AND gate

An AND gate is a gate with multiple inputs and an output, wherein the output if and only returns 1, if present at all inputs 1. It corresponds to the logical AND. In Boolean algebra, the AND operation is represented by • ( time ), & or ∧ and is also known as a conjunction.

Survey

AND gates with a larger number of inputs

An AND gate has two inputs by default ( AND 2 ), but are also available and gates with more than two inputs commercially available. The figure below shows an AND gate with three inputs ( AND3 ).

Including a circuit for a three-input AND gate, which was prepared from 2 implemented with 2 -input gates. AND gates with more inputs can be constructed in a corresponding manner.

Even if the circuit symbol is little information about the internal structure, can - at gate families, are used for both modes of representation - the lower will be considered an indication of a less favorable runtime behavior.

An AND gate can be used for example to control a machine: The machine should run when both hands AND both contacts are actuated foot contacts. Thus, one must link 4 signals, what an AND gate with 4 inputs is needed ( AND4 ).

Realization

AND gate produces as an integrated circuit (IC) by many manufacturers. Standard devices of this type are available, for example under the designation " 7408 " in TTL technology and " 74HC08 " in CMOS technology and includes four AND gates each having two inputs. The exact component name depends on the manufacturer. Logic gates of this type are available for a few cents at most electronics stores.

CMOS

The picture on the right shows the circuit diagram of an AND gate in CMOS technology. Located at the inputs A and B at high potential, then route T3 and T4, where T1 and T2 to block. This is present at T5 and T6 low potential and T5 and T6 leads locks, so the output Y bears high potential. For all other input states is low potential at the output, because T6 is derived.