active low & high

Discussion in 'The Projects Forum' started by vultac, Mar 30, 2009.

  1. vultac

    Thread Starter Active Member

    Mar 2, 2009
    142
    0
    Hi guys, when i set my address line high it gives an output of 5V does this mean that it is active high? and the definition of active low would mean that it would goto -5V or would it have a transition from 5V to 0V thx.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
  3. vultac

    Thread Starter Active Member

    Mar 2, 2009
    142
    0
    thx....so this wouuld mean that if i have binary of 1111 which give 5v for all of them and now i found out my devices are active low i would need to set it to 0 to trigger its output?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The one does not follow from the other. A binary value and a logic gate input are not the same thing.

    It is possible to apply four high inputs to a quad input NAND gate, which would cause its output to go low. If that output were connected to another gate, say the reset input of a 7474 flip flop, then that active low reset input would be satisfied, and the flip flop would go to the reset state.
     
Loading...