Talk:Logic gate

message: Skoch3 (talk) 19:55, 7 January 2010 (UTC)
thread_title: Making gates from NAND xor NOR

message: The article mentions Nikola Tesla having patented logic gates as US645576, but I looked up that patent, "System of transmission of electrical energy", and it appears to describe a means of transmitting electricity through the air, but nothing to do with logic gates. I've taken the reference to that patent out of the article. --Arteitle 19:51, Mar 7, 2004 (UTC)
The relevant patents are US 723,188 and US 725,605 granted in 1903.  They were filed as one application in July 1900 but subsequently divided.  I have added them to the text.  Conception of the idea was at least as far back as 1896, '...I have an instinctive knowledge of the same...' Tesla said during the interference deposition for the patent, (US Patent Office Interference No 21,701, Systems of Signaling, Nikola Tesla vs. Reginald A. Fessenden, 1902, reply to question 9, August 5th 1902)--Smark33021 21:32, 23 Dec 2004 (UTC)
replies: text: I've looked at the patents and they are for a signalling system, not a logic gate.  Can someone tell me what relevance these patents have to logic gates? There's no mention of a logic gate in the claims, and the signalling system seems to rely on signals at different times, not at the same time, to operate a receiver. I wish I could point to an example of an "and" function used before the dates of these patents, I'm pretty sure this pre-dates electronics in  general - if nothing else the Strowger switch must have had logic at least as complicated as an "and" gate and it was patented a decade earlier. --Wtshymanski 02:31, 27 Apr 2005 (UTC)

text: I agree, the Tesla patents are describing a type of frequency-keying modulation scheme.  There is no mention of logic circuits, nothing in the diagrams to even indicate how he would match patterns of frequency keyings.  I believe the comment about Tesla should be delete. DonPMitchell (talk) 20:15, 21 August 2012 (UTC)
thread_title: Tesla patents

message: I'm new here, so I don't want to make any changes. I shall note, however, that logic gates used in digital integrated circuitry do not operate in this manner. The author is conveying the idea that a logic gate either allows a signal to pass (in his diagram from left to right) or doesn't allow a signal to pass. While this seems sensible to the novice, it is not correct. 
The reason that the author's conception of logic gate cannot be used in digital circuitry is that when a signal is not allowed to pass--for instance, if one transistor in his AND gate is OFF--the signal (technically the voltage level) on the OUT end of his logic gate is ambiguous, or "floating" in electrical engineering parlance. 
:I agree with you.  The inaccuracy could be fixed in two ways: (1) delete the switch diagrams and the text that refers to them, or (2) correct the switch diagrams by adding pull-up resistors (as in open-collector logic) or complementary switches (as in CMOS and TTL logic) or adding loads to the circuits (as in relay logic).  Option 2 sounds horribly complicated, so I am tempted to go for option 1. Anybody else care to comment? -- Heron 21:32, 5 Jul 2004 (UTC)
replies: text: I take the point, but I'm not sure I agree. The diagrams are not meant to indicate how an actual logic gate necessarily works, but what it is doing in principle. I think that's a better intention for the article - to show how an AND function for example can be illustrated in a manner that is fairly intuitive to most people. Most people can understand the operation of simple switches, whereas the operation of a transistor is less clear to most. In addition, there are hundreds of ways to actually implement gates in real integrated circuits - a TTL circuit will differ from a CMOS, so which one would you use? None of them represent a single, "one true way" to make a gate, even if CMOS for example might be possibly the most usual way. Perhaps the wording should be altered to make it clear that the diagrams are only conceptual (though in terms of logic they could be built and would generate the truth tables given - so they are also practical in that sense). The article can provide links to the pages that deal with particular technologies, and those pages could include diagrams showing how logic gates are built with those technologies. Graham 22:52, 5 Jul 2004 (UTC)
replies: text: I just took a chainsaw to the article and separated the content into a switch/relay logic section and a semiconductor logic section.  This way, I hope to prevent any mistaken idea that the two types of logic might be interchangeable, whilst preserving the content that user:Dysprosia painstakingly added. -- Heron 09:07, 6 Jul 2004 (UTC)

