op-amp comparator, Floyd13-3

Discussion in 'Homework Help' started by PG1995, Mar 24, 2012.

  1. PG1995

    Thread Starter Active Member

    Apr 15, 2011
    753
    5
    Hi

    Please have a look on the attachment. Please help me with it. Thanks a lot.

    Regards
    PG
     
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    Q1: The voltage ACROSS D1 and D2, i.e. from cathode of D1 to cathode of D2

    ii: because it's typically in the mV range
    i: because the inverting input is clamped to the output via the diodes, which have 5.4V voltage drop across them at most
    iii: remember that the Opamp will move it's output voltage trying to make both inputs equal? The 5.4V across the diodes will also appear over R1, if you want the same voltage drop across diodes and R1, therefore having zero voltage difference between (+) and (-) inputs

    iv: because it's in general an input having a very high impedance, nA to uA.
     
    PG1995 likes this.
  3. PG1995

    Thread Starter Active Member

    Apr 15, 2011
    753
    5
    Thank you for the help.

    Regards
    PG
     
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