Talk:Flip-flop (electronics)

message: The correct, or at least "electronics industry-standard" terminology is "flip-flop," that is, with the hyphen. — Preceding unsigned comment added by Rcingham (talk • contribs) 03:07, 5 September 2002 (UTC)
replies: text: Chambers Science and Technology Dictionary and the OED agree with you.  -- Heron —Preceding undated comment added 18:09, 6 September 2002 (UTC)
replies: text: I now replaced "flip flop" with "flip-flop" in the whole text. Should the page also be moved to "flip-flop"? We would need to first delete the redirect in the other direction in that case. Colin Marquardt 13:45, 28 Aug 2003 (UTC)
replies: text: Well, I did a cut and paste move.  I couldn't find a page where I could request a move or delete the redirect.  172.196.215.224 —Preceding undated comment added 01:03, 20 September 2004 (UTC)
thread_title:  Flip flop or flip-flop 

message: This article does not explain the difference between flip-flops which are level sensitive (e.g. latches), master/slave, or edge sensitive.
Anon April 26, 2005
:Moreover, it's totally incorrect to structure flip-flop by timing type and then by functioning type, 'cause these two are different types of classification. E.g. an RS flip-flop can be both level- and edge-triggered.
:We should first consider functioning types and then place a chapter "Level-triggered and edge-triggered flip-flops"
:btw i'm going to handle this when it's summer and i have some spare time :^) Ivan Pozdeev 15:08, 25 May 2006 (UTC)
thread_title:  Different clocking types 

message: A recent Slashdot post mentioned the possibility that J-K flip flops were not actually named after Jack Kilby.  Does anyone buy this?
::His name will forever be engraved in the J-K flip-flop.
:This is probably an urban legend. More likely it was the initials of John J. Kardash [google.com], who in the 1950's arbitrarily used his initials on these pins on his blueprints, and it stuck.
(quoted from Slashdot post #12877710; see the Google Answers result for more information) - McCart42 (talk) 17:52, 2005 Jun 22 (UTC)
This should be fixed here as well as the kilby page and the Integrated circuits page. By fixed I mean either removed or finding some fairly reputable source for the information and citing it. Danny31415 4 July 2005 10:37 (UTC)
Presumably the above was written before the note about Dr. Nelson was added to the flip-flops page. I was at Hughes Aircraft at the same time as Dr. Nelson, and can confirm the origin there of the J-K flip-flop. Neither Kilby nor Kardash had anything to do with it.MontyPh 18:05, 10 January 2007 (UTC)
replies: text: Oddly enough, John Kardash did invent a J-K flip-flip.  He has a patent on it, filed in 1965.  In it, he says "One type of bistable circuit which is frequently used is known as 'J-K flip-flop'."  He is not claiming to have invented the type, just that circuit.  And thanks to Monty Phister, I now have an autographed copy of his 1958 textbook Logical Design of Digital Computers (he signed for me the copy of the book that my dad studied it from in 1959, to supplement the other copy I found) in which the 'J-K flip-flop' is discussed as "...has the properties of an R-S memory element, except that the combination J = K = 1 is allowed, and causes the circuit to change state...".  The book mentions R. G. Nelson (probably not the Nelson he refers to above) on page 74, and discusses his logic simplification method, but doesn't say anything about the origin of the flip-flop names; I think we'll have to take Monty's word for it.  Dicklyon (talk) 05:22, 24 October 2011 (UTC)

text: "Each flip-flop or bistable multivibrator includes two input terminals, hereinafter termed the j-input and the k-input terminals, respectively, and two output terminals for producing complementary bivalued electrical output signals hereinafter termed Q and Qbar, respectively. Signals applied separately to the j-input and k-input terminals set the flip-flop to conduction states corresponding to the binary values one and zero, respectively, while signals applied simultaneously to both input terminals trigger or change the conduction state of the flip-flop."
Given that he's using the input names j and k, and talking about the function we call a JK flip-flop, it seems fair to credit him with the name.  Dicklyon (talk) 05:56, 24 October 2011 (UTC)

text: Could it be that E.C. Nelson just didn't want to start at A? (Maybe he was using A-I regularly for other pins on something he was interfacing with the JK flip-flops and didn't want to confuse them, so he felt like starting this one at J, and K is the next letter... -- or maybe didn't want his flip-flops confused with others, since the function was different, etc...) BrainSlugs83 (talk) 08:08, 19 September 2012 (UTC)
thread_title:  J-K flip flop naming a myth? 

