FYBCS: Semester 1 : Electronics 2 : Previous Year Questions

Unit 1 : Number systems and Digital codes:

2 mark

(i) (11101)gray to binary conversion.

(ii) (479) decimal to BCD conversion.

(iii) (10111101) binary to gray conversion.

(iv) (FAD) hex to decimal conversion.

(v) (207) decimal to binary conversion.

Q. Add the following binar numbers:

1101.01 + 0101.10

Q. Find one's complement of (9D) [hex].

4 mark

Q. Draw logic diagram for HEX to binary conversion.

Q. Write a short note on Alphanumeric codes.

-----Q. Perform (45)-(23) using 2's complement method.

Unit 2: Logic gates and Boolean algebra:

1 mark

-Q. Define minterm.

2 mark

--Q. Draw the symbol and truth table for :

1. 2 input AND gate

2. 2 input OR gate

.3. 2 input XNOR gate.

4 mark

-Q. Convert the given expression into standard SOP form.

Q. Convert given expression into standard POS form:

-----Q. Simplify given expression :

--Q. Simplify given expression using Kmap , Draw simplified diagram.

Q. Construct NOR gate and NOT gate using NAND gates.

Q. Construct NAND gate and NOT gate using NOR gates.

Q. Construct AND gate using only NOT and only NAND gates.

Q. Construct all basic gates using NOR gate.

Q. With suitable diagram explain the working of CMOS NOT gate.

----Q. Define parameters for a logic gate:

i. Fan in

ii. Switching speed.

iii. Logic Levels.

iv. Propagation delay.

v. noise margin.

vi. Power dissipation.

vii. Fan out

Unit 3: Combinational Circuits : 

1 mark

Q. For a decoder having 32 states, number of control lines required.

---Q. For multiplexer having 42 inputs, find number of control lines required.

Q. For demultiplexer having 64 outputs , find the number of control lines required.

Q. Applications of demultiplexer.

4 mark

---Q. Differentiate between encoder and decoder.

----Q. Draw logic diagram and give truth table for:

(i) Half Adder.

(ii) Half Subtractor.

---Q. With neat diagram explain the working of 3x4 matrix keyboard encoder .

---Q. With neat diagram explain the working of 4 bit universal adder-subtractor.

--Q. With a neat logic diagram explain the working of a full subtractor/ full adder.

-Q. Explain working of 4:1  multiplexer using NAND gates.

-Q. Explain the working of  4:1 multiplexer using AND-OR gates.

Q. Explain working of 1 : 4 demultiplexer using AND gates.

-Q. Draw the block diagram of a BCD to 7 segment converter. For the BCD inputs 8 and 3, what will be the seven segment outputs ? Assume common cathode seven segment display type is used.

-Q. Explain working of 3-bit parity generator circuit with suitable diagram.

Q. Explain working of Decimal to binary/BCD converter.