqnarray}
(5)åŒã®\(t\)ã«ã\(t=0\)ããšã\(t=â\)ããä»£å ¥ããæãèããŠã¿ãŸãããã
ãt=0ããä»£å ¥ããæ
ã\(t=0\)ããä»£å ¥ãããšã(5)åŒã¯æ¬¡åŒãšãªããŸãã
\begin{eqnarray}
i(0)&=&\frac{E}{R}\left(1-e^{-\frac{R}{L}Ã0}\right)\\
&=&\frac{E}{R}\left(1-e^{0}\right)\\
&=&\frac{E}{R}\left(1-1\right)\\
&=&0\tag{6}
\end{eqnarray}
ã€ãŸãã\(t=0\)ãã®æãRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã¯ã\(i(0)=0\)ããšãªããŸãã
ããã¯ãã¹ã€ãã\(SW\)ããªã³ããç¬éãã€ã³ãã¯ã¿\(L\)ã¯éæŸããããããªç¶æ ã§ãããšããããšã衚ããŠããŸãã
ãt=âããä»£å ¥ããæ(å®åžžç¶æ ã®æ)
ã\(t=â\)ããä»£å ¥ãããšã(5)åŒã¯æ¬¡åŒãšãªããŸãã
\begin{eqnarray}
i(t)&=&\frac{E}{R}\left(1-e^{-\frac{R}{L}Ãâ}\right)\\
&=&\frac{E}{R}\left(1-e^{-â}\right)\\
&=&\frac{E}{R}\left(1-\frac{1}{e^{â}}\right)\\
&=&\frac{E}{R}\left(1-0\right)\\
&=&\frac{E}{R}\tag{7}
\end{eqnarray}
ã€ãŸããã\(t=â\)ãã®æãRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã¯ã\(i(â)=\displaystyle\frac{E}{R}\)ããšãªããŸãã
ããã¯ãã¹ã€ãã\(SW\)ããªã³ãããã°ããæéãçµéãããšãã€ã³ãã¯ã¿\(L\)ã¯ç絡ããããããªç¶æ ã§ãããæµæ\(R\)ã«ãã£ãŠRLçŽååè·¯ã«æµãã黿µãå¶éãããŠãããšããããšã衚ããŠããŸãã
ãããã£ãŠãRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã®ã°ã©ãã¯ã\(i(0)=0\)ãããã\(i(â)=\displaystyle\frac{E}{R}\)ãã«ãªãããã«å¢å ããŠããã®ã§ããããã®å¢å å ·åã¯ãã€ã³ãã¯ã¿\(L\)Ã·æµæ\(R\)=\(\displaystyle\frac{L}{R}\)ãã®å€ã«ãã£ãŠå€ãããŸãã
ãã®ã\(\displaystyle\frac{L}{R}\)ã¯äžè¬çã«æå®æ°Ï(ã¿ãŠ)ãšåŒã°ããŠããŸãã
æå®æ°Ï(ã¿ãŠ)ã¯éæž¡çŸè±¡ãã©ã®ãããç¶ãã®ãã衚ãç®å®ã衚ããŠãããåäœã¯[s]ãšãªããŸãã
ä»åã®RLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã®ã°ã©ãã®å Žåãã\({\tau}=\displaystyle\frac{L}{R}\)ãã®å€§ããã«ãã£ãŠä»¥äžã®ããã«å€ãããŸãã
- ã\({\tau}=\displaystyle\frac{L}{R}\)ãã倧ããæ
- ã\({\tau}=\displaystyle\frac{L}{R}\)ããå°ããæ
éæž¡çŸè±¡ãé·ãç¶ããŸãã
éæž¡çŸè±¡ãæ©ãçµãããŸããããªãã¡ãæ©ãå®åžžç¶æ ãšãªããŸãã
