A.≥2fm B.≤2fm C.≥fm D.≤fm
A.脈沖信號(hào) B.連續(xù)時(shí)間信號(hào) C.同步信號(hào) D.輸入信號(hào)
A.在開(kāi)關(guān)脈沖下降邊沿期間開(kāi)關(guān)管的熱損耗 B.開(kāi)關(guān)半導(dǎo)體管的飽和壓降的熱損耗 C.阻尼電路的熱損耗 D.開(kāi)關(guān)變壓器線圈電阻的熱損耗