XOR stands for exclusive OR. XOR gate compares two values and if they are different its output will be “1.” XOR operation is represented by the symbol ⊕. So Y = A ⊕ B. You can see XOR logic gate symbol in Figure 10 and its truth table right below it.

Figure 17: XOR logic gate.

So its output will only be at “0” when all its inputs have the same value. Otherwise its output will be “1.”

If you need more than two inputs, you will need to add an OR gate like shown in Figure 18.

Figure 18: Expanding XOR inputs.

The most famous XOR gate integrated circuit is 7486 and you can its pinout in Figure 19.

click to enlarge
Figure 19: 7486 integrated circuit provides four two-inputs XOR gates.