ãŸããæétãæå®æ°Ï(ã¿ãŠ)ãšçãããªãæãRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã¯ä»¥äžã®å€ãšãªããŸãã
- ã\(t={\tau}=\displaystyle\frac{L}{R}\)ãã®æ
- ã\(t=4{\tau}=4\displaystyle\frac{L}{R}\)ãã®æ
ã\(\displaystyle\frac{E}{R}\)ãã®çŽ63ïŒ
ã\(\displaystyle\frac{E}{R}\)ãã®çŽ98ïŒ
ãRLçŽååè·¯ãæµæRã®é»å§VR(t)ã®æ±ãæ¹
RLçŽååè·¯ã«æµãã黿µ\(i(t)\)ãåãããšãæµæ\(R\)ã®é»å§\(v_{R}(t)\)ãç°¡åã«æ±ããããšãã§ããŸãã
(5)åŒã(2)åŒã«ä»£å ¥ãããšãæµæ\(R\)ã®é»å§\(v_{R}(t)\)ã¯æ¬¡åŒãšãªããŸãã
v_{R}(t)&=&Ri(t)\\
&=&E\left(1-e^{-\frac{R}{L}t}\right)\tag{8}
\end{eqnarray}
ãRLçŽååè·¯ãæµæRã®é»å§VR(t)ã®ã°ã©ã
æµæ\(R\)ã®é»å§\(v_{R}(t)\)ã®ã°ã©ãã¯äžå³ã®ããã«ãªããŸãããã®ã°ã©ãã«ã€ããŠèª¬æããŸãã
ãã®ã°ã©ãã§ãããæµæ\(R\)ã®é»å§\(v_{R}(t)\)ã¯RLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã«\(R\)ãæããã ãã§ãã
ããªãã¡ãRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã®ã°ã©ããšåããããªã°ã©ããšãªããŸãã
ã¹ã€ãã\(SW\)ããªã³ããç¬éãã€ã³ãã¯ã¿\(L\)ã¯éæŸããããããªç¶æ ã§ãããããæµæ\(R\)ã«ãããé»å§ããŒãã«ãªãããšã衚ããŠããŸãã
ã¹ã€ãã\(SW\)ããªã³ãããã°ããæéãçµéãããšãã€ã³ãã¯ã¿\(L\)ã¯ç絡ããããããªç¶æ ã§ãããããæµæ\(R\)ã«çŽæµé»æºã®é»å§\(E\)ã®å šé»å§ãããããšããããšã衚ããŠããŸãã
ãRLçŽååè·¯ãã€ã³ãã¯ã¿Lã®é»å§VL(t)ã®æ±ãæ¹
ã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã¯ãã«ããããã®é»å§å(ãã«ããããã®ç¬¬äºæ³å)ãçšãããšç°¡åã«æ±ããããšãã§ããŸãã
(2)åŒãå€åœ¢ãããšã次åŒãšãªããŸãã
\begin{eqnarray}
&&E=v_{R}(t)+v_{L}(t)\\
{\Leftrightarrow}&&v_{L}(t)=E-v_{R}(t)\tag{9}
\end{eqnarray}
(9)åŒã«(8)åŒãä»£å ¥ãããšãã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã¯æ¬¡åŒãšãªããŸãã
v_{L}(t)&=&E-v_{R}(t)\\
&=&E-E\left(1-e^{-\frac{R}{L}t}\right)\\
&=&E-E+Ee^{-\frac{R}{L}t}\\
&=&Ee^{-\frac{R}{L}t}\tag{10}
\end{eqnarray}
ãRLçŽååè·¯ãã€ã³ãã¯ã¿Lã®é»å§VL(t)ã®ã°ã©ã
ã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã®ã°ã©ãã¯äžå³ã®ããã«ãªããŸãããã®ã°ã©ãã«ã€ããŠèª¬æããŸãã
