Explore topic-wise MCQs in Electronics.

This section includes 26 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics knowledge and support exam preparation. Choose a topic below to get started.

1.

One example of the use of an S-R flip-flop is as a(n) _________.

A. racer
B. binary storage register
C. astable oscillator
D. transition pulse generator
Answer» C. astable oscillator
2.

When using master-slave flip-flops, the data is entered into the flip-flop on the leading edge of the clock, but the output does not change until the trailing edge of the clock.

A. 1
B.
Answer» B.
3.

For an S-R flip-flop to be SET or RESET, the respective input must be __________.

A. LOW
B. HIGH
C. installed with steering diodes
D. in parallel with a limiting resistor
Answer» C. installed with steering diodes
4.

If an input is activated by a signal transition, it is _____________.

A. edge-triggered
B. toggle-triggered
C. clock-triggered
D. noise-triggered
Answer» B. toggle-triggered
5.

The toggle condition in a master-slave J-K flip-flop means that Q and will switch to their ________ state(s) at the _____________________.

A. inverted, positive clock edge
B. quiescent, negative clock edge
C. opposite, active clock edge
D. reset, synchronous clock edge
Answer» D. reset, synchronous clock edge
6.

A D-type flip-flop is constructed by connecting an inverter between the Set and Clock terminals.

A. 1
B.
Answer» C.
7.

When the S and the R inputs are both HIGH the output of an S-R NOR latch will be unpredictable.

A. 1
B.
Answer» B.
8.

An astable multivibrator is a circuit that:

A. has two stable states
B. is free-running
C. produces a continuous output signal
D. is free-running and produces a continuous output signal
Answer» D. is free-running and produces a continuous output signal
9.

Edge-triggered flip-flops must have _________.

A. very fast response times
B. at least two inputs to handle rising and falling edges
C. a positive-transition pulse generator
D. a negative-transition pulse generator
Answer» D. a negative-transition pulse generator
10.

The S-R, D-type, and J-K flip-flops are all examples of _________________.

A. astable multivibrators
B. bistable multivibrators
C. monostable multivibrators
D. tristable multivibrators
Answer» C. monostable multivibrators
11.

The equation for the output frequency of a 555 timer operating in the astable mode is: . What value of C1 will be required if R1 = 1 k, R2 = 1 k, and f = 1 kHz?

A. 0.33 F
B. 0.48 F
C. 480 F
D. 33 nF
Answer» C. 480 F
12.

J-K flip-flops are often used as switch debouncers.

A. 1
B.
Answer» C.
13.

Pulse-triggered flip-flops are also called _________ flip-flops.

A. master-slave
B. postponed
C. level
D. edge
Answer» B. postponed
14.

The J-K flip-flop eliminates the RACE state when both the J and K inputs are HIGH.

A. 1
B.
Answer» B.
15.

An S-R flip-flop can be triggered by ______, ______, or ________.

A. HIGHs, LOWs, PRESETs
B. edges, levels, pulses
C. HIGHs, LOWs, CLEARs
D. SETs, RESETs, HIGHs
Answer» C. HIGHs, LOWs, CLEARs
16.

The 555 timer can be used in either the bistable mode or the monostable mode.

A. 1
B.
Answer» C.
17.

If both inputs of an S-R NAND latch are LOW, what will happen to the output?

A. The output would become unpredictable.
B. The output will toggle.
C. The output will reset.
D. No change will occur in the output.
Answer» B. The output will toggle.
18.

Which of the following describes the operation of a positive edge-triggered D-type flip-flop?

A. If both inputs are HIGH, the output will toggle.
B. The output will follow the input on the leading edge of the clock.
C. When both inputs are LOW, an invalid state exists.
D. The input is toggled into the flip-flop on the leading edge of the clock and is passed to the output on the trailing edge of the clock.
Answer» C. When both inputs are LOW, an invalid state exists.
19.

An S-R NAND latch with both of its inputs LOW has an output that is _____________.

A. unpredictable
B. floating
C. HIGH
D. LOW
Answer» B. floating
20.

A one-shot is a special type of multivibrator, which must be triggered to produce each output pulse.

A. 1
B.
C. 1
D.
Answer» B.
21.

The truth table for an S-R flip-flop has how many VALID entries?

A. 3
B. 1
C. 4
D. 2
Answer» B. 1
22.

The 555 timer can be used in which of the following configurations?

A. astable, monostable
B. monostable, bistable
C. astable, toggled
D. bistable, tristable
Answer» B. monostable, bistable
23.

A retriggerable one-shot has a pulse width of 10 ms; 3 ms after being triggered, another trigger pulse is applied. The resulting output pulse will be _________ ms.

A. 3
B. 7
C. 10
D. 13
Answer» E.
24.

When both inputs of a J-K flip-flop cycle, the output will:

A. be invalid
B. not change
C. change
D. toggle
Answer» C. change
25.

A basic S-R flip-flop can be constructed by cross-coupling which basic logic gates?

A. AND or OR gates
B. XOR or XNOR gates
C. NOR or NAND gates
D. AND or NOR gates
Answer» D. AND or NOR gates
26.

Which of the following is correct for a gated D-type flip-flop?

A. The Q output is either SET or RESET as soon as the D input goes HIGH or LOW.
B. The output complement follows the input when enabled.
C. Only one of the inputs can be HIGH at a time.
D. The output toggles if one of the inputs is held HIGH.
Answer» B. The output complement follows the input when enabled.