Question 1

Which of the following is correct for a gated D latch?

Accepted Answer

A)  The output toggles if one of the inputs is held high. 
B)  Only one of the inputs can be high at a time. 
C)  Q output follows the input D when the ENABLE is high. 
D)  The output complement follows the input when enabled. 
A)  The output toggles if one of the inputs is held high. 
B)  Only one of the inputs can be high at a time. 
C)  Q output follows the input D when the ENABLE is high. 
D)  The output complement follows the input when enabled. C

Question 2

The symbol for an edge- triggered flip- flop has a triangle on its clock input.

Accepted Answer

A) True 
 B)False  True

Question 3

These waveforms are applied to a gated D latch, which is initially RESET. Which of the areas identified on the Q waveform is incorrect?

Accepted Answer

A)  Area a 
B)  Area b 
C)  Area c 
D)  Area d 
A)  Area a 
B)  Area b 
C)  Area c 
D)  Area d C

Question 4

The asynchronous inputs to a flip- flop are normally labeled_____and________ , and are normally active_______inputs.

Accepted Answer

A)  START, STOP, low 
B)  SET, RESET, high 
C)  PRE, CLR, low 
D)  ON, OFF, high 
A)  START, STOP, low 
B)  SET, RESET, high 
C)  PRE, CLR, low 
D)  ON, OFF, high

Question 5

A push- button switch is used to input data to a register. The output of the register is erratic. Which of the following could be the cause of the problem?

Accepted Answer

A)  The power supply is probably noisy. 
B)  The socket contacts on the register IC are corroded. 
C)  The switch contacts are bouncing. 
D)  The register IC is intermittent and failure is imminent. 
A)  The power supply is probably noisy. 
B)  The socket contacts on the register IC are corroded. 
C)  The switch contacts are bouncing. 
D)  The register IC is intermittent and failure is imminent.

Question 6

An astable multivibrator is a circuit that _________.

Accepted Answer

A)  has two stable states 
B)  has one stable state 
C)  produces a continuous output signal 
D)  Both B and C are correct. 
A)  has two stable states 
B)  has one stable state 
C)  produces a continuous output signal 
D)  Both B and C are correct.

Question 7

The ON time of a 555 monostable multivibrator is determined by tw = 1.1RC.

Accepted Answer

A) True 
 B)False

Question 8

When both inputs of a J- K pulse- triggered FF are high, and the clock cycles, the output wil_________

Accepted Answer

A)  remain unchanged 
B)  be invalid 
C)  toggle 
D)  not change 
A)  remain unchanged 
B)  be invalid 
C)  toggle 
D)  not change

Question 9

All multivibrators require feedback.

Accepted Answer

A) True 
 B)False

Question 10

The L in 74L71 stands for _______.

Accepted Answer

A)  low power 
B)  the type of package 
C)  lock- out flip- flop 
D)  low frequency 
A)  low power 
B)  the type of package 
C)  lock- out flip- flop 
D)  low frequency

Question 11

An active- HIGH input S- R latch has a 1 on the S input and a 0 on the R input. What state is the latch in?

Accepted Answer

A)  Q = 0,   = 1 
B)  Q = 1,   = 0 
C)  Q = 1,   = 1 
D)  Q = 0,   = 0 
A)  Q = 0,   = 1 
B)  Q = 1,   = 0 
C)  Q = 1,   = 1 
D)  Q = 0,   = 0

Question 12

A diode can be added to the discharge path for a 555 astable multivibrator to obtain duty cycles that are less than 50%.

Accepted Answer

A) True 
 B)False

Question 13

What primary advantage does the J- K flip- flop have over the S- R flip- flop?

Accepted Answer

A)  The J- K flip- flop does not have propagation delay problems. 
B)  The J- K flip- flop does not have an invalid input state. 
C)  The J- K flip- flop is much faster. 
D)  The J- K flip- flop only needs one output. 
A)  The J- K flip- flop does not have propagation delay problems. 
B)  The J- K flip- flop does not have an invalid input state. 
C)  The J- K flip- flop is much faster. 
D)  The J- K flip- flop only needs one output.

Question 14

What symbol is used to identify edge- triggered flip- flops?

Accepted Answer

A)  An inverted "L" on the output 
B)  The letter E on the Enable input 
C)  A triangle on the Clock input 
D)  A bubble on the Clock input 
A)  An inverted "L" on the output 
B)  The letter E on the Enable input 
C)  A triangle on the Clock input 
D)  A bubble on the Clock input

Question 15

A positive edge- triggered J- K flip- flop is used to produce a two- phase clock. However, when the circuit is operated it produces erratic results. Close examination with an oscilloscope reveals the presence of glitches. What might be the source of these glitches?

Accepted Answer

A)  A race condition exists between the J and K inputs. 
B)  The PRESET and CLEAR terminals may have been left floating. 
C)  A race condition exists between the Q and Q outputs to the AND gate. 
D)  A race condition exists between the CLOCK and the outputs of the flip- flop feeding the AND gate. 
A)  A race condition exists between the J and K inputs. 
B)  The PRESET and CLEAR terminals may have been left floating. 
C)  A race condition exists between the Q and Q outputs to the AND gate. 
D)  A race condition exists between the CLOCK and the outputs of the flip- flop feeding the AND gate.

Question 16

All multivibrators are level triggered.