ç¹°ãè¿ãã«ãªããŸãããã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã®åŒã¯æ¬¡åŒãšãªããŸãã
v_{L}(t)=Ee^{-\frac{R}{L}t}\tag{10}
\end{eqnarray}
(10)åŒã®\(t\)ã«ã\(t=0\)ããšã\(t=â\)ããä»£å ¥ããæãèããŠã¿ãŸãããã
ãt=0ããä»£å ¥ããæ
ã\(t=0\)ããä»£å ¥ãããšã(10)åŒã¯æ¬¡åŒãšãªããŸãã
\begin{eqnarray}
v_{L}(0)&=&Ee^{-\frac{R}{L}Ã0}\\
&=&Ee^{0}\\
&=&E\tag{11}
\end{eqnarray}
ã€ãŸãã\(t=0\)ãã®æãã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã¯ã\(v_{L}(0)=E\)ããšãªããŸãã
ããã¯ãã¹ã€ãã\(SW\)ããªã³ããç¬éãã€ã³ãã¯ã¿\(L\)ã¯éæŸããããããªç¶æ ã§ãããããã€ã³ãã¯ã¿\(L\)ã«çŽæµé»æºã®é»å§\(E\)ã®å šé»å§ãããããšããããšã衚ããŠããŸãã
ãt=âããä»£å ¥ããæ(å®åžžç¶æ ã®æ)
ã\(t=â\)ããä»£å ¥ãããšã(10)åŒã¯æ¬¡åŒãšãªããŸãã
\begin{eqnarray}
v_{L}(â)&=&Ee^{-\frac{R}{L}Ãâ}\\
&=&Ee^{-â}\\
&=&E\frac{1}{e^{â}}\\
&=&EÃ0\\
&=&0\tag{12}
\end{eqnarray}
ã€ãŸããã\(t=â\)ãã®æãã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã¯ã\(v_{L}(â)=0\)ããšãªããŸãã
ããã¯ãã¹ã€ãã\(SW\)ããªã³ãããã°ããæéãçµéãããšãã€ã³ãã¯ã¿\(L\)ã¯ç絡ããããããªç¶æ ã§ãããããã€ã³ãã¯ã¿\(L\)ã«ãããé»å§ããŒãã«ãªãããšã衚ããŠããŸãã
ãããã£ãŠãã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã®ã°ã©ãã¯ã\(v_{L}(0)=E\)ãããã\(v_{L}(â)=0\)ãã«ãªãããã«æžå°ããŠããã®ã§ããããã®æžå°å ·åã¯æå®æ°Ï(ã¿ãŠ)ã«ãã£ãŠå€ãããŸãã
ãŸããæétãæå®æ°Ï(ã¿ãŠ)ãšçãããªãæãã€ã³ãã¯ã¿\(L\)ã®é»å§\(v_{L}(t)\)ã¯ä»¥äžã®å€ãšãªããŸãã
- ã\(t={\tau}=\displaystyle\frac{L}{R}\)ãã®æ
- ã\(t=4{\tau}=4\displaystyle\frac{L}{R}\)ãã®æ
ã\(E\)ãã®çŽ37ïŒ
ã\(E\)ãã®çŽ2ïŒ
ãåŸ®åæ¹çšåŒãã®è§£ãæ¹
ç¹°ãè¿ãã«ãªããŸããã(4)åŒãš(5)åŒãããäžåºŠç€ºããŸãã
(4)åŒã¯RLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã«é¢ãããåŸ®åæ¹çšåŒããšãªã次åŒãšãªããŸãã
\begin{eqnarray}
E=Ri(t)+L\frac{di(t)}{dt}\tag{4}
\end{eqnarray}
ãã®ãåŸ®åæ¹çšåŒããè§£ããšã(5)åŒã®RLçŽååè·¯ã«æµãã黿µ\(i(t)\)ãå°åºããããšãã§ããŸãã
\begin{eqnarray}
i(t)=\frac{E}{R}\left(1-e^{-\frac{R}{L}t}\right)\tag{5}
\end{eqnarray}
