# Combinational Logic Circuits MCQs

## A basic multiplexer principle can be demonstrated through the use of a:

• A. single-pole relay
• B. DPDT switch
• C. rotary switch
• D. linear stepper

## A circuit that responds to a specific set of signals to produce a related digital signal output is called a(n):

• A. BCD matrix
• B. display driver
• C. encoder
• D. decoder

## A code in which each individual digit of a decimal number is represented by a 4-bit binary number is _________.

• A. binary coded decimal
• B. binary
• D. seven-segment code

## A device that uses a binary decoder to direct a digital signal from a single source to one of several destinations is a ________.

• A. multiplexer
• B. demultiplexer
• C. encoder
• D. comparator

## A multiplexed display:

• A. accepts data inputs from one line and passes this data to multiple output lines
• B. uses one display to present two or more pieces of information
• C. accepts data inputs from multiple lines and passes this data to multiple output lines
• D. accepts data inputs from several lines and multiplexes this input data to four BCD lines

## A technique that can be used in multiple-digit numerical displays to control suppression or display of leading or trailing zeros in the display is called _________.

• B. time division multiplexing
• C. parity generation
• D. ripple blanking

• A. 4
• B. 8
• C. 10
• D. 1

## In a BCD-to-seven-segment converter, why must a code converter be utilized?

• A. No conversion is necessary.
• B. to convert the 4-bit BCD into gray code
• C. to convert the 4-bit BCD into 10-bit code
• D. to convert the 4-bit BCD into 7-bit code

## Most demultiplexers facilitate which of the following?

• B. single input, multiple outputs
• C. ac to dc
• D. odd parity to even parity

## One application of a digital multiplexer is to facilitate:

• A. code conversion
• B. parity checking
• C. parallel-to-serial data conversion
• D. data generation

## Parity systems are defined as either_____ or _____ and will add an extra _____ to the digital information being transmitted.

• A. positive, negative, byte
• B. odd, even, bit
• C. upper, lower, digit
• D. on, off, decimal

## Select one of the following statements that best describes the parity method of error detection:

• A. Parity checking is best suited for detecting single-bit errors in transmitted codes.
• B. Parity checking is best suited for detecting double-bit errors that occur during the transmission of codes from one location to another.
• C. Parity checking is not suitable for detecting single-bit errors in transmitted codes.
• D. Parity checking is capable of detecting and correcting errors in transmitted codes.

## The diodes in a seven-segment display where all cathodes are tied together and grounded are illuminated when a logic ____________________ is applied to the ____________________.

• A. LOW, anodes
• B. LOW, count down control line
• C. HIGH, anode
• D. HIGH, count up control line

## When two or more inputs are active simultaneously, the process is called:

• A. first-in, first-out processing
• B. priority encoding
• C. ripple blanking
• D. priority decoding

• A. encoder
• B. display
• C. counter
• D. decoder