text: A good point. Switches and relays are cascadable though, so it could easily be conveyed by that, with a note to the effect that it is important and applicable to digital solid state circuits too. By the way, great job Heron! Graham 12:56, 6 Jul 2004 (UTC)
replies: text: Thanks :-)  I added a note on cascading semiconductor logic, but I haven't done the same job for relays yet.  I have a feeling that this article is a sleeping giant, with the potential to turn into a "How Computers Work: from Babbage to Qubits" essay.  If it starts to get out of hand, we may need to split it up. -- Heron 13:57, 6 Jul 2004 (UTC)
replies: text: I think that should be resisted. The article is simply about the Logic Gate as a functional concept - it actually isn't about how they are implemented by particular technologies. There are better places for much greater expansion of that, which can link back here for those that need to know the fundamental principles. I see this as a foundation article - interested readers can follow links to other places to get more detail, or follow a link back here if they were overwhelmed by to much technicality. Graham 23:40, 6 Jul 2004 (UTC)
replies: text: I agree.  I was stating a fear, not an intention.  It would be good, though, to have a list of all the implementations we can think of, with links to the relevant articles. -- Heron 08:28, 7 Jul 2004 (UTC)

text: I agree. The concept of "cascadable" logic is key. And logic gates do *not*, in general, simply pass or not-pass a signal. Someone please make a nice picture that reflects reality better. (Or else I threaten to inflict my feeble efforts to draw them). --DavidCary 05:57, 15 Jan 2005 (UTC)

text: It should be noted that semiconductor logic gates are not conductive in both directions, as the input signal acts as a 'trigger' to allow current out of the output, rather than allowing current straight through from input to output. However, the following mechanical varitions do show the basic priciples of the gates without detailing the precise internal workings. For information about how modern semiconductors really work, see CMOS.--Jjbeard 05:51, 25 December 2005 (UTC)

text: Mmkay, I was wrong about "electronic logic gate" not being a common expression. Perhaps a sub-article would be justified then. Tijfo098 (talk) 18:57, 7 April 2011 (UTC)
thread_title:  very misleading 

message: Where is the tri-state article ?
This is clearly not the right article to talk about tri-state tristate 3-state logic gates (such as the 74356, the 74HC125, etc.). Is "transmission gates" really the best place ?
Where in the encyclopedia is the right place ?
:Looks like a separate article doesn't exist yet. I'd suggest tristate logic should be the title. However, note that the term itself is inaccurate - tristate logic is not a three-state logic system at all (i.e. trinary), but just binary logic which can be connected or disconnected to e.g. a common bus line. While this ability is important in practical electronic logic systems, it's not really all that exciting - maybe a two or three line paragraph here would be sufficient. Graham 21:53, 23 Dec 2004 (UTC)
replies: text: Tri-State, or "Three State" gates belong in an article relating to bus logic. The purpose behind this is to allow multiple modules composed of logic gates and registers to share a common bus to connect to other modules. It could become part of an article on MUX gates as those can serve a similar function inside FPGAs/ASICs. They are also available as gates in the same packaging and logic families as any other logic type (TTL, CMOS, ECL, etc.)72.8.4.74 (talk) 16:49, 21 August 2013 (UTC)
replies: text: Excellent. If the term is inaccurate, then this is an excellent opportunity for this encyclopedia to teach me a more accurate term by defining the inaccurate term as a redirect pointing to the more accurate term. And the more accurate term would be ... what ? --DavidCary 05:57, 15 Jan 2005 (UTC)
replies: text: Rightly or wrongly, it has always been called '3-state' or 'three-state' logic.  Note that 'tri-state' is a registered trade-mark of National Semiconductor (as pointed out in this PDF datasheet, for example, and mentioned in this comment on a book by Sid Katzen), so we should probably avoid using this as an article title.  Everybody else (Texas Instruments, Fairchild, Philips etc.) calls it '3-state'.  In the field of multivalued logic, the term '3-value' is used to describe trinary logic.  --Heron 12:21, 15 Jan 2005 (UTC)
replies: text: Correct. See, for example, the IEEE Dictionary, IEEE Std 91 symbol 3.3-8, and IEC 60617-12 symbol 12-09-08.  —Preceding unsigned comment added by 71.232.120.146 (talk) 21:26, 8 June 2010 (UTC)
thread_title:  tri-state logic 

