SUBELEMENT E7 -- PRACTICAL CIRCUITS [7 Exam Questions -- 7 Groups]
E7A Digital logic circuits: Flip flops;
Astable and monostable
multivibrators; Gates (AND, NAND, OR, NOR); Positive and negative
logic
E7A01
(C)
What is
a bistable multivibrator circuit?
A. An "AND" gate
B. An "OR" gate
C. A flip-flop
D. A clock
E7A02
(C)
How
many output level changes are obtained for every two trigger pulses applied to
the input of a "T" flip-flop circuit?
A. None
B. One
C. Two
D. Four
E7A03
(B)
The
frequency of an AC signal can be divided electronically by what type of digital
circuit?
A. A free-running multivibrator
B. A bistable multivibrator
C. An OR gate
D. An astable multivibrator
E7A04
(B)
How
many flip-flops are required to divide a signal frequency by 4?
A. 1
B. 2
C. 4
D. 8
E7A05
(D)
What is
the characteristic function of an astable multivibrator?
A. It alternates between two stable states
B. It alternates between a stable state and an
unstable state
C. It blocks either a 0 pulse or a 1 pulse and
passes the other
D. It alternates between two
unstable states
E7A06
(A)
What is
the characteristic function of a monostable multivibrator?
A. It switches momentarily
to the opposite binary state and then returns after a set time to its original
state
B. It is a "clock" that produces a
continuous square wave oscillating between 1 and 0
C. It stores one bit of data in either a 0 or 1
state
D. It maintains a constant output voltage,
regardless of variations in the input voltage
E7A07
(B)
What
logical operation does an AND gate perform?
A. It produces a logic "0" at its
output only if all inputs are logic "1"
B. It produces a logic
"1" at its output only if all inputs are logic "1"
C. It produces a logic "1" at its
output if only one input is a logic "1"
D. It produces a logic "1" at its
output if all inputs are logic "0"
E7A08
(D)
What
logical operation does a NAND gate perform?
A. It produces a logic "0" at its
output only when all inputs are logic "0"
B. It produces a logic "1" at its
output only when all inputs are logic "1"
C. It produces a logic "0" at its
output if some but not all of its inputs are logic "1"
D. It produces a logic
"0" at its output only when all inputs are logic "1"
E7A09
(A)
What
logical operation does an OR gate perform?
A. It produces a logic "1" at its output if any input is
or all inputs are logic "1"
B. It
produces a logic "0" at its output if all inputs are logic
"1"
C. It
only produces a logic "0" at its output when all inputs are logic
"1"
D. It
produces a logic "1" at its output if all inputs are logic
"0"
E7A10
(C)
What
logical operation does a NOR gate perform?
A. It produces a logic "0" at its
output only if all inputs are logic "0"
B. It produces a logic "1" at its
output only if all inputs are logic "1"
C. It produces a logic
"0" at its output if any input is or all inputs are logic
"1"
D. It produces a logic "1" at its
output only when none of its inputs are logic "0"
E7A11
(C)
What is
a truth table?
A. A table of logic symbols that indicate the
high logic states of an op-amp
B. A diagram showing logic states when the
digital device's output is true
C. A list of input
combinations and their corresponding outputs that characterize the function of
a digital device
D. A table of logic symbols that indicates the
low logic states of an op-amp
E7A12
(D)
In a
positive-logic circuit, what level is used to represent a logic 1?
A. A low level
B. A positive-transition level
C. A negative-transition level
D. A high level
E7A13
(A)
In a
negative-logic circuit, what level is used to represent a logic 1?
A. A low level
B. A positive-transition level
C. A negative-transition level
D. A high level