69 lines
3.2 KiB
Markdown
69 lines
3.2 KiB
Markdown
E7A Digital circuits: digital circuit principles and logic circuits; classes of logic elements; positive and negative logic; frequency dividers; truth tables
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- [[E7A01]] (C)
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Which circuit is bistable? #card
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- [[A.]] An AND gate
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- [[B.]] An OR gate
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- [[C.]] A flip-flop
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- [[D.]] A bipolar amplifier
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- [[E7A02]] (A)
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What is the function of a decade counter? #card
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- [[A.]] It produces one output pulse for every 10 input pulses
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- [[B.]] It decodes a decimal number for display on a seven-segment LED display
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- [[C.]] It produces 10 output pulses for every input pulse
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- [[D.]] It decodes a binary number for display on a seven-segment LED display
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- [[E7A03]] (B)
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Which of the following can divide the frequency of a pulse train by 2? #card
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- [[A.]] An XOR gate
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- [[B.]] A flip-flop
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- [[C.]] An OR gate
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- [[D.]] A multiplexer
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- [[E7A04]] (A)
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How many flip-flops are required to divide a signal frequency by 16? #card
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- [[A.]] 4
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- [[B.]] 6
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- [[C.]] 8
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- [[D.]] 16
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- [[E7A05]] (D)
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Which of the following circuits continuously alternates between two states without an external clock signal? #card
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- [[A.]] Monostable multivibrator
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- [[B.]] J-K flip-flop
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- [[C.]] T flip-flop
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- [[D.]] Astable multivibrator
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- [[E7A06]] (A)
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What is a characteristic of a monostable multivibrator? #card
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- [[A.]] It switches temporarily to an alternate state for a set time
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- [[B.]] It produces a continuous square wave
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- [[C.]] It stores one bit of data
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- [[D.]] It maintains a constant output voltage, regardless of variations in the input voltage
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- [[E7A07]] (D)
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What logical operation does a NAND gate perform? #card
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- [[A.]] It produces a 0 at its output only if all inputs are 0
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- [[B.]] It produces a 1 at its output only if all inputs are 1
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- [[C.]] It produces a 0 at its output if some but not all inputs are 1
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- [[D.]] It produces a 0 at its output only if all inputs are 1
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- [[E7A08]] (A)
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What logical operation does an OR gate perform? #card
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- [[A.]] It produces a 1 at its output if any input is 1
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- [[B.]] It produces a 0 at its output if all inputs are 1
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- [[C.]] It produces a 0 at its output if some but not all inputs are 1
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- [[D.]] It produces a 1 at its output if all inputs are 0
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- [[E7A09]] (C)
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What logical operation is performed by a two-input exclusive NOR gate? #card
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- [[A.]] It produces a 0 at its output only if all inputs are 0
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- [[B.]] It produces a 1 at its output only if all inputs are 1
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- [[C.]] It produces a 0 at its output if one and only one of its inputs is 1
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- [[D.]] It produces a 1 at its output if one and only one input is 1
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- [[E7A10]] (B)
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What is a truth table? #card
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- [[A.]] A list of inputs and corresponding outputs for an op-amp
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- [[B.]] A list of inputs and corresponding outputs for a digital device
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- [[C.]] A diagram showing logic states when the digital gate output is true
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- [[D.]] A table of logic symbols that indicate the logic states of an op-amp
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- [[E7A11]] (B)
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What does “positive logic” mean in reference to logic devices?
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- [[A.]] The logic devices have high noise immunity
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- [[B.]] High voltage represents a 1, low voltage a 0
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- [[C.]] The logic circuit is in the “true” condition
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- [[D.]] 1s and 0s are defined as different positive voltage levels
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