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From: blw@acsu.buffalo.edu (brian l wybaillie)
Newsgroups: sci.electronics
Subject: schmitt trig. nand configurations
Message-ID: <48711@eerie.acsu.Buffalo.EDU>
Date: 2 Dec 90 15:30:14 GMT
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i have a circuit which uses a 74xx13 schmitt triggered dual 4 input
nand in the following configurations;

                                    74xx13
                                      |
                                      | 
     input ___________                v
                     |
                  ___|______       ___________
                  |  |  |  |______|            \
                  |  |  |_________| _______     \
                  |  |____________|   \____\__   )o-------- output
                  |_______________|             /
                                  |____________/ 



                                   ___________
    input ________________________|            \
                     _____________| _______     \
                     |  __________|   \____\__   )o-------- output
                     |  |  _______|             /
                     |  |  |      |____________/
                    _|__|__|_  
                        |
                        | 
                        + Vcc


	can anyone tell me the difference, if any, these two circuits have
with each other?  the way i see it they are the same, the top one has all
it's inputs tied to one which produces an inverted output.  the bottom one
is only dependant upon one of it's inputs since the other 3 are tied to Vcc.
thus since it is a nand gate it will have the same outcome as the
as the first circuit, (an inverter).
	is there any special reason for configuring it in the two different
ways, i.e. faster responce, or sinking more current?

	thanks in advance for any cunstructive input.

				brian wybaillie


	ps.  sorry for the poor graphics.


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