Page 42 - DCAP108_DIGITAL_CIRCUITS_AND_LOGIC_DESIGNS

Unit 2: Logic Gates

1. The circuit shown in the below figure are assembled from only NAND gates. Notes
Draw a truth table, including the intermediate points E, F and G, and state
which single gate the output H represents.

2. Design a combination of gates that will accept four inputs A through D and
provide a single output that will be true if two, three, or four of the inputs
are set.

2.5 Review Questions

1. How many types of logic gates are there? Explain in detail.
2. What do you understand by inverter? Explain the suitable truth table.
3. Describe the double inversion using NOT gates.
4. Explain the tri-state gate control and draw the circuit diagram.
5. What is Tri-state logic and explain Tri-state logic inverter with the help of a circuit diagram.
Give its Truth Table.
6. Write the truth table of NOR gate.
7. Find the Boolean expression for the logic circuit shown below:
A
1
B
3 Y

2

8. What are universal gates? Construct a logic circuit using NAND gates only for the expression
x = A (B + C).
9. With relevant logic diagram and truth table explain the working of a two input EX-OR gate.
10. What is a universal gate? Give examples. Realize the basic gates with any one universal
gate.
Answers to Self Assessment

1. (a) 2. (a) 3. (d) 4. (b) 5. (d)
6. (d) 7. (d) 8. (a) 9. (a) 10. (c)
2.6 Further Readings

Digital Electronics—Principles and Applications, by R.L. Tokheim.
Modern Digital Electronics, by R.P. Jain.

www.watson.ibm.com/leo/introelect/IntroElectro_handout.pdf

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