message: Eldred C. Nelson, inventor, US 2850566 "High-Speed Printing System", filed Sep 8, 1953, issued Sep 2, 1958, assigned to Hughes Aircraft Company.  In column 13:
:"Each flip-flop or bistable multivibrator includes two input terminals, hereinafter termed the j-input and the k-input terminals, respectively, and two output terminals for producing complementary bivalued electrical output signals hereinafter termed Q and Qbar, respectively. Signals applied separately to the j-input and k-input terminals set the flip-flop to conduction states corresponding to the binary values one and zero, respectively, while signals applied simultaneously to both input terminals trigger or change the conduction state of the flip-flop."
Given that he's using the input names j and k, and talking about the function we call a JK flip-flop, it seems fair to credit him with the name.  Dicklyon (talk) 05:56, 24 October 2011 (UTC)
replies: text: Could it be that E.C. Nelson just didn't want to start at A? (Maybe he was using A-I regularly for other pins on something he was interfacing with the JK flip-flops and didn't want to confuse them, so he felt like starting this one at J, and K is the next letter... -- or maybe didn't want his flip-flops confused with others, since the function was different, etc...) BrainSlugs83 (talk) 08:08, 19 September 2012 (UTC)
thread_title: Found: Eldred C. Nelson 1953 patent filing

message: The JK flip-flop was widely used in the 1970's when small scale integrated circuits with flop-flops were common, and many different variants were available in TTL ICs. The advantage was that you could make counters etc. with fewer ICs. But today JK flip-flops have largely been replaced by D flip-flops because the math is simpler and they are suitable for FPGAs etc. However, I can't find any reference for this. Some textbooks are out of touch with modern electronics and still treat the JK flip-flop as important, which I think is wrong. Agnerf (talk) 11:57, 21 August 2018 (UTC)
thread_title:  Is JK flip-flop obsolete? 

message: Flip-Flop is not a bistable multivibrator. It can implement one with peripheral components, but it is not even its main use. I would change the definition to the following:
In electronics and digital circuits, the flip-flop is a pulsed digital circuit capable of serving as a one-bit memory.
--Michagal 15:14, 23 May 2006 (UTC)
replies: text: I disagree, the basic RS flip flop (from which afaict all the other variants developed) is simply a bistable multivibrator implemented using logic gates rather than discrete components. Plugwash 17:58, 23 May 2006 (UTC)
replies: text:  I think the problem is that the original commenter didn't look up with a bistable multivibrator was. People don't understand that a bistable multivibrator has two stable states. They see "vibrator" and think it oscillates (i.e., an astable multivibrator). A flip flop (in fact, a latch) is certainly a bistable multivibrator. —TedPavlic (talk/contrib/@) 21:19, 16 July 2009 (UTC)
thread_title: Flip-Flop definition

message: The diagram does not seem to be right. If the clock is zero then both outputs are 1. A correct implementation can be found e.g. at http://wearcam.org/ece385/lectureflipflops/flipflops/ , or more exactly http://wearcam.org/ece385/lectureflipflops/flipflops/fig5a.gif
I agree -- the picture of the D flip-flop is wrong (for the reasons mentioned above).  The picture should be removed (and preferably corrected). -- Milom 00:16, 19 September 2006 (UTC)
thread_title:  Circuit diagram in D-Type Transparent Latch.svg 

message: Regarding the graphic in Master-slave D flip-flop, the double NOT logic from C is quite unnecessary -- it's easier just to branch C and not one side and leave the other side normal.  St.isaac 02:15, 1 March 2007 (UTC)
replies: text: Master-Slave DFF has two images: the complete implementation using logic gates and partial schematic using two D-latches. I feel that this is redundant and propose to remove the partial implementation (image on the left) and to change the central image to reflect the fact that it is composed of two D-latches with a NOT in between. Michagal 08:50, 29 March 2007 (UTC)
thread_title:  Master-slave D flip-flop 

message: Is Q an abbreviation for something? --Abdull 15:01, 6 March 2007 (UTC)
replies: text: Welcome to the world of digital electronics! The real answer is nobody knows. Just like how nobody knows why Vcc and Vss are often used for power connections. They are merely standards that have been adopted because certain papers whom used the values become popular many many years ago.--Dacium 06:54, 5 April 2007 (UTC)
replies: text: That is not exactly true. Vcc is for collector power supply. The "c" is doubled to differentiate it from the voltage on the collector itself, Vc. Vss is used in FET transistors, "s" is for source.Michagal 13:14, 5 April 2007 (UTC)
replies: text: More specifically, CC is Common Collector—the bus tied to every collector in a purely npn circuit (not to be confused with a common collector amplifier). The other abbreviations (Vee,Vss,Vdd) were consistent and have stuck for historical reasons. Regarding Q, I don't have any sources, but I'm guessing that it was used because it's the letter before RS. That is, QRS is alphabetical (just as JK is). Additionally, Q is often used to represent the charge (or even energy) in a circuit. A flip-flop doesn't store its memory in charge (it uses positive feedback to create an unstable node that drives trajectories to its rails), but the net effect is very similar to DRAM. That being said, I'm pretty sure the QRS explanation is correct. —TedPavlic (talk) 14:54, 9 February 2009 (UTC)
replies: text: In my many years of using "VCC" I never encountered that explanation.  Do you have a source for it?  Dicklyon (talk) 16:27, 9 February 2009 (UTC)
replies: text:  Does Wikipedia count as a source?IC_power_supply_pin --71.182.247.251 (talk) 05:45, 5 February 2010 (UTC)
replies: text: Never! 81.129.194.183 (talk) 12:40, 16 April 2021 (UTC)
thread_title:  Q 

