Transistor EXOR gate

Discussion in 'General Electronics Chat' started by Robin Mitchell, Jan 17, 2011.

  1. Robin Mitchell

    Thread Starter Well-Known Member

    Oct 25, 2009
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    Hi everone,

    How do you make an EXOR gate out of transistors?
    I can do it with 3 transistors and two diodes but is there an easier way?

    Thanks
     
  2. tom66

    Senior Member

    May 9, 2009
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    One way to think of XOR (there is no such thing as an exclusive exclusive OR gate) is as a controlled inverter. The input B switches between whether A is inverted or not. So you could implement it by using a mux to switch between A and not A with the input, B.

    Or you could implement the function Q = (not A).B + A.(not B) in diode-transistor logic.
     
  3. Wendy

    Moderator

    Mar 24, 2008
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    I think I have an RTL drawn somewhere, the subject keeps coming up. You want me to dig it up? I like RTL, but it is slow, not immune to noise. It is very easy to understand and reliable though.

    I drew up a complete set of gates using RTL in response to another thread. It was kinda fun.

    BTW, it is either XOR, or NXOR.

    *********************

    Found it...

    Creating an XOR gate
     
    Last edited: Jan 17, 2011
  4. Robin Mitchell

    Thread Starter Well-Known Member

    Oct 25, 2009
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    ooooh yes please :) That would be really nice.....may even...no...will turn into a poster for my new workshop :D

    Logic gates, by bill marsden :)
     
  5. Jony130

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    Feb 17, 2009
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  6. Wendy

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    Mar 24, 2008
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    That was the same link I pointed him too.

    Here is the actual RTL version...

    [​IMG]

    Something to remember, resistors are harder to make on die than transistors.
     
  7. Robin Mitchell

    Thread Starter Well-Known Member

    Oct 25, 2009
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    hang on??
    That AND gate only needs two transistors, have one transistors collector connecting to the other transistors collector and that transistors emitter to the output. Supply into first transistors collector (with resistor) and the inputs connecting into the bases of those transistors (with resistors)
     
  8. Wendy

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    A NOR gate with inverting inputs is a AND gate. If you have a different idea in mind feel free to input it. Like I said in the other thread, every logic family has as signature gate, the NOR gate is the RTL's.
     
  9. Robin Mitchell

    Thread Starter Well-Known Member

    Oct 25, 2009
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    Sorry bill, im thinking of TTL and keep forgetting that yours are RTL XD
    My apologies

    Also, where do you live becuase i think your in america.. AND WHAT TIME IS IT!!!! Im in the uk and its 7AM, but for you....i think someone is staying up late, now go to bed!!! >:|
     
  10. Wendy

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    I work 3rd shift. Work is slow. Nuff said?
     
  11. Ron H

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    Apr 14, 2005
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    In CMOS, I think it would be hard to say what the signature gate is.
     
  12. Wendy

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    Mar 24, 2008
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    I don't know, both OR and AND compete pretty closely.

    From Wikipedia...

    [​IMG]...[​IMG]
    ,,,,,,,,,Not Gate (Inverter),,,,,,,,,,,,,,,,,,NAND Gate

    The fact CMOS acts a lot like a voltage controlled switch makes it pretty simple.

    Something I found interesting about TTL, is the fact that no matter what logic state it is in the current draw remains constant. It isn't low current, but surges are not as likely because of various logic states.
     
  13. Ron H

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    Did you intend to show a NOR gate in place of the inverter? As you (almost) said, NOR and NAND have the same structure when you swap N-channels and P-channels.
     
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