Question

4(a)(i) Explain a logic truth table. (ii) Name two types of logic gate. (iii) Using the two named logic gates in 4a(ii), complete the truth table in Table 1: X, Y, Z=X OR Y, Z=X AND Y for X,Y = (0,0),(0,1),(1,0),(1,1).
(b) Explain the term comparator as a logic device.

Accepted Answer

(a)(i) A logic truth table is a mathematical table used to evaluate the truth value of logical statements or arguments; it displays logical operations on input signals in table format.

(ii) Types of logic gate: OR gate, AND gate (also acceptable: NOT, NOR, NAND, XOR, EXNOR gates).

(iii) Truth table -- X=0,Y=0: Z(OR)=0, Z(AND)=0. X=0,Y=1: Z(OR)=1, Z(AND)=0. X=1,Y=0: Z(OR)=1, Z(AND)=0. X=1,Y=1: Z(OR)=1, Z(AND)=1.

(b) A comparator is a logic device that compares two input values (X and Y) and produces an output based on their relative values -- a digital circuit that determines whether one value is greater than, less than or equal to another. The output is 1 if the condition is met and 0 if not. Comparators are commonly used in digital systems for data comparison, error detection, sorting and searching, digital arithmetic circuits, etc.

WAEC Computer Studies 2024 Theory — Question 4

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