Theo gia thiet thi khi noi tat tu dong dien trong hai truong hop vuong pha voi nhau nen: $\frac{R}{Z_{L}}=\frac{Z_{C}-Z_{L}}{R}=>Z_{C}-Z_{L}=\frac{R^2}{Z_{L}}$Khi noi tat tu ta cung co dien ap hieu dung giua 2 dau dien tro R tang 2 lan nen: $2\sqrt{R^2+Z^2_{L}}=\sqrt{R^2+(Z_{L}-Z_{C})^2}$ $<=>4R^2+4Z^2_{L}=R^2+\frac{R^4}{Z^2_{L}}$ $<=>R^4-3R^2.Z^2_{L}-4Z^4_{L}=0$ Day la pt dang cap dang co ban de dang suy ra $R=2Z_{L}$Khi do de dang tim dk he so cong suat cua doan mach luc sau $cos\varphi=\frac{R}{\sqrt{R^2+Z^2_{L}}}\frac{R}{\sqrt{R^2+\frac{R^2}{4}}}=\frac{2}{\sqrt{5}}$
Theo gia thiet thi khi noi tat tu dong dien trong hai truong hop vuong pha voi nhau nen: $\frac{R}{Z_{L}}=\frac{Z_{C}-Z_{L}}{R}=>Z_{C}-Z_{L}=\frac{R^2}{Z_{L}}$Khi noi tat tu ta cung co dien ap hieu dung giua 2 dau dien tro R tang 2 lan nen: $2\sqrt{R^2+Z^2_{L}}=\sqrt{R^2+(Z_{L}-Z_{C})^2}$ $<=>4R^2+4Z^2_{L}=R^2+\frac{R^4}{Z^2_{L}}$ $<=>R^4-3R^2.Z^2_{L}-4Z^4_{L}=0$ Day la pt dang cap dang co ban de dang suy ra $R=4Z_{L}$Khi do de dang tim dk he so cong suat cua doan mach luc sau $cos\varphi=\frac{R}{\sqrt{R^2+Z^2_{L}}}\frac{R}{\sqrt{R^2+\frac{R^2}{16}}}=\frac{4}{\sqrt{17}}$
Theo gia thiet thi khi noi tat tu dong dien trong hai truong hop vuong pha voi nhau nen: $\frac{R}{Z_{L}}=\frac{Z_{C}-Z_{L}}{R}=>Z_{C}-Z_{L}=\frac{R^2}{Z_{L}}$Khi noi tat tu ta cung co dien ap hieu dung giua 2 dau dien tro R tang 2 lan nen: $2\sqrt{R^2+Z^2_{L}}=\sqrt{R^2+(Z_{L}-Z_{C})^2}$ $<=>4R^2+4Z^2_{L}=R^2+\frac{R^4}{Z^2_{L}}$ $<=>R^4-3R^2.Z^2_{L}-4Z^4_{L}=0$ Day la pt dang cap dang co ban de dang suy ra $R=
2Z_{L}$Khi do de dang tim dk he so cong suat cua doan mach luc sau $cos\varphi=\frac{R}{\sqrt{R^2+Z^2_{L}}}\frac{R}{\sqrt{R^2+\frac{R^2}{
4}}}=\frac{
2}{\sqrt{
5}}$