Digital Logic

Key Topic 33:  Types of Logic

3-33E1 What is the voltage range considered to be valid logic low input in a TTL device operating at 5 volts?

A. 2.0 to 5.5 volts.

B. -2.0 to -5.5 volts.

C. Zero to 0.8 volts.

D. 5.2 to 34.8 volts.

C. Zero to 0.8 volts.

Digital Logic

Key Topic 33: Types of Logic

3-33E2 What is the voltage range considered to be a valid logic high input in a TTL device operating at 5.0 volts?

A. 2.0 to 5.5 volts.

B. 1.5 to 3.0 volts.

C. 1.0 to 1.5 volts.

D. 5.2 to 34.8 volts.

A. 2.0 to 5.5 volts.

Digital Logic

Key Topic 33: Types of Logic

3-33E3 What is the common power supply voltage for TTL series integrated circuits?

A. 12 volts.

B. 13.6 volts.

C. 1 volt.

D. 5 volts.

Digital Logic

Key Topic 33: Types of Logic

3-33E4 TTL inputs left open develop what logic state?

A. A high-logic state.

B. A low-logic state.

C. Open inputs on a TTL device are ignored.

D. Random high- and low-logic states.

A. A high-logic state.

Digital Logic

Key Topic 33: Types of Logic

3-33E5 Which of the following instruments would be best for checking a TTL logic circuit?

A. VOM.

B. DMM.

C. Continuity tester.

D. Logic probe.

Digital Logic

Key Topic 33: Types of Logic

3-33E6 What do the initials TTL stand for?

A. Resistor-transistor logic.

B. Transistor-transistor logic.

C. Diode-transistor logic.

D. Emitter-coupled logic.

B. Transistor-transistor logic.

Digital Logic

Key Topic 34:  Logic Gates

3-34E1 What is a characteristic of an AND gate?

A. Produces a logic “0” at its output only if all inputs are logic “1”.

B. Produces a logic “1” at its output only if all inputs are logic “1”.

C. Produces a logic “1” at its output if only one input is a logic “1”.

D. Produces a logic “1” at its output if all inputs are logic “0”.

B. Produces a logic “1” at its output only if all inputs are logic “1”.

Digital Logic

Key Topic 34: Logic Gates

3-34E2 What is a characteristic of a NAND gate?

A. Produces a logic “0” at its output only when all inputs are logic “0”.

B. Produces a logic “1” at its output only when all inputs are logic “1”.

C. Produces a logic “0” at its output if some but not all of its inputs are logic “1”.

D. Produces a logic “0” at its output only when all inputs are logic “1”.

Digital Logic

Key Topic 34: Logic Gates

3-34E3 What is a characteristic of an OR gate?

A. Produces a logic “1” at its output if any input is logic “1”.

B. Produces a logic “0” at its output if any input is logic “1”.

C. Produces a logic “0” at its output if all inputs are logic “1”.

D. Produces a logic “1” at its output if all inputs are logic “0”.

A. Produces a logic “1” at its output if any input is logic “1”.

Digital Logic

Key Topic 34: Logic Gates

3-34E4 What is a characteristic of a NOR gate?

A. Produces a logic “0” at its output only if all inputs are logic “0”.

B. Produces a logic “1” at its output only if all inputs are logic “1”.

C. Produces a logic “0” at its output if any or all inputs are logic “1”.

D. Produces a logic “1” at its output if some but not all of its inputs are logic “1”.

C. Produces a logic “0” at its output if any or all inputs are logic “1”. 

Digital Logic

Key Topic 34: Logic Gates

3-34E5 What is a characteristic of a NOT gate?

A. Does not allow data transmission when its input is high.

B. Produces a logic “0” at its output when the input is logic “1” and vice versa.

C. Allows data transmission only when its input is high.

D. Produces a logic "1" at its output when the input is logic "1" and vice versa.

Digital Logic

Key Topic 34: Logic Gates

3-34E6 Which of the following logic gates will provide an active high out when both inputs are active high?

A. NAND.

B. NOR.

C. AND.

D. XOR.

C. AND.

Digital Logic

Key Topic 35:  Logic Levels

3-35E1 In a negative-logic circuit, what level is used to represent a logic 0?

A. Low level. 

B. Positive-transition level.

C. Negative-transition level.

D. High level.

Digital Logic

Key Topic 35: Logic Levels

3-35E2 For the logic input levels shown in Figure 3E12, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.)

[image]

A. A is high, B is low and C is low.

B. A is low, B is high and C is high.

C. A is high, B is high and C is low.

D. A is low, B is high and C is low.

B. A is low, B is high and C is high.

Digital Logic

Key Topic 35: Logic Levels

3-35E3 For the logic input levels given in Figure 3E13, what are the logic levels of test points A, B and C in this circuit? (Assume positive logic.)