message: Note that it is just to store data temporarily, this type of memory formed by the flipflops is volatile which means that it depends on voltage —The preceding unsigned comment was added by 202.83.169.218 (talk) 06:14, 3 May 2007 (UTC)
thread_title:  Volatile memory 

message: Under
"Timing and metastability", this line
"In many cases, metastability in flip-flops can be avoided by ensuring that the data and control inputs are held constant for specified periods before and after the clock pulse, called the setup time (tsu) and the hold time (th) respectively." is a bit unclear and ambiguous. I first thought tsu and th was the time the flip-flop waited before it accepted any input. So "the data and control inputs" refers to _external_ drives? Should the sentence be reformulated?
129.241.203.41 12:14, 11 October 2007 (UTC)
replies: text: I agree. The metastability can be avoided in ``all cases``, not  ``in many cases`` by observing Ts and Th. The definition of tsu and th is the specified time flip-flop's input has to remain '0' or '1' before and after clock's active edge. Michagal 12:32, 11 October 2007 (UTC)
thread_title:  Timing and metastability 

message: I was wondering how the picture below is positive edge triggered. When the signal changes from high to low the data is stored, not when it changes from low to high. Is the clock signal inverted? If so, it should be stated that the picture is negative edge triggered.
No, the diagram is fine. Note that when the clock signal is low, both the lines leading out of the first stage (the four gates on the left) into the second stage end up high, regardless of whether D is high or low. And the second stage is a SR latch which is set/reset by sending one of its inputs LOW, so nothing changes when both are high. Only when the clock switches to high with the data input held stable do the lines to the output latch go low (only one of the lines), as is necessary for it to change. (it's important for D to stay at one value during the transition, otherwise there are logic races and the results are unpredictable)  88.107.18.45 (talk) 06:57, 29 December 2008 (UTC)
thread_title:  Edge-triggered D flip-flop 

message: The article does not explain the historical bias/suitability of NAND gates over AND, OR, XOR, NOR and XNOR to implement flip-flops.Anwar (talk) 17:26, 22 May 2008 (UTC)
thread_title:  Gate bias 

message: Maybe is should be noted, that most flip-flops also have asyncronous preset and clear possibilities,have enable, and if disabled both output go HiZ. Bg665 (talk) 20:10, 21 October 2008 (UTC)
thread_title:  Practical considerations 

message: Hello,
At the beginning of the "JK flip-flop" section it reads:
The JK flip-flop augments the behavior of the SR flip-flop (J=Set, K=Reset) by interpreting the S = R = 1 condition as a "flip" or toggle command.
This is a JK flip-flop, so shouldn't it say:
The JK flip-flop augments the behavior of the SR flip-flop (J=Set, K=Reset) by interpreting the J = K = 1 condition as a "flip" or toggle command.
This is an important distinction as it would confuse me to see S = R = 1 in the introduction sentence and then to read the Characteristic table, which has J = K = 1 for the flip.
I was too nervous to just go ahead and change it myself.  Does anyone else agree that it needs to be changed?
fogus (talk) 20:27, 3 December 2008 (UTC)
replies: text: It makes sense to use S and R in that sentence.  It is making a comparison with an SR flip-flop so SR terms should be used.  If you jump straight to J and K the logic of the comparison becomes less obvious, and arguably wouldn't make sense at all - the sentence begins with an SR flip-flop and modifies it to be a JK flip-flop.  Using JK nomenclature to begin with would fuzzy the fact that we start with an SR type. CrispMuncher (talk) 22:50, 3 December 2008 (UTC)
thread_title:  JK flip-flop mistake? 

