DE W7 P1

A half-adder adds two binary bits.

• True

• False

A half-adder has a carry output (C_out) only.

• True

• False

A full adder adds two bits and produces two outputs.

• True

• False

A full adder can be realized only by using 2-input XOR gates.

• True

• False

When the input bits are both 1 and the input carry bit is 1, the sum output of a full adder is 1.

• True

• False

A half-adder is characterized by

• two inputs and two outputs

• three inputs and two outputs

• two inputs and three outputs

• two inputs and one output

A full-adder is characterized by

• two inputs and two outputs

• three inputs and two outputs

• two inputs and three outputs

• two inputs and one output

The inputs to a full adder are A = 1, B = 0, C_in = 1. The outputs are

• Σ = 0, C_out = 1

• Σ = 1, C_out = 0

• Σ = 0, C_out = 0

• Σ = 1, C_out = 1

A 3-bit parallel adder can add

• three 2-bit binary numbers

• two 3-bit binary numbers

• three bits at a time

• three bits in sequence

To expand a 2-bit parallel adder to a 4-bit parallel adder, you must

• use two 2-bit adders with no interconnections

• use two 2-bit adders and connect the sum outputs of one to the bit inputs of the other

• use four 2-bit adders with no interconnections

• use two 2-bit adders with the carry output of one connected to the carry input of the other