é¦å æ¥è¯´è¯´â³U/â³Iæ¯è¡¨ç¤ºä»ä¹ææï¼
第ä¸ç§æ¯é对å®å¼çµé»ï¼
æ¯å¦å°é»å¼ä¸ºRççµé»æ¥å°æçµè·¯ä¸ï¼æµå¾å®ä¸¤ç«¯ççµå为U1ï¼éè¿ççµæµä¸ºI1ãåU1=I1Rï¼è¥å°å®ä¸¤ç«¯ççµåéå°U2ï¼éè¿ççµæµä¸ºI2ï¼åæU2=I2Rï¼
U1-U2=I1R-I2R=Rï¼I1-I2ï¼,åR=(U1-U2)/(I1-I2)=â³U/â³Iï¼å¯ä»¥çåºâ³U/â³Iæ¯è¡¨ç¤ºçæ¯Rçé»å¼ï¼ç±äºâ³Uåâ³Ié½æ¯åéï¼ç´æ¥å¤ææ¯å¼æ¯å¤æä¸äºçï¼ä½åªè¦æç½â³U/â³Içæä¹ï¼å°±å®¹æå¤æäºã
第äºç§æ¯é»å¼åçååçæ åµï¼
å¦æRæ¯åé»å¨ï¼åæ¨ä¸åºä¸è¿°å ³ç³»ï¼å³Råâ â³U/â³Iï¼ä¹å°±æ¯è¯´â³U/â³Içæ¯å¼ä¸æ¯è¡¨ç¤ºRåçé»å¼ï¼è¦å¤ææ¯å¼ç大å°å°±è¦å¦æ³åæ³äºã
ç°å¨æ¥è¯´è¯´æ¬é¢ï¼
Açæ¡ï¼U1/Iåâ³U1/â³Ié½æ¯è¡¨ç¤ºR1çé»å¼ï¼ç±äºR1ä¸åï¼æ以æ¯å¼é½ä¸åãæ£ç¡®
Bçæ¡ï¼U2/I表示çæ¯R2çé»å¼ï¼ç±äºR2å¨å¢å¤§ï¼æ以æ¯å¼ä¹ä¼å¢å¤§ï¼ä½â³U2/â³Iå°±ä¸æ¯æ¯è¡¨ç¤ºR2çé»å¼ï¼ä½ä»ä»£è¡¨çæ¯R1årçæ»çµé»ï¼ç±äºR1+r没æåï¼æ以â³U2/â³Içæ¯å¼åºä¸åï¼æ Béã
Cçæ¡ï¼æ£ç¡®
Dçæ¡ï¼U3/Iæ¯è¡¨ç¤ºçå¤çµè·¯çæ»çµé»ï¼ç±äºè¿ä¸ªå¤çµè·¯çæ»çµé»å¨å¢å¤§ï¼æ以æ¯å¼ä¼å¢å¤§ãä½â³U3/â³Iå°±ä¸æ¯è¡¨ç¤ºå¤çµè·¯çæ»çµé»ï¼èæ¯è¡¨ç¤ºçæ¯å é»ãç±äºå é»ä¸åæ以â³U3/â³Iåºä¸åï¼åºDæ£ç¡®ã