Logic Gates OR

Basic gate OR is equivalent to two open switch mounted parallel / row as shown in Figure 6 below. The circuit consists of two switches mounted in parallel, a relay and lamp. Lights up when one or two switches A and B are connected (on). Otherwise light will be extinguished only when all the switches A and B disconnected (off). It can be formulated that will happen outputs “1” if one of the switches A = “1” or B = “1”, and it will happen outputs “0” only when the switch electrical circuit: A = “1” and B = “1” ,

Pictures 2:38. The electrical circuit equivalent OR gate

Pictures 2:39. symbol OR gate

The function of the OR gate is:
f (A, B) = A + B

Table 2. Table correctness OR

Pictures 2:40. Input-output diagram OR gate

Input-output diagram is shown as the figure below. At the output A + B will only have a low logic “0” when all inputs – inputs A and B have a logic “0”.