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From: "petrus bitbyter"
Subject: Re: (de Morgans theorem.....)
X-Newsreader: Microsoft Outlook Express 5.50.4807.1700
Date: Fri, 27 Sep 2002 21:43:49 GMT
NNTP-Posting-Date: Fri, 27 Sep 2002 23:43:49 MET DST
Organization: chello broadband
Well, I'll dive into my teaching experience,
For calculations on binary cicuits we use a Boolean algebra. This algebra
has one unary operator, the NOT (invert) and two binary operators the AND
and the OR. This operators are represented in the three basic logic circuits
the inverter, the and-gate and the or-gate.
For writing formulas we use ! for the NOT operation, we use & for the AND
operation and we use | for the OR operation. Sometimes you may see also /,*
and + respectively.
If you have to invert a signal A you put it into an inverter to become !A.
If you have to OR some signals say B and C you put them into a 2-input
or-gate to become B|C.
Likewise if you want to AND them you put them into a and-gate to become B&C.
Or, if you name the outputs of the circuits X, Y and Z respectively:
X = !A
Y = B | C
Z = B & C
You can combine this functions to become formulas like:
P = (A & B & !C) | !(B & D) | (A & E)
An often required operation needs a gate followed by an inverter. This way
you become the well known nand- and nor-gates. In formulas:
P = !(A & B)
Q = !(E | F)
Now at long last we arrive at de Morgan, who states:
If P = !(A & B) then P = !A | !B and vice versa
If Q = !(E | F) then Q = !E & !F and vice versa
If you invert the result of a binary operation, you may also invert the
variables (inputs) first and then take the other binary operation.
Succes with your course.
"janizoomrider" schreef in bericht
> i've started my degree programme @ uni & this week & tho' previously
> experienced in I.T etc, this is a multimedia course with mountain
> loads of digital electronics etc from the start (of which i'm
> unaccustomed) which obviously means i'm needing to shed loads of time
> (which i'm happy to do) but in that i'm being hit left right & center
> with so many new concepts & the next lecture is tuesday, i'm wondering
> if any kind soul can recommend a site that i can check out that is
> into simplicity in good ol' deMorganology.......(!)
> thx for any replies...
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