E7A Digital circuits: digital circuit principles and logic circuits; classes of logic elements; positive and negative logic; frequency dividers; truth tables

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