[image]

A. A is low, B is low and C is high.

B. A is low, B is high and C is low.

C. A is high, B is high and C is high.

D. A is high, B is low and C is low.

C. A is high, B is high and C is high.

Digital Logic

Key Topic 35: Logic Levels

3-35E4 In a positive-logic circuit, what level is used to represent a logic 1?

A. High level

B. Low level

C. Positive-transition level

D. Negative-transition level

A. High level

Digital Logic

Key Topic 35: Logic Levels

3-35E5 Given the input levels shown in Figure 3E14 and assuming positive logic devices, what would the output be?

[image]

A. A is low, B is high and C is high. 

B. A is high, B is high and C is low.

C. A is low, B is low and C is high.

D. None of the above are correct.

A. A is low, B is high and C is high. 

Digital Logic

Key Topic 35: Logic Levels

3-35E6 What is a truth table?

A. A list of input combinations and their corresponding outputs that characterizes a digital device’s function.

B. A table of logic symbols that indicate the high logic states of an op-amp.

C. A diagram showing logic states when the digital device’s output is true.

D. A table of logic symbols that indicates the low logic states of an op-amp.

Digital Logic

Key Topic 36:  Flip-Flops

3-36E1 A flip-flop circuit is a binary logic element with how many stable states?

A. 1

B. 2

C. 4

D. 8

B. 2

 Digital Logic

Key Topic 36: Flip-Flops

3-36E2 What is a flip-flop circuit? A binary sequential logic element with ___stable states.

A. 1

B. 4

C. 2

D. 8

C. 2

 Digital Logic

 Key Topic 36: Flip-Flops

3-36E3 How many flip-flops are required to divide a signal frequency by 4?

A. 1

B. 4

C. 8

D. 2

Digital Logic

 Key Topic 36: Flip-Flops

3-36E4 How many bits of information can be stored in a single flip-flop circuit?

A. 1

B. 2

C. 3

D. 4

A. 1

Digital Logic

Key Topic 36: Flip-Flops

3-36E5 How many R-S flip-flops would be required to construct an 8 bit storage register?

A. 2

B. 4

C. 8

D. 16

C. 8

Digital Logic

Key Topic 36: Flip-Flops

3-36E6 An R-S flip-flop is capable of doing all of the following except:

A. Accept data input into R-S inputs with CLK initiated.

B. Accept data input into PRE and CLR inputs without CLK being initiated.

C. Refuse to accept synchronous data if asynchronous data is being input at same time.

D. Operate in toggle mode with R-S inputs held constant and CLK initiated.

Digital Logic

Key Topic 37:  Multivibrators

3-37E1 The frequency of an AC signal can be divided electronically by what type of digital circuit?

A. Free-running multivibrator.

B. Bistable multivibrator.

C. OR gate.

D. Astable multivibrator.

B. Bistable multivibrator.

Digital Logic

Key Topic 37: Multivibrators

3-37E2 What is an astable multivibrator?

A. A circuit that alternates between two stable states.

B. A circuit that alternates between a stable state and an unstable state.

C. A circuit set to block either a 0 pulse or a 1 pulse and pass the other.

D. A circuit that alternates between two unstable states.

Digital Logic

Key Topic 37: Multivibrators

3-37E3 What is a monostable multivibrator?

A. A circuit that can be switched momentarily to the opposite binary state and then returns after a set time to its original state.

B. A “clock” circuit that produces a continuous square wave oscillating between 1 and 0.

C. A circuit designed to store one bit of data in either the 0 or the 1 configuration.

D. A circuit that maintains a constant output voltage, regardless of variations in the input voltage.

Digital Logic

Key Topic 37: Multivibrators

3-37E4 What is a bistable multivibrator circuit commonly named?

A. AND gate.

B. OR gate.

C. Clock.

D. Flip-flop.

Digital Logic

Key Topic 37: Multivibrators

3-37E5 What is a bistable multivibrator circuit?

A. Flip-flop.

B. AND gate.

C. OR gate.

D. Clock.

A. Flip-flop.

Digital Logic

Key Topic 37: Multivibrators

3-37E6 What wave form would appear on the voltage outputs at the collectors of an astable, multivibrator, common-emitter stage?

A. Sine wave.

B. Sawtooth wave.

C. Square wave.

D. Half-wave pulses.

C. Square wave.

Digital Logic

Key Topic 38:  Memory

3-38E1 What is the name of the semiconductor memory IC whose digital data can be written or read, and whose memory word address can be accessed randomly?

