#full adder

Now we can understand the different types of gates and their outputs, we can put them together and build what is called a circuit. A circuit is a connection of gates that we can use to create outputs that depend on the values that we input. For example, a type of circuit we can build is an adder, which adds numbers together. There are two types of adders: half and full.

A half adder is used to add two single bit numbers, outputting the sum, or added result of the inputs, and a carry bit, which can be used to help us calculate the next digits of the equation if more calculation is required. A full adder is able to add three single bit binary numbers.

We can make a half adder using one XOR gate and one AND gate. This is represented in Minecraft below:

We can create a full adder using one OR gate, two AND gates, and two XOR gates. It’s easy to see how the half adder and full adder structures are similar.

Below is a full adder with an automatic carry:

Note: This carry is always active and follows the process of a half-adder carry (Only when both inputs are 1 then the carry is active; otherwise, it is not)

Then we also have a full adder with a manual carry:

Visualizing Digital Logic With EL Wire

[Bob] and [Aubrey] run the System Source Computer Museum a little north of Baltimore, Maryland. For an exhibit, they thought a visual representation of digital logic and came up with a two-bit binary adder. Yes, it’s just a full adder and exactly what you would find somewhere in the second or third chapter of any digital logic textbook. The way they’re illustrating how a full adder works is the killer feature here: they’re using EL wire for all of the wires connecting the gates. The full adder is implemented with an Arduino Mega, but the interface is the real show …read more #BinaryAdder, #ClassicHacks, #DigitalLogic, #ElWire, #FullAdder, #HackadayIo, #Logic