understand buffers

Discussion in 'General Electronics Chat' started by twainerm, Jan 14, 2014.

  1. twainerm

    Thread Starter New Member

    Nov 30, 2013
    3
    0
    Hi All,

    I am trying hard to understand buffers. This chapter says that weak signal is boosted by pair of inverters. http://www.allaboutcircuits.com/vol_4/chpt_3/3.html

    how does pair of inverters boost a weak signal?

    what does "weak" mean? what makes a signal weak?

    how exactly buffers help in driving load?

    I am trying to understand this for quite sometime and reading several books but no book seems to explain this clearly.
    Regards,
    Mark
     
  2. WBahn

    Moderator

    Mar 31, 2012
    17,716
    4,788
    Whatever is providing the "weak" signal has a certain limit on how much current it can source or sink while maintaining the voltage at a level that meets the requirements for a logic HI or LO. For instance, many logic gates can sink up to 20mA while maintaining a logic LO. But what if you needed to sink 50mA for your purposes? That signal is too weak. One option is to use a buffer that is capable of sinking at least 50mA and putting it between your signal and your load.
     
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