Digital Electronics — DU B.Sc. (Hons) Physics Previous Year Question Papers

B.Sc. Hons. - a?hysics)_NEP_UGCF-2o22 Digital Electronics Durat`ion: 3 hours Maximurn marks: 90 Attempt five qriest.ions in all. (a) Show that NAND and NOR gates are universal gates. (b) Explain scale of integrations: SSI, MSI, LSI and VLSI. (c) Explain race around condition in JK Flip Flop. Write two ways by which race around condition may bei prevented. (d) Write excitation table for S-R Flip Flop.. (e) Describe Pin -Out diagram for IC 555. (g) Calculate the fi.equency and duty cycle of the 555 Astable Multivibrator output for 2.(a) Minimize the following expressions using K-map: Design the logic circuit using basic gates. (b) Redraw the following circuit after simplification: 3t (a) Draw the circuit diagram for full adder using NAND Gates. Write its truth table. (8) (b) Distinguisb between a 4 -bit multiplexer and an encoder using appropriate diagrams. Using block diagram realize 8 X 1 multiplexer using two 4 x 1 multipl?xers and a OR Gate and explain its functioning. ( 10) + 4. (a) Draw the circuit diagram of Master - Slave JK Flip Flop using gates. Write its truth table. Explain its working. Explain how race around condition is prevented in this circuit. 5. (a) Design synchronous 3-bit Down-counter using JK Flip Flops. (10) (b) Draw circuit diagram for 4 bit Parallel - in - Serial - out shift register. Explain its working. (8) 6. (a) Draw the circuit diagram of an Astable Multivibrator using IC555 and explain its operation. De.rive an expression for frequency and duty cycle of the ouq3ut wavefom. Discuss the condition for 50% duty cycle. (c)ExplaintheworkingofxoRgateasparityche6ker.