As modules , they are black boxes , in the sense that they will perform desired functions when voltage levels , corresponding to logic states , are presented at the inputs 作為“模塊” ,它們是一些黑色的盒子。當(dāng)通電時(shí),它們就能以這種形式工作,對(duì)邏輯信號(hào)進(jìn)行處理,并輸出結(jié)果。