MCQs on Digital Electronics

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01․ When will be the output of a NOT gate is HIGH ?
the input is HIGH
the input is LOW
the input is HIGH and LOW
none of the above

NOT gate acts as an inverter so it has only one i/p and one o/p. Input (0) = output (1). Input (1) = output (0). NOT gate has high output when input is low.

02․ Which is the example of digital device from the given option ?
Record players

The microprocessor is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. The other devices are analog devices.

03․ How many input and output required for demultiplexer ?
one input and one output
number of selection inputs and one output
one input and many output
None of the above

Demultiplexer refers to DEMUX means one to many. It can send one signal to many devices.

04․ How many stable state/states present in flip-flop ?

Flip flop is a bistable multivibrator, so it has 2 stable states.

05․ Why generic array logic (GAL) device was invented ?
Mask programmable
One-time programmable
None of the above

Generic array logic (GAL) device was erasable and re-programmable making prototyping and design changes easier for engineer. The GAL was an improvement of PAL and it can take many PAL devices.

06․ What is the radix of octal number system ?

8 is the radix of octal because octal has only two values from 0 to 7.

07․ What is the requirement of fullsubstractor circuit ?
Three inputs and two outputs
Three inputs and one output
Two inputs and two outputs
Two inputs and three outputs

Subtractor means the difference, for full subtractor we need 2 i/p and 2 o/p, one o/p for difference and other for borrow. It is used for 3 bit binary numbers.

08․ When will be the output of an OR gate is LOW ?
When all input is LOW
When any input is HIGH
When all inputs are HIGH
When any input is LOW

OR gate means A+B = Output, now both of the input low means 0, then output is become 0.

09․ Why encoder is used in the digital electronics ?
To convert non coded information into coded form
To convert coded information into non coded form
It is used to separate address bus and data bus
None of the above

Encoder is used to convert the non-coded form into coded form.

10․ When will be the output of a NOT gate is LOW ?
the input is LOW.
the input is HIGH.
the input is HIGH and LOW.
none of the above.

NOT gate acts as an inverter, it has only one i/p and one o/p. When Input 0 = output 1. When Input 1 = output 0.