message: It would be nice if the D flip flop spoke of reset signal behavior or had it in the truth table. Is reset read on clock edge? Is it async?  —Preceding unsigned comment added by Brandon.irwin (talk • contribs) 01:42, 12 December 2009 (UTC)
replies: text: Typically Reset is read asynchronously but it dosen't have to be.  Rester might be better explained with a cirucit level diagram, perhaps I'll add one...  Guerberj (talk) 05:46, 13 December 2009 (UTC)
thread_title:  D flip flop missing reset behavior 

message: I think there's a little discrepancy in the JK flip-flop section. The timing diagram is for a positive edge triggered JK flip-flop, and the article states "The flip-flop is positive-edge triggered (rising clock pulse) as seen in the timing diagram." This is true, but the circuit symbol diagram shows a negative edge triggered flip-flop(clock connection arrow pointing inwards) which could cause some confusion among readers.130.209.241.193 (talk) 09:13, 20 January 2010 (UTC)
thread_title:  JK flip-flop 

message: I'm not used to editing wiki and all so ill apologize for not signing this up ahead,
Scripted a small flipflop in stl, for anyone that wants to write one, or has to write one, instead of using an LAD or FDB.
Every x value not preceeded by an comment should be in the same byte range pick one to your own liking
I have used the 22th byte range in two or three places, but thats changable.
      A(    
      O     Q      x.7
      O     Q      x.4
      )     
      NOT   
      =     Q      x.0
      A     Q      x.0
      =     L     22.0
      A(    
      A(    
      A(    
      A(    
      O     L     22.0
      ON    I      x.0
  // The above is your input, every input is the same ofcourse.
      )     
      NOT   
      =     Q      x.1
      A     Q      x.1
      O     Q      x.6
      )     
      NOT   
      =     Q      x.2
      A     Q      x.2
      O     I      x.0
  // The above is your input, every input is the same ofcourse.
      )     
      NOT   
      =     Q      x.3
      A     Q      x.3
      O     Q      x.0
      )     
      NOT   
      =     Q      x.4
      A     Q      x.4
      =     L     22.1
      A(    
      A(    
      A(    
      O     L     22.1
      ON    I      x.0
  // The above is your input, every input is the same ofcourse.
      )     
      NOT   
      =     Q      x.5
      A     Q      x.5
      O     Q      x.2
      )     
      NOT   
      =     Q      x.6
      A     Q      x.6
      O     I      x.0
  // The above is your input, every input is the same ofcourse.
      )     
      NOT   
      =     Q      x.7
      A     Q      x.7
      =     Q      x.7
      A     L     22.1
      BLD   102
      =     Q      x.0
  // replace x with an output digit.
      A     L     22.0
      BLD   102
      =     Q      x.1
  // replace x with an output digit.
A few minor mistakes, since i took it straight from the program im running, but i fixed   them. 217.166.79.130 (talk) 09:44, 10 February 2010 (UTC)
thread_title:  STL Scripting 

message: It schould be "Rising Eadge or 1" right?
http://web.cs.mun.ca/~paul/cs3724/material/web/notes/node13.html
http://www.elektronik-kompendium.de/sites/dig/0210031.htm (German)
sorry for bad english, don't want to be unpolite -- please help  —Preceding unsigned comment added by 194.95.66.1 (talk) 21:54, 3 May 2010 (UTC)
thread_title:  D flip-flop - Logic Table 

message: This section has a problem with the last paragraph/block, which doesn't match the figure (4-bit shift register), so it doesn't make sense:
:The above circuit shifts the contents of the register to the right, one bit position on each active transition of the clock. The input X is shifted into the leftmost bit position.
There is no x input in the figure, and the bits look like they're shifting rightward, which is not necessarily the leftmost bit position.  —Preceding unsigned comment added by 76.221.133.164 (talk) 07:22, 22 November 2010 (UTC)
thread_title:  D (Data) flip-flop 

message: What happened to the section on Chaos?  I'm gona go ahead and restore it.
--Aminhungryboy (talk) 17:40, 29 November 2010 (UTC)
replies: text: It is too abstract for this essential and concrete page about flip-flops. Please, place this data on a more appropriate page. Circuit dreamer (talk, contribs, email) 17:46, 29 November 2010 (UTC)
replies: text: I see what your saying.  I'm not the most experience wikipedia user.  Do you know a page in which I may insert this? --Aminhungryboy (talk) 17:51, 29 November 2010 (UTC)
replies: text: Maybe, as an application of a Chaos theory or Chua's circuit? Circuit dreamer (talk, contribs, email) 18:25, 29 November 2010 (UTC)
replies: text: Hmm, Chaos theory page seems like a good idea.  The stuff on Chua's circuit was just a bit of a background on simple chaotic circuits.  I'll move it to the chaos theory page once I get the time.  Thanks.  --Aminhungryboy (talk) 19:57, 2 December 2010 (UTC)
thread_title:  Chaos 

