MSI Logic Circuits MCQs

Question 1

Which statement below best describes the function of a decoder?

Accepted Answer

A decoder will convert a binary number into a specific output representing a particular character or digit.

Answer

A decoder will convert a decimal number into the proper binary equivalent.

Answer

Decoders are used to prevent improper operation of digital systems.

Answer

Decoders are special ICs that are used to make it possible for one brand of computer to talk to another.

Question 2

One can safely state that the output lines for a demultiplexer are under the direct control of the:

Accepted Answer

input data select lines.

Answer

the internal AND gates.

Answer

the internal OR gate.

Answer

Input data line.

Question 3

A 16-input multiplexer is to be used to perform parallel-to-serial data conversion. Which of the following counters would be required to provide the data select inputs?

Accepted Answer

MOD 16

Answer

MOD 8

Answer

MOD 4

Answer

MOD 2

Question 4

A breadboard-circuit design using a BCD-to-decimal decoder has a problem wherein the operation of the system is erratic. The technician uses his scope to examine the waveforms throughout the system and doesn't really see any problems. While he's scratching his head, what helpful advice can you offer him as to what might be wrong and what to do to correct the problem?

Accepted Answer

Glitches are probably the culprit; strobe the decoder.

Answer

The decoder is thermally intermittent; replace it.

Answer

There is probably a bad connection on the wire wrap protoboard; recheck the wiring.

Answer

The decoder is thermally intermittent and must be replaced; or there is probably a bad connection on the wire wrap protoboard, and the wiring must be rechecked.

Question 5

How is the number one (1) indicated on the outputs of a 7447 BCD-to-seven-segment code converter?

Accepted Answer

Segments b and c are active.

Answer

Segment a is active.

Answer

Segment b is active.

Answer

Segments a and b are active.

Question 6

The IEEE/ANSI symbol for a decoder has the internal designation bcd/dec. This means the decoder is a:

Accepted Answer

BCD-to-decimal decoder with four inputs and ten outputs.

Answer

decimal-to-BCD decoder with ten inputs and four outputs.

Answer

BCD-to-decimal decoder with ten inputs and four outputs.

Answer

decimal-to-BCD decoder with four inputs and ten outputs.

Question 7

Multiplexing of digital signals is usually required when:

Accepted Answer

moving data over long distance transmission lines.

Answer

moving data internally within a microprocessor.

Answer

moving data between memory and storage registers in a microprocessor.

Answer

moving data internally within a microprocessor or between memory and storage registers.

Question 8

Which is the decimal number for the BCD number, 10110110?

Accepted Answer

10110110 is not a valid BCD number.

Answer

182

Answer

36

Answer

116

Question 9

In an AHDL BCD to binary code converter, how is multiplication by 10 accomplished?

Accepted Answer

By using the shifting of bits

Answer

By using the library multiplication function

Answer

By using integer types

Answer

By using the multiplication operator