ãã®å°åºæ¹æ³ã«ã€ããŠèª¬æããŸãã
å°åºæ¹æ³
ããã§ã¯ãåŸ®åæ¹çšåŒãè§£ãæãåºæ¬çãªãã¿ãŒã³ã®äžã€ã§ããã倿°åé¢åœ¢ã®åŸ®åæ¹çšåŒãã§è§£ããŠãããŸãã
ã倿°åé¢åœ¢ã®åŸ®åæ¹çšåŒããšã¯ãã®åã®éãã倿°ã巊蟺ãšå³èŸºã«åé¢ããåŸ®åæ¹çšåŒã®ããšã§ãã
(4)åŒã®å Žåã黿µ\(i(t)\)ãšæé\(t\)ã倿°ãªã®ã§ã黿µ\(i(t)\)ã«é¢ãããã®ã巊蟺ã«ãæé\(t\)ã«é¢ãããã®ãå³èŸºã«ãªãããã«åé¢ããŸãã
ããªãã¡ã(4)åŒã次åŒã®åœ¢ã«ãªãããã«å€åœ¢ããŸãã
\begin{eqnarray}
â¡di(t)=â¡dt\tag{13}
\end{eqnarray}
å€åœ¢ã¯ä»¥äžã®ããã«è¡ããŸãã
倿°ã巊蟺ãšå³èŸºã«åé¢ããæ¹æ³
ãŸãã(4)åŒã®\(L\displaystyle\frac{di(t)}{dt}\)ã巊蟺ã«ã\(E\)ãå³èŸºã«ç§»åããŠã䞡蟺ã«ãã€ãã¹ãæãããšã次åŒãšãªããŸãã
\begin{eqnarray}
L\frac{di(t)}{dt}=E-Ri(t)\tag{14}
\end{eqnarray}
(14)åŒã®äž¡èŸºã\(L\)ã§å²ããšã次åŒãšãªããŸãã
\begin{eqnarray}
\frac{di(t)}{dt}=\frac{E-Ri(t)}{L}\tag{15}
\end{eqnarray}
(15)åŒã®äž¡èŸºã\(E-Ri(t)\)ã§å²ããšã次åŒãšãªããŸãã
\begin{eqnarray}
\frac{1}{E-Ri(t)}\frac{di(t)}{dt}=\frac{1}{L}\tag{16}
\end{eqnarray}
(16)åŒã®äž¡èŸºã«\(dt\)ãæãããšã次åŒãšãªããŸãã
\begin{eqnarray}
\frac{1}{E-Ri(t)}di(t)=\frac{1}{L}dt\tag{17}
\end{eqnarray}
(17)åŒã®äž¡èŸºã«\(R\)ãæãããšã次åŒãšãªããŸãã
\begin{eqnarray}
\frac{R}{E-Ri(t)}di(t)&=&\frac{R}{L}dt\\
{\Leftrightarrow}\frac{1}{\displaystyle\frac{E}{R}-i(t)}di(t)&=&\frac{R}{L}dt\tag{18}
\end{eqnarray}
以äžããã黿µ\(i(t)\)ã«é¢ãããã®ã巊蟺ã«ãæé\(t\)ã«é¢ãããã®ãå³èŸºã«ãªãããã«åé¢ã§ããŸããã
ããªãã¡ãã\(â¡di(t)=â¡dt\)ãã®åœ¢ã«ãªãããã«å€åœ¢ããããšãã§ããŸããããªããã€ã³ãã¯ã¿\(L\)ãšæµæ\(R\)ãšçŽæµé»æºã®é»å§\(E\)ã¯å®æ°ãªã®ã§ã巊蟺ã«ãã£ãŠãå³èŸºã«ãã£ãŠãã©ã£ã¡ã§ãè¯ãã§ãã
(18)åŒã®äž¡èŸºãç©åãããšã次åŒãšãªããŸãã
\begin{eqnarray}
{\displaystyle\int}\frac{1}{\displaystyle\frac{E}{R}-i(t)}di(t)={\displaystyle\int}\frac{R}{L}dt\tag{19}
\end{eqnarray}
(19)åŒã®å·ŠèŸºãšå³èŸºã¯å¥ã ã«è§£ããŠãããŸãã
巊蟺ã®è§£ãæ¹
ã\(k=\displaystyle\frac{E}{R}-i(t)\)ããšçœ®ããšã\(i(t)\)ã¯RLçŽååè·¯ã«æµããŠãã黿µã§ããã\(\displaystyle\frac{E}{R}\)ã¯å®åžžç¶æ ã«ãããŠRLçŽååè·¯ã«æµããŠãã黿µãªã®ã§ãã\(k=\displaystyle\frac{E}{R}-i(t){≥}0\)ããšãªããŸãã
