AND Gate

An AND gate is a logic gate in which two or more inputs and one output  is present. The output of an AND gate is HIGH only when all the  inputs are in the HIGH state. In all other cases, the output is LOW. The output of the AND gate is a logic ‘1’ only when all of its inputs are in logic ‘1’ state. In all other cases, the output is logic ‘0’. The logic symbol and truth table of a two-input AND gate are shown in Figure.  The AND operation on two independent logic variables A and B is written as Y = AB. Here, A and B are input logic variables and Y is
the output.

AND1

Wired AND gate:

 A wired logic connection is a logic gate that implements Boolean logic using only passive components such as diodes and resistors. A wired logic connection can create an AND gate. The wired AND connection uses a pull up resistor and one diode per input to create this function. The positive voltage from the source is directed away from the output through diodes connected directed towards the inputs. When positive logic that is equal to or greater than that of the source is applied to all inputs the source voltage is directed to the output. The AND gate is capable of an arbitrary number of inputs.

AND2

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