GATE EE
Digital Electronics
Combinational Circuits
Previous Years Questions

## Marks 1

Consider the following circuit which uses a $$2$$-to-$$1$$ multiplexer as shown in the figure below. The Boolean expression for output $$F$$ in terms ...
In the $$4 \times 1$$ multiplexer, the output $$F$$ is given by $$F = A \oplus B.$$ Find the required input $${{\rm I}_3}{{\rm I}_2}{{\rm I}_1}{{\rm I... The output$$Y$$of a$$2-$$bit comparator is logic$$1$$whenever the$$2$$-bit input$$A$$is greater than the$$2$$-bit input$$B.$$The numb... The output$$Y$$of the logic circuit given below is ... Figure shows a$$4$$to$$1MUX$$to be used to implement the sum$$S$$of a$$1$$-bit full adder with input bits$$P$$and$$Q$$and the carry in... The output$$f$$of the$$4$$- to-$$1MUX$$shown in fig. is ... ## Marks 2 A Boolean function$$f\left( {A,B,C,D} \right) = \Pi \left( {1,5,12,15} \right)$$is to be implemented using an$$8 \times 1$$multiplexer ($$A$$is ... Two monoshot multivibrators, one positive edge triggered$$\left( {{M_1}} \right)$$and another negative edge triggered$$\left( {{M_2}} \right)$$are... A$$3$$-bit gray counter is used to control the output of the multiplexer as shown in the figure. The initial state of the counter is$${000_2}.$$The... A$$3$$line to$$8$$line decoder, with active low outputs, is used to implement a$$3$$- variable Boolean function as shown in the figure: The simpl... A$$4 \times 1\,\,MUX$$is used to implement a$$3$$- input Boolean function as shown in figure. The Boolean function$$F\left( {A,\,\,B,\,\,C} \right...
The minimal product-of-sums function described by the $$K$$-map given in Fig. ...
The logic function $$F = AC + ABD + ACD$$ is to be realized using an $$8$$ to $$1$$ multiplexer shown in figure, using $$A, C$$ and $$D$$ as control i...
Match the following ...

## Marks 5

In a digital combinational circuit with $$4$$ inputs $$(A, B, C, D),$$ it is required to obtain an output of logical $$1$$ only for the input combinat...
A $$3$$-input $$2$$-output priority encoder has the following truth table where $$'X'$$ indicate don't care conditions. Realize the logic using NAND...
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