The OR gate, which is composed of two or more inputs and a single output, performs logical addition. The standard symbol for the OR gate is shown in Figure 1-5 and its truth table listed in Table 1-3. The logical operation of the OR gate is such that the output is HIGH (1) when any of the inputs are HIGH, otherwise it is LOW (0). The Venn diagram shown in Figure 1-6 provides an insight into the OR function. The highlighted area represents the function X=A+B.
Figure 1-5 Standard Logic Symbol for OR gate
INPUT |
OUTPUT |
|
A |
B |
|
0 |
0 |
0 |
0 |
1 |
1 |
1 |
0 |
1 |
1 |
1 |
1 |
Table 1-3 Truth table for OR gate
