81. There are________________ basic types of flip-flop based on clock trigger.
a. 2
b. 6
c. 8
d. 4
Answer: (d).4

82. The characteristic equation of any flip-flop describes the __________________ of the next state in terms of the present state and inputs.
a. Impact
b. Behavior
c. Path
d. None of the above
Answer: (b).Behavior

83. The normal data inputs to a flip-flop (D, S and R, J and K, T) are referred to as ________________ inputs.
a. Sequential
b. Asynchronous
c. Synchronous
d. Both a and b
Answer: (c).Synchronous

84. Asynchronous inputs, just like synchronous inputs, can be engineered to be ______________.
a. Active-Medium
b. Active-Low
c. Active-High
d. Both b and c
Answer: (d).Both b and c

85. ___________ and Clear should not be 0 at the same time; otherwise, both the outputs will be 1, which is known as invalid state.
a. Preset
b. Post set
c. Fixed
d. Both a and b
Answer: (a).Preset

86. Which table indicates the input conditions of the flip-flops necessary to cause all possible next state transitions of a flip-flop?
a. T characteristic
b. Truth
c. Flip- flop excitation
d. Excitation
Answer: (c).Flip- flop excitation

87. When a circuit is self- correcting?
a. If there are N-1 cycles among its unused states
b. If there are N-1 cycles among its used states
c. If there are no cycles among its used states
d. If there are no cycles among its unused states
Answer: (d).If there are no cycles among its unused states

88. A PLA consists of two-level____________ circuits on a single chip.
Answer: (a).AND-OR

89. In which of the following types of counters, the flip-flops do not change states at exactly the same time?
a. Decade counter
b. Asynchronous counter with MOD < 2^n
c. Asynchronous ripple counter
d. Cascading asynchronous counter
Answer: (c).Asynchronous ripple counter

90. The number of states through which the counter goes is also known as ____________.
a. Counter
b. Latch circuit
c. Multiplexer
d. MOD number
Answer: (d).MOD number