message: Am I seeing things or are the 'alternate AND' and 'alternate OR' labels switched on the diagram? For example: De Morgan's law says that P AND Q = NOT ((NOT P) OR (NOT Q)), i.e. there is an OR gate in the 'alternate AND' gate and vice versa. Also, following the circuits visually, it looks like they are switched. Varuna 22:22, 2005 Mar 10 (UTC)
: Aha! I'm not the only one to think that.  I'm going to switch the captions. --Wtshymanski 16:38, 12 Apr 2005 (UTC)
thread_title:  diagrams 

message: I know that from several citations I've seen, that it is known that an "AND" gate will produce more heat than a "NOT" gate, because under quantum theory, information is destroyed and is released as heat (information is a very weird property in quantum theory), whereas an "NOT" gate merely converts information. Would it be good to try to elaborate some of this issue here? -- Natalinasmpf 03:35, 19 Apr 2005 (UTC)
replies: text: My opinion is not to clutter the article up with deeply theoretical and abstract ideas - put it in an article linked to quantum theory  but I think it has no place in a discussion of real-world logic. I'd like to see the cites - can you provide a link that explains this in terms accessible to a non-physicist?  Since anything you can do with an OR gate you can do with enough ANDs and inverters, and the reverse, I don't really see the fundmental reason for this observation. --Wtshymanski 19:45, 19 Apr 2005 (UTC)

text: Whoops, I meant a "NOT" gate, not an "OR" gate,. But logic gates in essence deal with logic itself - I think perhaps some mention about quantum theory (which is real-world, after all) because it entails what the nature of logic really is. And you may accomplish a function with a different setup, but the question in physics becomes, is it efficient? The theory goes that quantum logic gates must eliminate the wasted heat (as information is destroyed in an AND gate: two inputs produce an output where you cannot reverse back to deduce the input), else it would create inteference which is more of an issue for a quantum processor. Oh, I found this: , it cites the heat produced from destroyed information. And this too , this , and this . All these cite the production of heat due to the fact information is destroyed (heat being a byproduct of electrical resistance being a secondary product, heat produced by information destruction is way more). (Oh some of the proposed improvised quantum gates to make up for the elimination of such gates are also trinary gates). -- Natalinasmpf 23:39, 19 Apr 2005 (UTC)
replies: text:  Natalinasmpf, I think explaining this "here" in Wikipedia would be good. But rather than "here" at logic gate, I think reversible computing is a better place. --68.0.124.33 (talk) 16:25, 8 January 2009 (UTC)
thread_title:  Logic gates and quantum physics 

message: Right - Ive had a good hack at the article and have made the first section especially more readable. I have lined up all the switch digrams with the relevant truth table and have also put these next to the relevant paragraph, and put each one in its own little section (i know it makes the ToC longer, but hey) I've also uploaded a modified version ofthe Alternate AND/OR diagram to show the NAND/NOR (I hope dypsrosia doesn't mind) gates. Also, I have done an article on making gates form NAND gates only, and uploaded shiny new blue jpgs of every gate and the NAND equivalent.
I've uploaded a new version of the little summary table thing (Truth2.jpg), and done pages for the XOR and XNOR gates (IC Pinouts and stuff), rather than for the logical process. These are now under XOR_gate and XNOR_gate. the XOR and XNOR articles both have updated headers giving directions.
This article also needs directions to those pages, perhaps when the other pages to do with the actual gates are done...
Also can someone do new versions of the rectangular symbols the present ones look a bit old and tatty...something like the 'military' symbols on this page. Also someonee might want to think about changin any links to the blue symbols to the military black and white ones if they would be better that way (so, for example NOT the ones in the diagrams on the NAND_logic page, but the symbol at the top of the XOR page maybe).
--Jjbeard 05:35, 25 December 2005 (UTC)
thread_title:  General Tidy Up 

message: Your table markup could be simplified a lot.
INPUT
OUTPUT
A
B
A AND B
0
0
0
1
0
0
0
1
0
1
1
1
INPUT	INPUT	OUTPUT
A    	B    	A AND B
0    	0    	0
1    	0    	0
0    	1    	0
1    	1    	1
Maybe not as pretty, though.  Just a thought... — Omegatron 22:08, 23 January 2006 (UTC)
thread_title:  Tables 

