Gates to Circuits

Half Adder

A half adder turns two bits into a sum bit and a carry bit.

logic-computation Every row is intentionally ordered and pinned to the lesson specification.

Example

A half adder turns two bits into a sum bit and a carry bit.

highlighted = computed this step

Build the concrete table

Compute the highlighted logic-table value.

A=0 B=0sum=0 carry=0\begin{array}{c|c}\text{A=0 B=0}&\hlmath{\text{sum=0 carry=0}}\end{array}

Build the concrete table

Compute the highlighted logic-table value.

A=0 B=0sum=0 carry=0A=0 B=1sum=1 carry=0\begin{array}{c|c}\text{A=0 B=0}&\text{sum=0 carry=0}\\\text{A=0 B=1}&\hlmath{\text{sum=1 carry=0}}\end{array}

Build the concrete table

Compute the highlighted logic-table value.

A=0 B=0sum=0 carry=0A=0 B=1sum=1 carry=0A=1 B=0sum=1 carry=0\begin{array}{c|c}\text{A=0 B=0}&\text{sum=0 carry=0}\\\text{A=0 B=1}&\text{sum=1 carry=0}\\\text{A=1 B=0}&\hlmath{\text{sum=1 carry=0}}\end{array}

Build the concrete table

Compute the highlighted logic-table value.

A=0 B=0sum=0 carry=0A=0 B=1sum=1 carry=0A=1 B=0sum=1 carry=0A=1 B=1sum=0 carry=1\begin{array}{c|c}\text{A=0 B=0}&\text{sum=0 carry=0}\\\text{A=0 B=1}&\text{sum=1 carry=0}\\\text{A=1 B=0}&\text{sum=1 carry=0}\\\text{A=1 B=1}&\hlmath{\text{sum=0 carry=1}}\end{array}