D algoritham for testability circuit

Discussion in 'Homework Help' started by vead, Jul 17, 2014.

  1. vead

    Thread Starter Well-Known Member

    Nov 24, 2011
    I need little help to understand following circuit

    I don't understand image b and c

    look at image b , D=0/1 where 1 represent good circuit and 0 represent bad circuit

    why does A become 1 ?

    look at c diagram if input of inverter is 1 then output will be 0
    and output of inverter will become input for nand gate but here we know only one input of nand gate how we will determine another input
  2. timwhite


    Apr 10, 2014
    "1. Choose a Fault." The entire purpose of this diagram is to work your way through a fault. In (a) they chose a fault at U2, being a 0 going into the input of the U3 gate. Then, at (b) they ask "What would cause this to be a 0," and work their way back through the inverter to the input.

    Hope that helps as just a direct answer to your question.