# Logic Gates · Digital Circuits · GATE ECE

Start Practice## Marks 1

GATE ECE 2022

Consider a Boolean gate (D) where the output Y is related to the inputs A and b as, Y = A + $$\overline B $$, where + denotes logical OR operation. Th...

GATE ECE 2016 Set 3

The minimum number of 2-input NAND gates required to implement a 2-input XOR gate is

GATE ECE 2016 Set 1

The output of the combinational circuit given below is
...

GATE ECE 2015 Set 3

In the circuit shown, diodes $${D_1}$$ ,$${D_2}$$ and $${D_3}$$ are ideal, and the inputs $${E_1}$$ , $${E_2}$$ and $${E_3}$$ are “0 V” for
logic ‘...

GATE ECE 2015 Set 2

In the figure shown, the output ܻ is required to be ܻ Y=AB+ $$\overline C $$$$\overline D $$. The gates G1 and G2 must be,
respectively,
...

GATE ECE 2014 Set 4

In the circuit shown in the figure, if C = 0, the expression for Y is
...

GATE ECE 2013

A bulb in a staircase has two switches, one switch being at the ground floor and the other one at the
first floor. The bulb can be turned ON and also ...

GATE ECE 2011

The output Y in the circuit below is always ‘1’ when ...

GATE ECE 2010

Match the logic gates in column A with their equivalents in column B.
...

GATE ECE 2010

For the output F to be 1 in the logic circuit shown, the input combination should be
...

GATE ECE 2002

If the input to the digital circuit (in the figure) consisting of a cascade of 20 XOR-gates is X then the output Y is equal to
...

GATE ECE 2001

For the ring oscillator shown in the figure, the propagation delay of each inverter is 100 pico sec. What is the fundamental frequency of the oscillat...

GATE ECE 2000

For the logic circuit shown in Figure, the required input condition (A, B, C) to make the output (X)=1.
...

GATE ECE 1997

The output of the logic gate in figure is ...

GATE ECE 1995

The minimum number of NAND gates required to implement the Boolean function $$A + A\overline B $$ $$ + A\overline B C$$ is equal to

GATE ECE 1994

A ring oscillator consisting of 5 inverters is running at a frequency of 1.0 MH$$_z$$. The progagation delay per gate is ______

GATE ECE 1993

Boolean expression for the output of XNOR (equivalence) logic gate with inputs A and B is

GATE ECE 1993

For the logic circuit shown in Figure, the output is equal to
...

GATE ECE 1989

Indicate which of the following logic gates can be used to realize all possible combinational Logic functions:

GATE ECE 1988

Minimum number of 2-input NAND gates required to implement the function, f=($$\overline X $$+$$\overline Y $$)(Z+W) is

GATE ECE 1988

For the circuit shown below the output Fis given by
...

GATE ECE 1988

The minimum number of 2-input NAND gates required to implement the Boolean function Z=A$$\overline {B\,} $$C, assuming that A, B and C are available, ...

GATE ECE 1988

The Boolean function A+BC is a reduced form of

GATE ECE 1988

For the identity AB+$$\overline A $$ C + BC= AB + $$\overline A $$ C, The dual form is

## Marks 2

GATE ECE 2018

The logic gates shown in the digital circuit below use strong pull-down nMOS transistors for
LOW logic level at the outputs. When the pull-downs are o...

GATE ECE 2015 Set 3

A universal logic gate can implement any Boolean function by connecting sufficient number of
them appropriately. Three gates are shown.
Which on...

GATE ECE 2015 Set 1

All the logic gates shown in the figure have a propagation delay of 20 ns. Let A = C = 0 and B = 1
until time t = 0. At t = 0, all the inputs flip (i....

GATE ECE 2015 Set 1

A 3-input majority gate is defined by the logic function M (a,b,c) = ab+bc+ca. Which one of
the following gates is represented by the function M$$\le...

GATE ECE 2014 Set 1

The output F in the digital logic circuit shown in the figure is
...

GATE ECE 2008

Which of the follwing Boolean expression correctly represents the relation between P, Q, R and M1?
...

GATE ECE 2002

The gates G1 and G2 in figure have propagation delays of 10nsec and 20nsec respectively. If the input Vi makes an abrupt change from logic 0 to 1 at
t...

GATE ECE 2001

In the figure the LED
...

GATE ECE 2000

For the logic circuit shown in the figure, the simplified Boolean expression for the output Y is
...

## Marks 5

GATE ECE 2001

For the digital block shown in Figure. 2(a), the output Y=f(S3,S2,S1,S0) where S3
is MSB and S0 is LSB. Y is given in terms of minterms as $$Y\, = \,\...

GATE ECE 2000

The operating conditions (ON = 1, OFF = 0) of three pumps (x,y,z) are to be
monitored. x = 1 implies that pump X is on. It is required that the indica...

GATE ECE 1993

The truth table for the output Y in terms of three inputs A, B and C are given in
table. Draw a logic circuit realization using only NOR gates.
...

## Marks 8

GATE ECE 1992

A combinational circuit has three inputs A, B and C and an output F. F is true only for the following input combinations?
A is false and B is true
A ...