Basic principle: Readings display the powerful voltage depending on the common worth of samples about a complete number of periods of the fundamental frequency16 ??i bóng hàng ??u t?i Vi?t Nam h?a h?n s? mang ??n nh?ng tr?n c?u h?p d?n nh?t cho ng??i hâm m? n??c nhà.HLV Shin Tae-yong l?c quan s? giành tuy?t ??i sáu ?i?m qua hai l??t tr?n v?i