message: "They are primarily implemented electronically but can also be constructed using electromagnetic relays, electronic diodes, fluidics, optical or even mechanical elements."
In this part I will delete "electronic diodes" because they are included formerly in "implemented electronically".
User:Vanished user 8ij3r8jwefi 15:41, 6 February 2006 (UTC)
thread_title:  {Electronicaly} 

message: occasionally i've come accross symbols with the bubbles on the inputs (e.g. a NAND gate would be drawn as an or symbol with a bublle on each input). The idea being that you keep the core symbols for thier logical function and use the bublles to indicate a lines active state (then if you have a bubble feeding a non-bubble or vice-versa you have located a potential design error).
Anyone else encountered theese and do you think we should mention them? Plugwash 23:28, 12 February 2006 (UTC)
replies: text: I agree and a while back I did add something to this effect in the symbols section. I feel it would be useful to enhance the disgram to include these, as it helps to reinforce what the text is saying. Bubbles on the inputs are very common, and are a useful design aid too. Graham 02:12, 13 February 2006 (UTC)
replies: text: Yes, they are useful, but I would suggest adding them in a new section called "De Morgan equivalent symbols" or something. Adding them next to the standard symbols would cause an information overload for most readers. --Heron 13:15, 15 February 2006 (UTC)
thread_title:  a third set of symbols 

message: what is a INHIBIT logic gate? V8rik 22:34, 20 April 2006 (UTC)
replies: text: A 2-input inhibit (INH) gate implements the function A ^ 'B (A XOR NOT B). As far as I can see, this is the same as XNOR. Graham 08:10, 21 April 2006 (UTC)
thread_title:  INHIBIT logic gate 

message: I would like to publicize the article CMOS#Example: NAND gate which gives a clear physical layout of a NAND gate (The A and B inputs are implied; you would have to add metal layers to pads surrounding this gate). By the repeated application of the Sheffer stroke operator (NAND), it is possible to build up combinations of NANDs to yield the other logic gates, of course. --Ancheta Wis 09:16, 28 April 2006 (UTC)
thread_title:  NAND gate 

message: Excelent article, very usefull. Thanks to all editors. --201.6.161.117 04:56, 10 September 2006 (UTC)
replies: text: Indeed. Unlike many articles I read, this one actually explains how the subject works, something that articles tend to miss. I learned a ton of info from reading this page. Good job! --The Prophet Wizard of the Crayon Cake 21:36, 28 September 2006 (UTC)
thread_title:  Congrats 

message: I think it would be really nifty if this article on logic gates had (or linked to) a drawing/schematic for each known implementation of logic gates.
We have ladder logic and some of the many kinds of transistor-based logic gates.
I want to add hydraulic "spool valve" logic gates and neon lamp logic gates.
The neon lamp article mentions
"In the 1960s General Electric (GE), Signalite, and other firms made ... neon lamps for electronic uses. They even devised digital logic circuits, binary memories, and frequency dividers using neons."
I understand how to make logic gates out of transistors. 
How is it possible to make logic gates out of neon bulbs?
With a bit of googling, I've found
a schematic for a 3 bulb sequential flasher/oscillator ,
and photographs of a neon bulb ring counter .
Could some help me reverse-engineer a schematic for that ring counter,
or help me puzzle out some other logic circuit (NOT, NAND, NOR) using neons?
(Using neons, diodes, resistors, and capacitors -- but no integrated circuits or discrete transistors or relays).
:The "neon logic" described above did not use simple neon lamps, but rather something similar to electron tubes, that instead of being vacuum were filled with neon gas. Examples were counter circuits, where an input pulse triggered the discharge from one "counter segment" to the next "counter segment" through a cunning layout of the "anodes" "cathodes", and "trigger electrodes" that made up the counter segment. The electrodes were laid out in a ring, so the "last" electrode again triggered the "first" electrode and also outputted a pulse for the next counter tube. The neon light, of the currently ignited electrode could be seen from the outside, so these counter tubes worked as ring counters and indicators at the same time, they were used for atomic clocks. The principle behind it that the neon between the "anode" and "cathode" of the neon tube could be ignited using a separate "trigger electrode", much like a thyristor. Once triggered the neon lamp staid ignited until the current flow was interrupted. Such a tubes were referred to as decatrons  
:I am not aware that circuits that used a OR or AND port structure were constructed with these kind of  tubes, but it's possible. It's better to see the neon tube as a kind of "memory element" though. Mahjongg (talk) 11:27, 30 April 2008 (UTC)
thread_title:  neon bulb logic 