A. ROM – Read-Only Memory.

B. PROM – Programmable Read-Only Memory.

C. RAM – Random-Access Memory.

D. EPROM – Electrically Programmable Read-Only Memory.

C. RAM – Random-Access Memory.

Digital Logic

Key Topic 38: Memory

3-38E2 What is the name of the semiconductor IC that has a fixed pattern of digital data stored in its memory matrix?

A. RAM – Random-Access Memory.

B. ROM – Read-Only Memory.

C. Register.

D. Latch.

B. ROM – Read-Only Memory.

Digital Logic

Key Topic 38: Memory

3-38E3 What does the term “IO” mean within a microprocessor system?

A. Integrated oscillator.

B. Integer operation.

C. Input-output.

D Internal operation.

C. Input-output.

Digital Logic

Key Topic 38: Memory

3-38E4 What is the name for a microprocessor’s sequence of commands and instructions?

A. Program.

B. Sequence.

C. Data string.

D. Data execution.

A. Program.

Digital Logic

Key Topic 38: Memory

3-38E5 How many individual memory cells would be contained in a memory IC that has 4 data bus input/output pins and 4 address pins for connection to the address bus?

A. 8

B. 16

C. 32

D. 64

Digital Logic

Key Topic 38: Memory

3-38E6 What is the name of the random-accessed semiconductor memory IC that must be refreshed periodically to maintain reliable data storage in its memory matrix?

A. ROM – Read-Only Memory.

B. DRAM – Dynamic Random-Access Memory.

C. PROM – Programmable Read-Only Memory.

D. PRAM – Programmable Random-Access Memory.

B. DRAM – Dynamic Random-Access Memory.

Digital Logic

Key Topic 39:  Microprocessors

3-39E1 In a microprocessor-controlled two-way radio, a “watchdog” timer:

A. Verifies that the microprocessor is executing the program.

B. Assures that the transmission is exactly on frequency.

C. Prevents the transmitter from exceeding allowed power out.

D. Connects to the system RADAR presentation.

A. Verifies that the microprocessor is executing the program.

Digital Logic

Key Topic 39: Microprocessors

3-39E2 What does the term “DAC” refer to in a microprocessor circuit?

A. Dynamic access controller.

B. Digital to analog converter.

C. Digital access counter.

D. Dial analog control.

B. Digital to analog converter.

Digital Logic

Key Topic 39: Microprocessors

3-39E3 Which of the following is not part of a MCU processor?

A. RAM

B. ROM

C. I/O

D. Voltage Regulator

Digital Logic

Key Topic 39: Microprocessors

3-39E4 What portion of a microprocessor circuit is the pulse generator?

A. Clock

B. RAM

C. ROM

D. PLL

A. Clock

Digital Logic

Key Topic 39: Microprocessors

3-39E5 In a microprocessor, what is the meaning of the term “ALU”?

A. Automatic lock/unlock.

B. Arithmetical logic unit.

C. Auto latch undo.

D. Answer local unit.

B. Arithmetical logic unit.

Digital Logic

Key Topic 39: Microprocessors

3-39E6 What circuit interconnects the microprocessor with the memory and input/output system?

A. Control logic bus.

B. PLL line.

C. Data bus line.

D. Directional coupler.

C. Data bus line.

Digital Logic

Key Topic 40:  Counters, Dividers, Converters

3-40E1 What is the purpose of a prescaler circuit?

A. Converts the output of a JK flip-flop to that of an RS flip-flop.

B. Multiplies an HF signal so a low-frequency counter can display the operating frequency.

C. Prevents oscillation in a low frequency counter circuit.

D. Divides an HF signal so that a low-frequency counter can display the operating frequency.

Digital Logic

Key Topic 40: Counters, Dividers, Converters

3-40E2 What does the term “BCD” mean?

A. Binaural coded digit.

B. Bit count decimal.

C. Binary coded decimal.

D. Broad course digit.

C. Binary coded decimal.

Digital Logic

Key Topic 40: Counters, Dividers, Converters

3-40E3 What is the function of a decade counter digital IC?

A. Decode a decimal number for display on a seven-segment LED display.

B. Produce one output pulse for every ten input pulses.

C. Produce ten output pulses for every input pulse.

D. Add two decimal numbers.

B. Produce one output pulse for every ten input pulses.

Digital Logic

Key Topic 40: Counters, Dividers, Converters

3-40E4 What integrated circuit device converts an analog signal to a digital signal?

A. DAC

B. DCC

C. ADC

D. CDC

C. ADC

Digital Logic

Key Topic 40: Counters, Dividers, Converters

3-40E5 What integrated circuit device converts digital signals to analog signals?

A. ADC

B. DCC

C. CDC

D. DAC

Digital Logic

Key Topic 40: Counters, Dividers, Converters

3-40E6 In binary numbers, how would you note the quantity TWO?

A. 0010

B. 0002

C. 2000

D. 0020

A. 0010