Chapter 36: Combinational Logic Circuits
MULTIPLE CHOICE
1. A(n) ____ is a combinational logic circuit that accepts one or more inputs and generates a multibit
binary output.
a.
decoder
c.
multiplexer
b.
encoder
d.
comparator
2. The function of the ____ encoder is to take a single digit (0 to 9) as input and to output a 4-bit code
representation of the digit.
a.
decimal-to-binary
c.
1-of-8
b.
decimal-to-binary priority
d.
1-of-16
3. If two keys are pressed simultaneously the ____ encoder produces a BCD output corresponding to the
highest-order decimal digit appearing on the input.
a.
decimal-to-binary
c.
1-of-8
b.
decimal-to-binary priority
d.
1-of-16
4. A(n) ____ processes a complex binary code into a recognizable digit or character.
a.
multiplexer
c.
adder
b.
encoder
d.
decoder
5. A(n) ____ is a circuit used to select and route any one of several input signals to a single output.
a.
encoder
c.
multiplexer
b.
decoder
d.
comparator
6. In addition to data line selection, a common application of a(n) ____ is parallel-to-serial data
conversion.
a.
encoder
c.
multiplexer
b.
adder
d.
comparator
7. A(n) ____ is the primary computation unit in a digital computer.
a.
adder
c.
comparator
b.
subtractor
d.
multiplexer
8. The truth table for a(n) ____ gate and an XOR gate is the same as the truth table developed using the
binary addition rules.
a.
OR
c.
NOT
b.
AND
d.
XNOR
9. A(n) ____ is a circuit used simply to determine if two numbers are equal.
a.
multiplexer
c.
subtractor
b.
adder
d.
comparator
10. The truth table for the subtracting rules of binary numbers is equivalent to the truth table for a(n) ____
gate with an inverter on one of the inputs and an XOR gate.
a.
AND
c.
NOT
b.
OR
d.
XNOR
COMPLETION
1. ____________________ logic circuits are circuits that combine the basic components of AND gates,
OR gates, and inverters to produce more sophisticated circuits.
2. For analog applications, multiplexers are built of ____________________ and transistor switches.
3. A(n) ____________________ subtractor does not have a borrow input.
SHORT ANSWER
1. Describe the BCD–to-seven-segment decoder and its display.
2. Describe how the PLA is different from the PAL.
