How can i combine circuits?

Discussion in 'The Projects Forum' started by gvi70000, Oct 14, 2009.

  1. gvi70000

    Thread Starter Active Member

    Oct 4, 2009
    34
    0
    How can i combine the two circuits in a way that when the microphone is off only the photo diode will lit the led an vice verse? Should i use a pnp and npn at the outputs of the op amps?
     
  2. Thav

    Member

    Oct 13, 2009
    82
    0
    Your photodiode simulator is V2 if I remember your last thread correctly? It sounds like you want an exclusive or (XOR) on your output, as in:

    A B X
    0 0 0
    0 1 1
    1 0 1
    0 0 0


    If that's right, you're best off just getting an XOR logic gate chip, because building that with discrete BJTs will be annoying and error prone.
     
  3. gvi70000

    Thread Starter Active Member

    Oct 4, 2009
    34
    0
    Hi,

    can you recommended me some low power xor ic?
     
  4. gvi70000

    Thread Starter Active Member

    Oct 4, 2009
    34
    0
    somebody suggest me to use only a op amp for both circuits
    as i already have a lmv722 I'll use the first half as a preamp and second half as triggerand only one transistor at the output
     
  5. gvi70000

    Thread Starter Active Member

    Oct 4, 2009
    34
    0
    Ok...if i use the op amp as preamp and comparator i will need more switches in my case - limited space - Using the switches i already have i will use each op amp as comparator for the trigger, one switch to toggle between sound and light sensor and one for light/dark. I think this conclude my space usage in the box. The only thing i am concerned about is "Will the circuit do the job?"
    I'm waiting yours opinions.
     
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