message: I have moved the introductory part of this article to Latch and rearranged the two articles guided by the considerations below.
* Flip-flop and latch are not the same; so, they deserve separate pages (as it is).
* Flip-flop and latch are closely related; so, the two pages have to be closely related as well.
* The latch precedes chronologically the flip-flop.
* Eccles and Jordan have invented a latch, not a flip-flop; so, the data about their patent have to be placed on Latch.
* The fundamental bistable circuit is simpler than a latch and the latch is simpler than a flip-flop; so, the fundamental bistable circuit has to be inserted in the introductory part of Latch.
* The flip-flop is based on the latch; it is built by one or more latches; so, Flip-flop is a continuation of Latch.
I would be glad if you appreciate my efforts to solve the problems connected with the distribution of the contents between the two pages. Circuit dreamer (talk, contribs, email) 22:53, 1 December 2010 (UTC)
replies: text: OK, I've made an effort to help, by resetting to a less wrong state and starting a formal merge discussion.  Your assertion that "Eccles and Jordan have invented a latch, not a flip-flop" is pure revisionism, not supported by sources; not a good basis for your way of fixing the problem.  I think the merge that Zen-In suggested will make it easier to get it right, with flip-flop as the broad category, and things like transparent latches and clocked D flip-flops as subtypes.  Dicklyon (talk) 06:15, 4 December 2010 (UTC)

text: I think I support the notion of merging down to a single article.  The distinction between latches and flip-flops is largely academic, and certainly ill-defined.  Oli Filth(talk|contribs) 23:55, 3 December 2010 (UTC)

text: tentative support for merge. See Dicklyon's comments from a year ago. Transistor bistable multivibrators were called FFs. Today's distinction is more tied to choice of clocking scheme (which driven by underlying technology). Tentative because merge may cause bloat. Glrx (talk) 03:57, 4 December 2010 (UTC)
replies: text: There's not so much there that the result will be huge.  We may even get some de-bloating in the merge.  I just looked at latch (electronics) and saw the "Latch schematics from the Eccles and Jordan patent filed 1918" which is just absurd.  In Google book search, there are 381 hits for "Eccles Jordan flip flop", but nothing at all for "Eccles Jordan latch".  This revisionism of Circuit Dreamer based on what he thinks things should be called is just annoying. Dicklyon (talk) 06:03, 4 December 2010 (UTC)
thread_title:  Rearranging "Flip-flop" and "Latch" articles 

message: There is no need to develop a new taxonomy of latches and flip-flops.  In fact it might be a good idea to merge the two pages since there is  lot of cross-over between the two.  There are clocked latches and flip-flops can be used asynchronously.   It is better to have an accurately written article instead of trying to write the articles in such a way as to justify having two separate pages as C-D wants.   But these same opinions have been voiced many times before by myself and others for a couple of years.  At this point I think the only solution is to file an ani action and see how the chips fall.  Zen-in (talk) 05:36, 2 December 2010 (UTC)
thread_title:  No new Science here 

message: I don't see support for Circuit Dreamer's wholesale redefinition and reorganization of the article since Nov. 28 or so, and propose that we take it back again to where it was before, and discuss changes before committing to something so major.  To me, the old broad definition makes a lot more sense than the new narrow one.  Perhaps as others have suggested, merging latch in here will also make it easier to start with the broad definition and then define narrower usages.  Dicklyon (talk) 23:27, 3 December 2010 (UTC)
replies: text: I think I support the notion of merging down to a single article.  The distinction between latches and flip-flops is largely academic, and certainly ill-defined.  Oli Filth(talk|contribs) 23:55, 3 December 2010 (UTC)

text: tentative support for merge. See Dicklyon's comments from a year ago. Transistor bistable multivibrators were called FFs. Today's distinction is more tied to choice of clocking scheme (which driven by underlying technology). Tentative because merge may cause bloat. Glrx (talk) 03:57, 4 December 2010 (UTC)
replies: text: There's not so much there that the result will be huge.  We may even get some de-bloating in the merge.  I just looked at latch (electronics) and saw the "Latch schematics from the Eccles and Jordan patent filed 1918" which is just absurd.  In Google book search, there are 381 hits for "Eccles Jordan flip flop", but nothing at all for "Eccles Jordan latch".  This revisionism of Circuit Dreamer based on what he thinks things should be called is just annoying. Dicklyon (talk) 06:03, 4 December 2010 (UTC)
thread_title:  Why the big change? 