message: NOR_gate has it's own article, while NAND_gate points back to this article.  Is there a NAND_gate article coming, or is the NOR_gate article going to be merged into this one?  I would rather see a separate NAND article myself. Ken6en 08:10, 30 October 2006 (UTC)
thread_title:  NAND gate article 

message: Are the values of Not A and Not B transposed?
: The article miss-represents the NOT gate. A not gate has 1 input and 1 output. The ouput is NOT the input. So if the input is 1 the output is 0. A two input not gate would have to have two outputs, one for each input.--155.144.251.120 00:37, 11 January 2007 (UTC)
replies: text: I created a new version of the symbol with only one input, but for some reason the author of the image has created a two-input version from a previously one-input version. OK to change? Well, maybe I should read the standard :)--Wormsie 14:23, 25 September 2007 (UTC)
replies: text: I went ahead and reverted the image with a comment.  Hopefully he'll make a better one now. Dicklyon 02:20, 26 September 2007 (UTC)
thread_title:  Truth Table Values 

message: Should it not be added to the intro paragraph that logic gates can be formed out of several neurons?  —Preceding unsigned comment added by 140.247.44.93 (talk) 19:34, 6 November 2007 (UTC)
thread_title:  Neurons? 

message: Is there any chip commercially available with a million logic gates? I am not sure if the number of logic gates match the number of transistors.Anwar (talk) 17:24, 10 May 2008 (UTC)
thread_title:  Million-gate chip 

message: Is there a connection between what is known as 'relay logic' and the topics covered here? It seems that people are using on this page what looks similar to the diagrams used in relay logic. So, is relay logic some kind of basic ingredient to depicting logic gates? Peeceepeh (talk) 14:42, 30 June 2008 (UTC)
replies: text: Relay logic is the implementation of logic gates in electromechanical relays, like in old telephone switching circuits and pinball machines. Dicklyon (talk) 16:20, 30 June 2008 (UTC)
thread_title:  Relay Logic? 

message: Why is the output of a logic gate usually named Q? --Abdull (talk) 20:37, 28 August 2008 (UTC)
replies: text: No one knows. Most electronic terms no one really knows. They go back 80 - 100 years or more and into different languages. No one knows why Q, or even J/K for flip flops, or even Vcc/Vdd for power sources was used. Alot of universities claim to have invented most of them. Q is probably simply because it was meant to O for output , but O looks like binary zero, so they put a little mark on it and it eventually became Q.--155.144.40.31 (talk) 05:56, 1 September 2008 (UTC)
replies: text:  IMO its still recent history, searching a bit reveals the true reason behind it. Daiyusha (talk) 07:03, 9 September 2016 (UTC)

text: 155, In "JK flip-flop", JK stands for the initials of the designer Jack Kilby. It was invented at Texas Instruments in Dallas. --Ancheta Wis    (talk  | contribs) 02:42, 26 March 2014 (UTC)

text: Most probably Q is used instead of O (as in Output). However, O may be confused with 0, especially if hand-written, but Q resembles O and it is visually distinct from 0. I assume this is something similar with the fonts that distinguish between O and 0 by having the 0 slashed. But this is just a guess without a reference to back it up.148.64.26.230 (talk) 14:19, 6 August 2021 (UTC)
thread_title:  A, B, Q? 

