I placed a one (1) everywhere a term of the sum of products expression would evaluate as true. Since in a sum or products expression, each term is joined with an "or" (denoted by the + between the terms), the expression (Y) will evaluate as true any time one of the terms is true. The expression for (Y) has six terms, so there will be six rows with a one (1) in the column for Y. The third term in the expression is notA and notB and notC and D. So I am looking for 0001. (notVariable = 0, Variable = 1) This means there is a zero (0) in the columns for A, B, and C. It also means there is an one (1) in the column for D. You can see that is where I placed the first 1 in (Y) in the video.
The C column is just part of the "counting" in the truth table. The first line of the inputs in a truth table is 0, then 1, then 2, and so on. How high you go is determined by how many inputs there are. If you have 1 input, you need to have two lines: 0 and 1. If you have 2 inputs, you need 4 lines: 0, 1, 2, 3. If you have 3 inputs you need 8 lines: 0-7. 000 = 0 001 =1 010 = 2 011 = 3 100 = 4 101 = 5 110 = 6 111 = 7 The value for C is the middle number in the above combinations.
after 4 years in college, I took digital system twice, I never understood this topic until now. thank you very much... you just rock my world and because of you, im super ready for my electrical FE exam. thank you...
I've almost been stuidying this for 5h in class ig and didn't understand anything and you are poping from nowhere explaining this better than my professor in 5min lol ( my professor is the director of a laboratory in France :/ )
