Cho mach dien xoay chieu RLC mac noi tiep, cuon day thuan camdo tu cam L, dien dung
C thoa dieu kien R L
C
= , dat vao hai dau doan mach mot hieu dien the xoay chieu on dinh, tan so thay doi, khi tan so goc cua dong dien la ω1va ω2 =4ω1 thi mach dien co cung he so cong suat, he so cong suat cua doan mach la:
A 3
3
12 C
5
12 D
2 13