trailing edge, leading edge

Discussion in 'General Electronics Chat' started by PG1995, Oct 16, 2011.

  1. PG1995

    Thread Starter Active Member

    Apr 15, 2011
    753
    5
    Hi

    Please have a look on the attachment. You can see my question there. Please help me with it. Thanks.

    Regards
    PG
     
  2. gootee

    Senior Member

    Apr 24, 2007
    447
    50
    Leading Edge means edge at beginning of pulse. Trailing Edge means edge at end of pulse.

    For "low" pulse, leading edge is falling and trailing edge is rising.
     
  3. Papabravo

    Expert

    Feb 24, 2006
    10,135
    1,786
    Leading and trailing are with respect to time. Time is the independent variable, voltage is the dependent variable and voltage is a function of time.
     
  4. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    It is probably easier to think about the terms leading-edge and trailing-edge when you are dealing with pulses that are seperated by a significant interval of time. That way it is clear that you are dealing with a positive pulse or a negative pulse.

    Then it is easy to see that the first edge of the pulse is the leading edge and the second edge is the trailing edge. This is regardless of whether it is a positive going pulse or a negative going pulse.

    hgmjr
     
  5. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    In English, many words have more than one possible meaning. Normally we select the appropriate interpretation more or less unconsciously according to the context.

    When learning new material, we must expect sometimes to come across unfamiliar usages of words that we have previously only seen in different contexts. Sometimes the connection between them may seem natural to us, sometimes it may not.
     
  6. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
    150
    I ride trails on my mountain bike. Some of them go up and some go down. As many have already it's referring to leading or trailing in time.
     
  7. colinb

    Active Member

    Jun 15, 2011
    351
    35
    Though the basic meaning is pretty easy to understand, leading/trailing and rising/falling edge get pretty confusing when you try to wrap your head around all the SPI modes....
     
  8. PG1995

    Thread Starter Active Member

    Apr 15, 2011
    753
    5
    Thank you, everyone. It seems I understand it now.

    Regards
    PG
     
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