Step1：写出函数Y的逻辑表达式

Y 1 = A B C ‾ Y_{1} = \overline{ABC} Y1​=ABC Y 2 = A ⋅ Y 1 = A ⋅ A B C ‾ Y_2 = A·Y_{1} = A·\overline{ABC} Y2​=A⋅Y1​=A⋅ABC Y 3 = B ⋅ Y 1 = B ⋅ A B C ‾ Y_3 = B·Y_{1}= B·\overline{ABC} Y3​=B⋅Y1​=B⋅ABC Y 4 = C ⋅ Y 1 = C ⋅ A B C ‾ Y_4 = C·Y_{1}= C·\overline{ABC} Y4​=C⋅Y1​=C⋅ABC

Y = Y 2 + Y 3 + Y 4 ‾ Y = \overline{Y_{2} + Y_{3} + Y_{4}} Y=Y2​+Y3​+Y4​​

Step2：化简（最简与或表达式）

Y = Y 2 + Y 3 + Y 4 ‾ Y = \overline{Y_{2} + Y_{3} + Y_{4}} Y=Y2​+Y3​+Y4​​

= A ⋅ A B C ‾ + B ⋅ A B C ‾ + C ⋅ A B C ‾ ‾ \overline{A·\overline{ABC} + B·\overline{ABC} + C·\overline{ABC}} A⋅ABC+B⋅ABC+C⋅ABC​

= A B C ‾ ⋅ ( A + B + C ) ‾ \overline{\overline{ABC} ·(A+B+C)} ABC⋅(A+B+C)​

= A B C + ( A + B + C ) {ABC} + (A+B+C) ABC+(A+B+C) = A B C + A ‾ ⋅ B ‾ ⋅ C ‾ {ABC} + \overline{A}·\overline{B}· \overline{C} ABC+A⋅B⋅C

Step3：列真值表

Step4：分析逻辑功能

当 A、B、C三个输入变量取值一致时，输出 Y = 1 Y = 1 Y=1 ，否则为0，是“一致判断电路”