wired OR question.

Discussion in 'General Electronics Chat' started by toffee_pie, May 15, 2012.

  1. toffee_pie

    Thread Starter Active Member

    Oct 31, 2009
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    Hi Guys,

    what is the best and most low power way to seperate two 5 volt signals? I need to output either one or the other of them.

    diodes and a resistor or a dedicated IC ? (NC7SZ38 )

    i dont think I got resources for a VCC line for a IC so not sure what i can do...:confused:

    would the quiescent draw from diodes and a resistor be much?

    cheers
     
  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    What do you mean, "seperate two 5 volt signals?"
    What are you really trying to do?
     
  3. crutschow

    Expert

    Mar 14, 2008
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    An OR function gives an output high when either one or both of the inputs is high. Is that what you want?

    If you want one or the other but not both, then you need the XOR (exclusive OR) function.
     
  4. bandubalu

    New Member

    May 15, 2012
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    I want to drive mosfet which require 10v and that i hav to draw from microcontroller that has 5v output.. Pls help me
     
  5. bandubalu

    New Member

    May 15, 2012
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    So i want 10v from 5v of microcontroller
     
  6. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Hijack, I suspect...
     
  7. crutschow

    Expert

    Mar 14, 2008
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    Rule #1 for a new member. Do not hijack a post. ;) Please start a new one.
     
  8. bandubalu

    New Member

    May 15, 2012
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    can u tell about this problem
     
  9. bandubalu

    New Member

    May 15, 2012
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    Pls tell about the ics or device
     
  10. bandubalu

    New Member

    May 15, 2012
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    How to create new post
     
  11. toffee_pie

    Thread Starter Active Member

    Oct 31, 2009
    162
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    ok,

    i have a device A giving me 5 volts out and also device B giving me 5 volts out.

    either of the 5 volts will do my load, but i need to seperate them.

    i am not sure how to approach this without having to draw too much current.
     
    Last edited: May 15, 2012
  12. toffee_pie

    Thread Starter Active Member

    Oct 31, 2009
    162
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    eg

    5V1 --------|
    or ------------ > 5V out

    5V2 ---------|
     
  13. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Near the top and the bottom of the page is a New Thread button.
     
  14. Ron H

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    How much current does your load draw?
     
  15. toffee_pie

    Thread Starter Active Member

    Oct 31, 2009
    162
    7
    4/5 watts maximum give or take
     
  16. toffee_pie

    Thread Starter Active Member

    Oct 31, 2009
    162
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    1amp load current
     
  17. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Are you sure your sources can supply 1 Amp each? If so, you can use two 3A Schottky diodes. Look at 1N5820. They will each have about 300mV drop.
    Connect the cathodes together, and to the load. Anodes connect to your sources.
    If you need smaller devices, there are surface mount parts available.
     
  18. toffee_pie

    Thread Starter Active Member

    Oct 31, 2009
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    i think thats too much current... i will check from some smts
     
  19. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    What is too much current? The 3A rating of the diode means it can tolerate that current indefinitely. There are 1A units available, but it is not a good idea to run a component at the limit of it's specs. Also, lower current units will generally have a higher voltage drop.
     
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