ãŸããã\(dk=-di(t)\)ããšãªãã®ã§ã(19)åŒã®å·ŠèŸºã¯æ¬¡åŒã®ããã«å€åœ¢ã§ããŸãã
\begin{eqnarray}
(19)åŒã®å·ŠèŸº&=&{\displaystyle\int}\frac{1}{\displaystyle\frac{E}{R}-i(t)}di(t)\\
&=&-{\displaystyle\int}\frac{1}{k}dk\\
&=&-\log_{e}k+A\\
&=&-\log_{e}\left(\displaystyle\frac{E}{R}-i(t)\right)+A\tag{20}
\end{eqnarray}
(20)åŒã«ãããŠã\(A\)ã¯ç©å宿°ãšãªã£ãŠããŸãã
å³èŸºã®è§£ãæ¹
\(\displaystyle\frac{R}{L}\)ã¯å®æ°ãªã®ã§ãç©åã®å€ã«åºãããšãã§ããã®ã§ã(19)åŒã®å³èŸºã¯æ¬¡åŒã®ããã«å€åœ¢ã§ããŸãã
\begin{eqnarray}
(19)åŒã®å³èŸº&=&{\displaystyle\int}\frac{R}{L}dt\\
&=&\frac{R}{L}{\displaystyle\int}dt\\
&=&\frac{R}{L}t+B\tag{21}
\end{eqnarray}
(21)åŒã«ãããŠã\(B\)ã¯ç©å宿°ãšãªã£ãŠããŸãã
(20)åŒãš(21)åŒã(19)åŒã«æ»ããšã次åŒãšãªããŸãã
\begin{eqnarray}
{\displaystyle\int}\frac{1}{\displaystyle\frac{E}{R}-i(t)}di(t)&=&{\displaystyle\int}\frac{R}{L}dt\\
{\Leftrightarrow}-\log_{e}\left(\displaystyle\frac{E}{R}-i(t)\right)+A&=&\frac{R}{L}t+B\tag{22}
\end{eqnarray}
(22)åŒã§ã¯\(A\)ãš\(B\)ã®2ã€ã®ç©å宿°ããããŸããããã§ã\(A-B=D\)ãšçœ®ããšã(22)åŒã¯æ¬¡åŒã®ããã«å€åœ¢ã§ããŸãã
\begin{eqnarray}
\log_{e}\left(\displaystyle\frac{E}{R}-i(t)\right)=-\frac{R}{L}t+D\tag{23}
\end{eqnarray}
(23)åŒãå€åœ¢ãããšã次åŒãšãªããŸãã
\begin{eqnarray}
\displaystyle\frac{E}{R}-i(t)&=&e^{-\frac{R}{L}t+D}\\
&=&e^{-\frac{R}{L}t}Ãe^{D}\tag{24}
\end{eqnarray}
(24)åŒã«ãããŠã\(\displaystyle\frac{E}{R}\)ãå³èŸºã«ç§»åããŠã䞡蟺ã«ãã€ãã¹ãæãããšã次åŒãšãªããŸãã
\begin{eqnarray}
i(t)=\displaystyle\frac{E}{R}-e^{-\frac{R}{L}t}Ãe^{D}\tag{25}
\end{eqnarray}
次ã«ã(25)åŒã®ç©å宿°\(D\)ãæ±ããå¿ èŠããããŸãã
ç©å宿°\(D\)ã¯ä»¥äžã®ããã«æ±ããŸãã
ç©å宿°Dã®æ±ãæ¹
ç©å宿°ã¯åè·¯ã®åææ¡ä»¶ãçšããããšã§æ±ããããšãã§ããŸãã
ãã®åè·¯ã®å Žåãã\(t=0\)ãã®æãããªãã¡ãã¹ã€ãã\(SW\)ããªã³ããç¬éã¯ãRLçŽååè·¯ã«æµãã黿µ\(i(t)\)ã¯ãŒããšãªããŸãã
