3-5
Figure 3-5. —Exclusive NOR gate timing diagram.
Q1. What is the sign of operation for the X-OR gate?
Q2. What will be the output of an X-OR gate when both inputs are HIGH?
Q3. A two-input X-OR gate will produce a HIGH output when the inputs are at what logic levels?
Q4. What type of gate is represented by the output Boolean expression
R
T
?
Q5. What will be the output of an X-NOR gate when both inputs are LOW?
ADDERS
Adders are combinations of logic gates that combine binary values to obtain a sum. They are
classified according to their ability to accept and combine the digits. In this section we will discuss
quarter adders, half adders, and full adders.
QUARTER ADDER
A quarter adder is a circuit that can add two binary digits but will not produce a carry. This circuit
will produce the following results:
0 plus 0 = 0
0 plus 1 = 1
1 plus 0 = 1
1 plus 1 = 0 (no carry)