message: If I understand "A Tinkertoy computer" by A. K. Dewdney correctly,
a set of things is is "computation universal" if, given sufficient quantities of those things, you can build a Turing complete machine out of it.
When this article mentions that "diode logic... is an incomplete form of logic. ... To build a complete logic system, valves (vacuum tubes) or transistors can be used.",
by "complete" I think it means the same kind of "computation universal".
The "functional completeness" article seems to be about highly abstract "logical connectives" in formal logic -- is there some other article that focuses more on the various concrete devices that are "computation universal"?
However, the functional completeness article is the closest thing Wikipedia has to this concept of "computation universal" that I know about, so -- until I find a better article -- I'm going to link that phrase in this article to the "functional completeness" article.
--68.0.124.33 (talk) 04:45, 14 September 2008 (UTC)
thread_title:  computation universal 

message: I've made a new table for the logic functions. I put it in a template here, as it seems to me that this could be useful for other pages.
INPUT 	A                  	0	0	1	1		Meaning
INPUT 	B                  	0	1	0	1		Meaning
      	                   	 	 	 	 		
OUTPUT	FALSE              	0	0	0	0		 Whatever A and B, output is false. Contradiction.
OUTPUT	A AND B            	0	0	0	1		 Output is true if and only if (iff) both A and B are true. 
OUTPUT	A \not\rightarrow B	0	0	1	0		 A doesn't imply B. True if A but not B.
OUTPUT	A                  	0	0	1	1		 True whenever A is true.
OUTPUT	A \not\leftarrow B 	0	1	0	0		 A is not implied by B. True if not A but B.
OUTPUT	B                  	0	1	0	1		 True whenever B is true.
OUTPUT	A XOR B            	0	1	1	0		 True if A is not equal to B.
OUTPUT	A OR B             	0	1	1	1		 True if A is true, or B is true, or both.
OUTPUT	A NOR B            	1	0	0	0		 True if neither A nor B.
OUTPUT	A XNOR B           	1	0	0	1		 True if A is equal to B.
OUTPUT	NOT B              	1	0	1	0		 True if B is false.
OUTPUT	A \leftarrow B     	1	0	1	1		 A is implied by B. False if not A but B, otherwise true. 
OUTPUT	NOT A              	1	1	0	0		 True if A is false.
OUTPUT	A \rightarrow B    	1	1	0	1		 A implies B. False if A but not B, otherwise true.
OUTPUT	A NAND B           	1	1	1	0		 A and B are not both true.
OUTPUT	TRUE               	1	1	1	1		 Whatever A and B, output is true. Tautology.
I've put in links to the more obscure functions (implication, non-implication, etc). It seems to me that the current explanatory text under the table is a bit confused, especially as the material implication is what is usually meant by A\rightarrowB, rather than logical implication (=entailment). While the two are very closely related, the material implication is the logical connective that links values in a truth table. Inductiveload (talk) 02:32, 28 January 2009 (UTC)
thread_title:  Logic function table 

message: What is discrete logic? This term currently redirect to logic gate, but it is not explained what it means. Thanks, --Abdull (talk) 23:31, 8 February 2010 (UTC)
replies: text: Discrete logic is logic (built using discrete components, or using IC technology) that "contains" single (OR, AND, NOR or NAND) gates. In the past these were RTL, DTL or TTL gates built with discrete components, that is resistors, diodes and transistors. Lately the term is more often used to describe single gate IC's, like the 74LVC1G00, that contains a single NAND gate in a SOT-23-5 package (which is normally used for transistors). Mahjongg (talk) 00:06, 9 February 2010 (UTC)
thread_title:  Discrete logic? 

message: I have made some minor edits correcting the "Symbols" section. As the chairman of IEEE SCC11.9 and U.S. delegate to IEC TC3 WG2 over the many years the respective standards were written and revised, I am quite certain of the accuracy, so please forgive my presumptuousness in editing directly. Feel free to contact me if you have any questions.
-Tom Smith
 smith@alum.mit.edu  —Preceding unsigned comment added by 71.232.120.146 (talk) 21:13, 8 June 2010 (UTC)
thread_title:  Symbols 

message: This article is very unclear. I opened it wondering what a logic gate is, and closed it with no greater understanding than I came with. It explains logic gates in great detail to those who already have an idea of what they are, but offer no insight to those who don't.  —Preceding unsigned comment added by 90.36.15.143 (talk) 08:59, 16 August 2010 (UTC)
thread_title:  Unclear 

