單項(xiàng)選擇題
用與非門設(shè)計(jì)一個1位數(shù)值范圍判別電路。十進(jìn)制數(shù)用8421BCD碼表示。當(dāng)輸入的十進(jìn)制數(shù)大于等于5時,電路輸出為1,當(dāng)輸入的十進(jìn)制數(shù)小于等于4時,輸出為0。列出真值表為( )
A、A B C D Y 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 1 1 0 0 1 0 0 0 0 1 0 1 1 0 1 1 0 1 0 1 1 1 1 1 0 0 0 1 1 0 0 1 1
B、A B C D Y 0 0 0 0 1 0 0 0 1 1 0 0 1 0 1 0 0 1 1 1 0 1 0 0 1 0 1 0 1 0 0 1 1 0 0 0 1 1 1 0 1 0 0 0 0 1 0 0 1 0
C、A B C D Y 0 0 0 0 1 0 0 0 1 1 0 0 1 0 1 0 0 1 1 0 0 1 0 0 1 0 1 0 1 0 0 1 1 0 0 0 1 1 1 0 1 0 0 0 0 1 0 0 1 0
D、A B C D Y 0 0 0 0 1 0 0 0 1 1 0 0 1 0 1 0 0 1 1 1 0 1 0 0 1 0 1 0 1 1 0 1 1 0 1 0 1 1 1 0 1 0 0 0 0 1 0 0 1 0