Intro to Logic Tutorial

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Postby Spock » Sat 2006 Jun 17 5:18

Luke wrote:... I did that last year in electronics lab! ...


What bothered me at the time was that they showed us a half-adder circuit that we then built on a circuit design board (breadboard, now where did that name come from?) and tested to verify that it worked.

They then showed us a completely different circuit for a full-adder and we did the same thing. It took me about an hour of explanation and demonstration to show them that it would be possible to take two half-adder circuits, add them together, and make a full-adder! To me it was a logical extention of what we were doing. To them, they had never really thought about it. :?

Obviously, the full-adder circuit had been optimized to take the least components. I know how to do that but, at the time, it made more sense to see the intermediate step of two half-adders making a full-adder.

--------------

Thank you for attending todays lecture. Tomorrows lecture will be on how to convert any flip-flop into any other type of flip-flop using nothing but logic diagrams. The result will show which logic gates and components will be required to make the actual physical modification. :roll:
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Postby Luke » Sat 2006 Jun 17 6:13

Spock wrote:... (breadboard, now where did that name come from?) ...

Perhaps because TTL is the "bread and butter" of electronics? :lol: ohh thats bad.

Spock wrote:...It took me about an hour of explanation and demonstration to show them that it would be possible to take two half-adder circuits, add them together, and make a full-adder! To me it was a logical extention of what we were doing. To them, they had never really thought about it. :?

Ahh maybe you set the trend! One of the lab questions was "Show how two half-adders can be combined to make a full-adder circuit", the next was "Design a simplified full-adder" you never know eh...

Spock wrote:...Tomorrows lecture will be on how to convert any flip-flop into any other type of flip-flop using nothing but logic diagrams. The result will show which logic gates and components will be required to make the actual physical modification. :roll:

Toggle to Data? or left foot to right foot }:-> . If it is the latter, can't you just perform a rotation throught the fourth dimension? If it is the former, do enlighten us :mrg:
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Postby Spock » Sat 2006 Jun 17 7:24

Luke wrote:Toggle to Data? ...


Any type to any type and I can show how it's done if you are truly interested. If not, it's been a while since I taught it, so would have to check my notes to make sure I had it right. I would also need to set up some diagrams as digital logic gates are not a normal part of php ... :?

[Added]
OK, found some information:
Logic Gates: http://www.kpsec.freeuk.com/gates.htm

Basic Logic Gates: http://www.ee.surrey.ac.uk/Projects/Lab ... index.html

Flip-Flop Symbols: http://www.play-hookey.com/digital/flip ... mbols.html

The Logic Story: http://www.play-hookey.com/digital/

Logic Component Schematic Symbols: http://www.tpub.com/content/firetrucksa ... 54_228.htm

If you are serious about wanting to learn, I will split off the relevant posts so as not to go off-topic. Probably should anyway but I'm lazy. ;)
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Postby Luke » Sat 2006 Jun 17 8:05

Well don't worry. It has piqued my interest, but I couldn't even draw a truth table for any flip flop, so it would be over my head. Electronics is confusing for me as a physicist as they keep trying to teach us why components behave the way they do instead of just how. }:-< [/b]
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Postby Spock » Sat 2006 Jun 17 9:17

Luke wrote:... they keep trying to teach us why components behave the way they do instead of just how. }:-<


Then it might help if I did, as I would teach you how and not why. ;)
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Postby Luke » Mon 2006 Jun 19 6:42

The http://www.play-hookey.com site is a good reference for electronics. However some of the information in the "optics" section is inaccurate. In particular I have issues with some of the assumptions made about phase relations and energy constraints in the section on the transverse electromagnetic wave.

In terms of converting flip-flops, how about I give it a go when I have some spare time, and you tell me if I get it right? That will save you the hassle of looking it up and finding a way of posting it 8-)
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Postby Spock » Mon 2006 Jun 19 9:29

It's simple enough to do if you know how to manipulate truth tables. Flip-flop 1 and flip-flop 2 are the inputs and the difference in output is the result ... if that makes sense.
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