message: The article does not reveal the fundamental idea behind logic gates at all; it does not show how logical functions are implemented by various electronic circuits. Background (as it is written) is more suitable as an introductory part of Logic family. Circuit dreamer (talk, contribs, email) 19:35, 7 April 2011 (UTC)
thread_title:  The basic idea behind logic gates is not revealed 

message: These changes look like vandalism: http://en.wikipedia.org/w/index.php?title=Logic_gate&action=historysubmit&diff=448953348&oldid=448552259
Perhaps someone more experienced could check and if needed undo them? 88.115.123.211 (talk) 18:20, 7 September 2011 (UTC)
replies: text: Fixed, I hope. --Wtshymanski (talk) 18:29, 7 September 2011 (UTC)
thread_title:  Possible vandalism (7 Sep 2011) 

message: Can we create unit cell using logic gates which when stacked with itself can behave like Universal Turing Machine with head being single signal moving between cells? I am trying to implement Wolfram (2,3) UTM, but it works wrong  — Preceding unsigned comment added by 83.21.106.70 (talk) 18:49, 8 March 2012 (UTC)
replies: text: I am not sure what you mean by unit cell, however, both NOR and NAND gates are universal gates. As such, given enough of them one could construct every conceivable machine/algorithm. --CyberXRef☎ 01:51, 24 March 2014 (UTC)
thread_title:  Turing logic gate? 

message: There are a bunch of places such as in the symbols section where it says something along "In practice, these gates are built from combinations of simpler logic gates." (talking about XOR). This is a very misleading statement. "In practice" there are so many things that get considered that how it's actually implemented various wildly as to make that statement obsolete. Many times standard cell for XOR which would be used around (XOR2, XOR3, XOR4, etg..) as well depending on the requirements. There are simply way too many way these things are made to fit in one sentence "In practice, ...". --CyberXRef☎ 02:13, 24 March 2014 (UTC)
thread_title:  Symbols - "in practice" 

message: Since the page Discrete_circuit seems unnecessary, I think it's best to remove the "redirects here, for x see y".
Discrete_circuit should redirect to Electronic_circuit instead, what do you think?
See also: https://en.wikipedia.org/wiki/Talk:Discrete_circuit#Removal_of_page--Tielemans.jorim (talk) 17:01, 31 May 2015 (UTC)
thread_title:  Remove "redirects here, for x see y" 

message: The text here (starting at "In electronics, a NOT gate is more commonly called an inverter") appears to be taken from the text under the NOT gate in the table on this page. The copyright date of the book is 2014, and the text was on the Wikipedia page as of 2013, so it seems unlikely that Wikipedia is the guilty party. The book doesn't seem to provide a citation, nor be under an acceptable license - furrykef (Talk at me) 15:06, 18 March 2016 (UTC)
replies: text: It wouldn't be the first time I'd been plagiarized (or those standards). I suppose it's a compliment. You could always provide a user review. :-) Note, though, that Wikipedia's rules are that "Work submitted to Wikipedia can be edited, used, and redistributed — by anyone — subject to certain terms and conditions." The text was added to this Wikipedia article at 03:01, 19 June 2010, to be exact. -Tom  — Preceding unsigned comment added by 73.47.87.95 (talk) 23:09, 7 April 2016 (UTC)
thread_title:  Possibly plagiarized by Introduction to Digital Electronics 

message: The symbols shown in the main article for exclusive-OR are defined in IEC 60617-12 and IEEE Std 91 as an exclusive-OR function only for two inputs (IEEE symbol 5.1-11, IEC symbol 12-27-09). There is no defined distinctive-shape symbol with more than two inputs for any function other than AND, OR, and their inverts.
For rectangular-shape symbols, there are a series of related symbols that have defined meanings with multiple inputs. The IEEE symbols listed below can be found as IEC symbols 12-27-01 through -09.
"=m" - IEEE symbol 5.1-6, m and only m function, of which "=1" (5.1-11) is a special case. The output is true iff exactly m inputs are true.
">=m" - IEEE symbol 5.1-5, threshold function, of which ">=1" (5.1-1) is a special case. The output is true iff at least m inputs are true.
">n/2" - IEEE symbol 5.1-7, majority function. The output is true iff more than half the inputs are true.
"=" - IEEE symbol 5.1-8, identity function. The output is true iff all inputs are in the same state.
"2k+1" - IEEE symbol 5.1-9, odd function. The output is true iff the number of true inputs is odd.
"2k" - IEEE symbol 5.1-10, even function. The output is true iff the number of true inputs is even.  — Preceding unsigned comment added by 73.47.87.95 (talk) 16:52, 2 July 2016 (UTC)
thread_title:  Clarification of symbols for exclusive-OR and relatives 