Accepted Answer

A) True 
 B)False

Question 17

How is the invalid input state problem associated with the S- R flip- flop overcome?

Accepted Answer

A)  The R terminal is eliminated. 
B)  A single input terminal is used (
D) . 
C)  The R input is fed through an inverter. 
D)  Both B and C are correct. 
A)  The R terminal is eliminated. 
B)  A single input terminal is used (
D) . 
C)  The R input is fed through an inverter. 
D)  Both B and C are correct.

Question 18

A J- K flip- flop is being used as a divide- by- 2 circuit when _________.

Accepted Answer

A)  the J and K inputs are tied to Vcc 
B)  the reset is tied to the clock 
C)  the J and K inputs are tied to ground 
D)  all the inputs are connected to the preset 
A)  the J and K inputs are tied to Vcc 
B)  the reset is tied to the clock 
C)  the J and K inputs are tied to ground 
D)  all the inputs are connected to the preset

Question 19

A one- shot is a multivibrator that must be triggered to produce each output pulse.

Accepted Answer

A) True 
 B)False

Question 20

The J- K flip- flop toggles when both inputs are high during the transition of the clock signal.

Accepted Answer

A) True 
 B)False

Which of the following is correct for a gated D latch?

The symbol for an edge- triggered flip- flop has a triangle on its clock input.

These waveforms are applied to a gated D latch, which is initially RESET. Which of the areas identified on the Q waveform is incorrect?

The asynchronous inputs to a flip- flop are normally labeled_and , and are normally active___inputs.

A push- button switch is used to input data to a register. The output of the register is erratic. Which of the following could be the cause of the problem?

An astable multivibrator is a circuit that _________.

The ON time of a 555 monostable multivibrator is determined by t_w= 1.1RC.

When both inputs of a J- K pulse- triggered FF are high, and the clock cycles, the output wil_________

All multivibrators require feedback.

The L in 74L71 stands for _______.

An active- HIGH input S- R latch has a 1 on the S input and a 0 on the R input. What state is the latch in?

A diode can be added to the discharge path for a 555 astable multivibrator to obtain duty cycles that are less than 50%.

What primary advantage does the J- K flip- flop have over the S- R flip- flop?

What symbol is used to identify edge- triggered flip- flops?

A positive edge- triggered J- K flip- flop is used to produce a two- phase clock. However, when the circuit is operated it produces erratic results. Close examination with an oscilloscope reveals the presence of glitches. What might be the source of these glitches?

All multivibrators are level triggered.

How is the invalid input state problem associated with the S- R flip- flop overcome?

A J- K flip- flop is being used as a divide- by- 2 circuit when _________.

A one- shot is a multivibrator that must be triggered to produce each output pulse.

The J- K flip- flop toggles when both inputs are high during the transition of the clock signal.

Introductory Concepts

Number Systems, Operations, and Codes

Logic Gates

Boolean Algebra and Logic Simplification

Combinational Logic Analysis

Functions of Combinational Logic

Shift Registers

Counters

Programmable Logic

Data Storage

Signal Conversion and Processing

Data Transmission

Data Processing and Control

Integrated Circuit Technologies

Filters

Exam 7: Latches, Flip-Flops, and Timers

Which of the following is correct for a gated D latch?

The symbol for an edge- triggered flip- flop has a triangle on its clock input.

These waveforms are applied to a gated D latch, which is initially RESET. Which of the areas identified on the Q waveform is incorrect?

The asynchronous inputs to a flip- flop are normally labeled_____and________ , and are normally active_______inputs.

A push- button switch is used to input data to a register. The output of the register is erratic. Which of the following could be the cause of the problem?

An astable multivibrator is a circuit that _________.

The ON time of a 555 monostable multivibrator is determined by tw = 1.1RC.

When both inputs of a J- K pulse- triggered FF are high, and the clock cycles, the output wil_________

All multivibrators require feedback.

The L in 74L71 stands for _______.

An active- HIGH input S- R latch has a 1 on the S input and a 0 on the R input. What state is the latch in?

A diode can be added to the discharge path for a 555 astable multivibrator to obtain duty cycles that are less than 50%.

What primary advantage does the J- K flip- flop have over the S- R flip- flop?

What symbol is used to identify edge- triggered flip- flops?

A positive edge- triggered J- K flip- flop is used to produce a two- phase clock. However, when the circuit is operated it produces erratic results. Close examination with an oscilloscope reveals the presence of glitches. What might be the source of these glitches?

All multivibrators are level triggered.

How is the invalid input state problem associated with the S- R flip- flop overcome?

A J- K flip- flop is being used as a divide- by- 2 circuit when _________.

A one- shot is a multivibrator that must be triggered to produce each output pulse.

The J- K flip- flop toggles when both inputs are high during the transition of the clock signal.

Introductory Concepts

Number Systems, Operations, and Codes

Logic Gates

Boolean Algebra and Logic Simplification

Combinational Logic Analysis

Functions of Combinational Logic

Shift Registers

Counters

Programmable Logic

Data Storage

Signal Conversion and Processing

Data Transmission

Data Processing and Control

Integrated Circuit Technologies

Filters

The asynchronous inputs to a flip- flop are normally labeled_and , and are normally active___inputs.

The ON time of a 555 monostable multivibrator is determined by t_w= 1.1RC.