ãã®ãããåææ¡ä»¶ã¯ã\(t=0ãi(0)=0\)ããšãªããŸãã
(25)åŒã«åææ¡ä»¶ãä»£å ¥ãããšã
\begin{eqnarray}
i(0)&=&\displaystyle\frac{E}{R}-e^{-\frac{R}{L}Ã0}Ãe^{D}\\
{\Leftrightarrow}0&=&\displaystyle\frac{E}{R}-e^{0}Ãe^{D}\\
&=&\displaystyle\frac{E}{R}-1Ãe^{D}\\
&=&\displaystyle\frac{E}{R}-e^{D}\tag{26}
\end{eqnarray}
ãšãªããŸãã
ã€ãŸããã\(t=0\)ãã®æãã\(e^{D}=\displaystyle\frac{E}{R}\)ããšãªããŸãããªããç©å宿°\(D\)ãæ±ããŠãè¯ãã§ããã(25)åŒã«ãããŠãã\(e^{D}\)ãããã®ãŸãŸä»£å ¥ã§ããŸãã
ãã®ãããä»åã¯ã\(e^{D}=\displaystyle\frac{E}{R}\)ããŸã§ã®å°åºã§å€§äžå€«ã§ãã
(26)åŒã(25)åŒã«ä»£å ¥ãããšã次åŒãšãªããã³ã³ãã³ãµ\(C\)ã«èããããé»è·\(q(t)\)ãå°åºããããšãã§ããŸããã
\begin{eqnarray}
i(t)&=&\frac{E}{R}-e^{-\frac{R}{L}t}Ãe^{D}\\
&=&\frac{E}{R}-e^{-\frac{R}{L}t}Ã\frac{E}{R}\\
&=&\frac{E}{R}\left(1-e^{-\frac{R}{L}t}\right)\\
&=&\frac{E}{R}-\frac{E}{R}e^{-\frac{R}{L}t}\tag{27}
\end{eqnarray}
ãªãã(27)åŒã®å³èŸºã®ç¬¬1é ã¯å®åžžè§£ã第2é ã¯é枡解ãšåŒã°ããŠããŸãã
è£è¶³
- æå®æ°\({\tau}=\displaystyle\frac{L}{R}\)ã®åäœããªã\({\mathrm{[s]}}\)ãªã®ã
ã€ã³ãã¯ã¿\(L\)ã®åäœã¯ã\(v_{L}(t)=L\displaystyle\frac{di(t)}{dt}{\Leftrightarrow}L=v_{L}(t)Ã\displaystyle\frac{dt}{di(t)}\)ããã
\begin{eqnarray}
ã€ã³ãã¯ã¿Lã®åäœ={{\mathrm{[V]}}}Ã\frac{{\mathrm{[s]}}}{{\mathrm{[A]}}}
\end{eqnarray}
ãšãªããŸãã
æµæ\(R\)ã®åäœã¯ã\(v_{R}(t)=Ri(t){\Leftrightarrow}R=\displaystyle\frac{v_{R}(t)}{i(t)}\)ããã
\begin{eqnarray}
æµæRã®åäœ=\frac{{\mathrm{[V]}}}{{\mathrm{[A]}}}
\end{eqnarray}
ãšãªããŸãã
ãããã£ãŠãæå®æ°\({\tau}=\displaystyle\frac{L}{R}\)ã®åäœã¯
\begin{eqnarray}
æå®æ°{\tau}=\frac{L}{R}ã®åäœ=\frac{{{\mathrm{[V]}}}Ã\displaystyle\frac{{\mathrm{[s]}}}{{\mathrm{[A]}}}}{\displaystyle\frac{{\mathrm{[V]}}}{{\mathrm{[A]}}}}={\mathrm{[s]}}
\end{eqnarray}
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