message: I tried to add one of the OR boolean algebra symbols as listed on the List of logic symbols page, but it was reverted as lacking a reference.  
Currently AND gate lists A\ \text{. } B, A \& B as notations but not A \wedge B. OR lists A + B but not A \lor B or A \parallel B. Should these alternative boolean algebra notations be listed? What if any ref is required?
Izyt (talk) 18:51, 28 October 2016 (UTC)
replies: text: A \wedge B and A \lor B are, of course, both common, but I have never seen, and cannot find, any usage of A \parallel B to mean "OR" in mathematical notation. Perhaps you were thinking of C language syntax, in which it has a special additional (non-mathematical) meaning?  — Preceding unsigned comment added by 73.47.87.95 (talk) 23:14, 7 November 2016 (UTC)
thread_title:  Boolean algebra notation 

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thread_title:  External links modified 

message: I think this topic is duplicated in the article. I think that the Electronic gates subsection should also be split into physical manufacturing and overview of logic families. AXONOV (talk) ⚑ 15:46, 24 December 2021 (UTC)
thread_title:  Logic families 

message: Hi there folks! Just wanted to open this thread to discuss a small change I made to the table in the Universal logic gates section of the article.
The XOR gate built from NOR gates in the table is the one which, according to the XOR gate article, "offers the advantage of a shorter propagation delay":
Whereas the XNOR gate built from NAND gates in the table was originally the one which, according to the XNOR gate article, actually has more propagation delay:
I figured it would probably be more appropriate - from both the perspective of (a) the table consistently showing the version of the gate with less propagation delay, and (b) symmetry and duality between XNOR/XOR ↔ NAND/NOR - to instead have the table show this version of the XNOR gate built from NAND gates:
I imagine this was just a minor oversight, probably due to the filename of the last image being XNOR from NAND 2.svg, while none of the rest of the filenames have that 2 in them. However, I'm not an electronics expert by any means! So please feel free to revert my edit, if in fact there was some other underlying reason for this asymmetry of which I'm just not aware.
Indnwkybrd (talk) 02:38, 23 October 2023 (UTC)
thread_title:  Universal logic gates-XOR/XNOR asymmetry in the table? 

message: Perhaps the most noteworthy implication of Tesla’s radio-controlled automaton, however, was demonstration of the basic “AND-gate” function that would become an indispensable element of all subsequent electronic and computer logic. His inspiration for this concept reportedly came from studying the work of Victorian biologist and philosopher Herbert Spencer regarding the combined action of two or more nerves in the human body. Tesla’s original implementation employed two sets of transmitters and receivers operating on different radio frequencies to trigger a pair of detector relays. Both these relays had to close at the same time in order to energize a third, which in turn incremented a mechanical escapement driving a rotary switch to decode the command. Tesla’s dual-receiver design provided a relay-based AND-gate function that allowed the contacts of R3 to close only when both R1 and R2 were activated by their respective signals (digitally enhanced from US Patent No. 725,605, awarded 14 April 1903). I feel like Tesla should at least be mentioned as having made an AND gate first. I realize it was not a modern gate, however it did function just like a modern gate. 162.246.112.154 (talk) 17:27, 21 April 2024 (UTC)
replies: text: I'm pretty sure the idea of closing two switches to make something happen predates Tesla and the idea of requiring two things to happen to enable a third thing might well go back to the era of the pyramids. The abstratction of coincidence from a particular application and generaling it as a component of man other systems is the key point here. --Wtshymanski (talk) 23:16, 22 April 2024 (UTC)
thread_title:  Nicola Tesla demonstrated AND gate functioning before anyone named in this article.