Buffer

A buffer  is a logic circuit that  amplifies the current or power.  Basically it is used  change the driving  capability  of a logical  circuit. Therefore  it is  sometimes referred as drive. A simple  buffer  and tri state  buffers (active high  and active and low ) are shown  in figure.

A tri  state  buffer  if enabled  provided the same  logic  level of the output  as that  of input  i ,e if input  is at logic  1 then it provides  logic 1 output.