message: : Merge from Latch (electronics) into Flip-flop (electronics)
I've added merge proposal tags and opened this discussion, in support of the idea floated above.  A latch is just a type of flip-flop, in modern terminology, and can easily be treated with sections in the main article, which will remove much of the imagined problem that is being addressed wrongly by trying to give a narrower definition to flip-flop.  Dicklyon (talk) 06:13, 4 December 2010 (UTC)
replies: text: There were three possible solutions of the problem: two separate pages; one big page; one main page and a few subpages. As I can see, you have chosen the second one. I appreciate your efforts to improve the article and will await you to finish your edits. For now, I would like only to note that a T flip-flop made from a synchronous edge-triggered D flip-flop by connecting its inverted output to its D input is exactly an asynchronous circuit. There is a clever trick in this circuit solution: the genuine D input is used as an internal input for implementing a delayed (with one cycle) "negative feedback" and the clock input is used as a new circuit input. As a result, the circuit has lost the clock input; it has only one asynchronous input. Circuit dreamer (talk, contribs, email) 16:35, 5 December 2010 (UTC)
replies: text: I suppose by some definitions you can call it asynchronous.  But it's also a device commonly used in synchronous clocked systems to make an alternating 0-1 signal.  The output changes after the after clock edge, just as with other synchronous flip-flops; it integrates perfectly with the others, since it is one.  If you want to use it as an element in an async circuit, say by clocking it with a data signal, you can do that, too.  Dicklyon (talk) 20:22, 5 December 2010 (UTC)
replies: text: It can be used in synchronous clocked systems but it is an asynchronous T flip-flop. If we consider it as a D flip-flop with D input connected to some output (in this specific case, to its own inverted output) and C input connected to the clock, it is a synchronous D flip-flop having two inputs (data and clock). But in this circuit the D flip-flop is only a component used to build a T flip-flop having only one input (toggle). So, the whole circuit is an asynchronous T flip-flop that can be used wherever. Circuit dreamer (talk, contribs, email) 21:33, 5 December 2010 (UTC)

text: The fundamental problem is that the flip-flop article is built around the most broad and generic definition of the term, and you can't just change that without consensus.  The Eccles Jordan trigger circuit was called a flip-flop long before the notion of a "latch" was invented for some kinds of flip flops.  You can still represent the more modern distinctions of usage in the article, but you can't use that to rewrite history.  Dicklyon (talk) 19:19, 4 December 2010 (UTC)
replies: text: Well, another solution of the problem is to add a small introductory text in the beginning of flip-flop page (e.g., in History or/and Implementation section) where to make the connection with the simpler latches (to remind the Latch page). This text will serve as a summary about latches. Circuit dreamer (talk, contribs, email) 21:50, 4 December 2010 (UTC)
thread_title:  Merge proposal 

message: I am glad to see that you have arrived at the decision to merge the two pages since it actually was my idea. As you can see, I have only distributed the existing contents between the two pages and structured them to prepare the ground for future merging (if we decide to do it). Now the two pages are tidy, well structured and intelligible. The fundamental idea is revealed in the beginning of Latch and then its evolution is shown in a logical succession: basic bistable circuit -> "direct" RS latches -> gated latches -> ... then it continues in Flip-flop ... -> edge-triggered flip-flops -> pulse-triggered flip-flops. Now, we have only to insert the contents of latch page in the beginning of flip-flop one and to generalize the lede to obtain the desired common page (latch should be redirected to flip-flop). 
Of course, it is obvious for everyone that now latches and flip-flops are unnaturally separated in these two pages; they are only different stages of the humble Eccles-Jordan bistable circuit in the stairs of its evolution. But we have somehow to distribute the content about all these memory circuits into separate pages because it is too large for one page. So, I have started with the existing organization - each circuit in its own page, subordinating the latch to flip-flop page. But this is only one possible (not so bad) way of presentation.
The alternative approach (suggested above) can be realized as a set of one main and a few subordinated pages. The main flip-flop article should contain only essential data about fundamental bistable circuit and to show (in the succession above) the typical flip-flop implementations. The specific circuit solutions should be shown in the separate subpages. Thus the main page will reveal the fundamental ideas behind flip-flops and the subpages will show their specific implementations (see for example op-amp applications). 
I hope you realize how arduous this undertaking is. It can be implemented by creative, thinking and conscientious wikipedians behaving positively; but I do not see such persons here. Instead, I see exactly the opposite - wikipedians that brutally blank, remove and revert without any comments large blocks of text revealing the fundamental ideas behind circuits...
I was rather impressed by wikipedians (some of them anonymous) having a talk more than a year ago. There are valuable thoughts, generalizations and philosophy in their discussions that can be inserted in the articles. Such kind of people can implement this ambiguous undertaking... but they keep silence for now... Maybe new people will join this undertaking... Till then the reorganized articles about latches and flip-flops can serve as a better basis for further improving (merging, splitting, whatever...) than the previous eclectic "mess". Circuit dreamer (talk, contribs, email) 11:16, 4 December 2010 (UTC)
replies: text: The fundamental problem is that the flip-flop article is built around the most broad and generic definition of the term, and you can't just change that without consensus.  The Eccles Jordan trigger circuit was called a flip-flop long before the notion of a "latch" was invented for some kinds of flip flops.  You can still represent the more modern distinctions of usage in the article, but you can't use that to rewrite history.  Dicklyon (talk) 19:19, 4 December 2010 (UTC)
replies: text: Well, another solution of the problem is to add a small introductory text in the beginning of flip-flop page (e.g., in History or/and Implementation section) where to make the connection with the simpler latches (to remind the Latch page). This text will serve as a summary about latches. Circuit dreamer (talk, contribs, email) 21:50, 4 December 2010 (UTC)
thread_title:  The "mess" is restored again... 

