15. (R+E+S) HI+P

18.

16a. C+R+A

from a logic diagram to an output Boolean expression can best be

b. (C+R+A) Z

gained through practice. All problems should be solved

c. (C+R+A) Z+Y

systematically to develop the efficiency required of a technician.

17. (D+A) Y+Z+E

The diagram above is an example of a fourth-order-logic diagram

consisting of two AND gates and two OR gates. The logic diagram

is converted to an output Boolean expression by starting at the

inputs, using the step-by-step procedure, and working toward the

final output.

same manner as normal algebra to maintain proper

identity and separation of quantities. The quantity

(A+B+C) above is ANDed with D and must be shown with

parentheses. The quantity [(A+B+C) D+E] is ANDed with

FG and must be shown with brackets. If parentheses

were used again, the quantity ((A+B+C) D+E) would be

confusing.