Same chapter3 marksDifficulty: Medium
Draw the truth table of a full adder and state how many half adders it takes to build one.
Combinational and Sequential Logic Circuits
3 marksDifficulty: Medium
Draw the truth table of a half adder and state its limitation.
Original Khojo Papers practice question — not from a past board paper.
Answer
For inputs A and B the sum is A ⊕ B and the carry is A · B. Its limitation is that it cannot take account of a carry coming in from a previous stage, so it cannot be cascaded to add multi-bit numbers.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
A full adder, with three inputs, overcomes this.
Related questions
From the same topic and chapter, at a similar level.
Same chapter3 marksDifficulty: Medium
What is a multiplexer, and how many select lines does an 8-to-1 multiplexer need?
Combinational and Sequential Logic Circuits
Same chapter3 marksDifficulty: Medium
Distinguish between an encoder, a decoder and a multiplexer.
Combinational and Sequential Logic Circuits
Same chapter3 marksDifficulty: Medium
What is a flip-flop and how does it differ from a combinational circuit?
Combinational and Sequential Logic Circuits
Same chapter3 marksDifficulty: Medium
Distinguish between an SR flip-flop and a JK flip-flop.
Combinational and Sequential Logic Circuits
Same subject3 marksDifficulty: Medium
State and verify the absorption law X + X·Y = X using a truth table.
Boolean Algebra