message: I'm going to remove the following section from the article because there are no inline sources for it and it is unclear to the point of being useless. Before this information can be useful, several questions must be answered.
* What does it mean when the clock input is "strobed?" Does it mean that the clock is on its rising edge, off, or on?
* What happens when the clock input is not "strobed?"
* What is the relationship between Qnext and Qprev in terms of time?
* Does "If the T input is low, it holds the previous value." apply when the clock input is "strobed" or does that statement apply always?
Also, the ending sentence of this section is redundant with the other sections of this article so it is also being removed. --Sbluen (talk) 05:38, 1 January 2011 (UTC)
thread_title:  removing section: Gated T Latch 

message: I think I'd prefer a neatly hand-drawn sketch, scanned, instead of "ASCII art".  This isn't Usenet 1983, and the ASCII picture takes too much interpretation to make it useful (and I suspect is missing some lines, too). Will anyone beat me to fixing it? --Wtshymanski (talk) 19:24, 5 January 2011 (UTC)
thread_title: Earle latch needs a diagram

message: I think there's an error under the heading 'Gated SR latch'. This seems wrong for the gates mentioned: "The extra gates further invert the inputs so the simple (not)SR latch becomes a gated SR latch (and a simple SR latch would transform into a gated (not)SR latch with inverted enable)." I believe that using ANDs on an SR latch turns it into a gated SR latch, and NANDs for a (not)SR latch turn it into a gated (not)SR latch. What it should say is that ANDs on a (not)SR latch and NANDs on an SR latch invert them into gated latches. I think the article says it backwards. But I don't have electronics experience, so someone tell me if I'm wrong. LieAfterLie (talk) 07:18, 13 January 2011 (UTC)
thread_title:  'Gated SR latch' error 

message: I made some small changes to the article, primarily to maintain consistency in the notation and to parallel ideas between implementations. Here are some comments I would like to make.
1. The FFs should be listed in the oder RS, JK, D and T because JK is a modified version of RS. Keeping the RS, JK, D and T sequence, will help the reader in understanding the FF.
2. Tables are not consistent in their design. They should all be standardized to look the same way (compare SR NOR latch and JK latch).
3. The description in the image for the Gated SR NAND D latch is unnecessary and inconsistent with the rest of the images. D, E, Q and Q should be removed or placed in the text.
4. The E/C signal for the SR and D latches should be reduced to E alone, first of all for consistency with the FF symbols, secondly because E is the most general idea and it replaces C (C for CLK). The last sentence for the D section should also be fixed.
5. The Q column in the gated D latch table is ridiculously unnecessary. It is well understood that Q is the complement of Q. Take it off please.
6. I am not sure what the end of this sentence implies: "Whenever the clock pulses, the value of Qnext is D and Qprev otherwise." I either don't understand the sentence or the sentence needs to be rewritten.
7. In the second table for the D FF, the clock should be shown as CLK or C and not >. > is only a symbol, not a name for a signal. This happens in other tables.
8. "A more efficient way to make a D flip-flop is not so easy to understand, but it works the same way." This sentence needs to be rewritten.
9. The table for the T FF shows characteristic and excitation tables. I don't see why others flip flop should not be treated the same way. All flip-flops should have characteristic and excitation tables (D FF included).
10. "However fast we make the device, there is always the possibility that the input events will be so close together that it cannot detect which one happened first." This sentence is horrible. The use of "we" instead of the third person is not elegant and the sentence needs a revision.
11. Why do symbols have to be ridiculously gigantic?
This article is fairly decent but it could definitely be improved.
ICE77 (talk) 08:03, 18 March 2011 (UTC)
replies: text: By all means, standardize. If someone disagrees, they should change all of the similar tables/graphics to another format, keeping the standardized view. As for copyedits, much of this article, like other articles, are written in sub-standard prose; again, by all means, change it. I also think the symbols/graphics are too large. I am not even reading these sentences you point out, BTW. Just change them if the edits are non-controversial. — Preceding unsigned comment added by Int21h (talk • contribs) 20:10, 15 April 2011 (UTC)
thread_title:  Corrections and comments 

