i = V R 2 + R 1 {\displaystyle i={\frac {V}{R_{2}+R_{1}}}} V o = i R 2 = R i v i R 2 + R 1 {\displaystyle V_{o}=iR_{2}=R_{i}{\frac {v_{i}}{R_{2}+R_{1}}}} V o V i = R 2 R 2 + R 1 {\displaystyle {\frac {V_{o}}{V_{i}}}={\frac {R_{2}}{R_{2}+R_{1}}}} V o V i = R 2 R 2 + R 1 {\displaystyle {\frac {V_{o}}{V_{i}}}={\frac {R_{2}}{R_{2}+R_{1}}}}
V = V 2 R 1 R 1 + R 3 = V 1 R 1 R 2 + R 1 {\displaystyle V=V_{2}{\frac {R_{1}}{R_{1}+R_{3}}}=V_{1}{\frac {R_{1}}{R_{2}+R_{1}}}} V 2 V 1 = R 1 + R 3 R 1 R 1 R 2 + R 3 {\displaystyle {\frac {V_{2}}{V_{1}}}={\frac {R_{1}+R_{3}}{R_{1}}}{\frac {R_{1}}{R_{2}+R_{3}}}} V 2 V 1 = R 1 + R 3 R 2 + R 3 {\displaystyle {\frac {V_{2}}{V_{1}}}={\frac {R_{1}+R_{3}}{R_{2}+R_{3}}}}
i 1 = i 2 + i 3 {\displaystyle i_{1}=i_{2}+i_{3}} v i R 1 = v i − v o R 2 + v o R 3 {\displaystyle {\frac {v_{i}}{R_{1}}}={\frac {v_{i}-v_{o}}{R_{2}}}+{\frac {v_{o}}{R_{3}}}} v i v o = ( R 3 R 1 ) ( R 2 − R 1 R 2 − R 3 ) {\displaystyle {\frac {v_{i}}{v_{o}}}=({\frac {R_{3}}{R_{1}}})({\frac {R_{2}-R_{1}}{R_{2}-R_{3}}})} v o v i = ( R 3 R 1 ) ( R 2 − R 1 R 2 − R 3 ) {\displaystyle {\frac {v_{o}}{v_{i}}}=({\frac {R_{3}}{R_{1}}})({\frac {R_{2}-R_{1}}{R_{2}-R_{3}}})}
R E Q = ( R 1 ‖ R 2 ) + R 3 {\displaystyle R_{EQ}=(R_{1}\|R_{2})+R_{3}} R E Q = R 1 R 2 R 1 + R 2 + R 3 {\displaystyle R_{EQ}={R_{1}R_{2} \over R_{1}+R_{2}}+R_{3}}
Δ - Y Hoán Chuyển R 1 = R a R b R a + R b + R c {\displaystyle R_{1}={\frac {R_{\mathrm {a} }R_{\mathrm {b} }}{R_{\mathrm {a} }+R_{\mathrm {b} }+R_{\mathrm {c} }}}} R 2 = R b R c R a + R b + R c {\displaystyle R_{2}={\frac {R_{\mathrm {b} }R_{\mathrm {c} }}{R_{\mathrm {a} }+R_{\mathrm {b} }+R_{\mathrm {c} }}}} R 3 = R c R a R a + R b + R c {\displaystyle R_{3}={\frac {R_{\mathrm {c} }R_{\mathrm {a} }}{R_{\mathrm {a} }+R_{\mathrm {b} }+R_{\mathrm {c} }}}} Y - Δ Hoán Chuyển R a = R 1 R 2 + R 2 R 3 + R 3 R 1 R 2 {\displaystyle R_{\mathrm {a} }={\frac {R_{1}R_{2}+R_{2}R_{3}+R_{3}R_{1}}{R_{2}}}} R b = R 1 R 2 + R 2 R 3 + R 3 R 1 R 3 {\displaystyle R_{\mathrm {b} }={\frac {R_{1}R_{2}+R_{2}R_{3}+R_{3}R_{1}}{R_{3}}}} R c = R 1 R 2 + R 2 R 3 + R 3 R 1 R 1 {\displaystyle R_{\mathrm {c} }={\frac {R_{1}R_{2}+R_{2}R_{3}+R_{3}R_{1}}{R_{1}}}}