message: Aren't they the same thing, so why does th article keep flip flopping between the 2?  —Preceding unsigned comment added by 129.97.120.139 (talk) 21:53, 10 April 2011 (UTC)
replies: text: Because they're equivalent, and the article is astable.  Dicklyon (talk) 05:00, 24 October 2011 (UTC)
thread_title:  SR Or RS 

message: I am proposing we add a Synthesis section with Verilog examples from that article. I propose Verilog (IEEE 1364) instead of VHDL (IEEE 1076 and 1164) or SystemVerilog (IEEE 1800) because it is simpler than VHDL, having a C-like syntax, and more widespread and simpler than SystemVerilog, which is a superset of Verilog-2005 with features not really applicable to flip-flops and latches. See the Verilog article for the examples. It is less important than the sections already here, and I am not sure putting the examples into the subsections for each type will not confuse the reader. Int21h (talk) 20:06, 15 April 2011 (UTC)
replies: text: Oppose. The article is about the hardware and not about Verilog or VHDL. Glrx (talk) 00:26, 16 April 2011 (UTC)

text: Just refer to the Verilog article for how flip-flops are represented in an HDL.  Dicklyon (talk) 00:46, 16 April 2011 (UTC)
thread_title:  Synthesis section 

message: Some old page history that used to be at the title "Flip-flop (electronics)" can now be found at Talk:Flip-flop (electronics)/Old history. Graham87 00:41, 24 June 2011 (UTC)
thread_title:  Old page history 

message: The comments about the dynamic flip flop raises issues about other memory devices. Should the article mention the 3T and 1T DRAM cells? In early computers, tubes were expensive; IIRC, Atanasoff considered using a capacitor for storage. Glrx (talk) 19:43, 1 November 2011 (UTC)
replies: text: I don't think these dynamic cells have ever been called flip-flops; and they are not used like flip-flops.  The clocked dynamic flip-flops are used exactly like flip-flops in synchronous logic, and they are referred to as flip-flops, which is why they are included.  Dicklyon (talk) 21:20, 1 November 2011 (UTC)
thread_title:  Dynamic FF 

message: Any chance of slowing down the animation, so that the transition between the stable states can be followed?  — Preceding unsigned comment added by 91.125.194.28 (talk) 22:47, 13 February 2013 (UTC)
thread_title:  Slow down top animation ("R-S mk2.gif")? 

message: A couple more external links just got added today, prompting me to check the whole list.  To me, they all look like low-quality junk.  Does anyone have an objection if I remove them all?  Msnicki (talk) 05:27, 4 February 2017 (UTC)
thread_title:  Low-quality external links 

message: Anyone care to explain how this circuit functions / provide sources ? It comes without any explanations, and hand analysis + simulations don't show it working. Besides it doesn't have any feedback loop, so I fail to see how it could act as a sequential system ? NoahhaoN (talk) 01:37, 18 May 2017 (UTC)
replies: text: I agree. It looks wrong. It has no feedback so the only way it can save a bit value is by charging a stray capacitor, but I can't see where that would be. A correct CMOS D flip-flop is shown at http://www.learnabout-electronics.org/Digital/dig55.php figure 5.5.2. I think the illustration must be changed and the text should emphasize that it is specific for CMOS technology - it doesn't work with bipolar transistors. Agnerf (talk) 11:42, 21 August 2018 (UTC)
replies: text: I moved it into the dynamic section.  Dicklyon (talk) 23:56, 5 January 2019 (UTC)
thread_title:  CMOS implementation of an edge-triggered D-flip flop 

message: Recent edits show a problem at Flip-flop (electronics)#SR NOR latch which currently ends with:
:Alternatively, the restricted combination can be made to toggle the output. The result is the JK latch.
:Characteristic: Q+ = R'Q + R'S or Q+ = R'(Q + S).
I believe R' means not R = , and Q+ refers to what is called Qnext in the table. That is,
:Characteristic: Q+ = Q + S or Q+ = (Q + S).
That seems wrong; it should be:
:Characteristic: Q+ = S + Q.
Thoughts? Johnuniq (talk) 23:22, 4 November 2017 (UTC)
thread_title:  SR NOR latch 

message: The term flip-flop is not consistently used to differentiate edge triggered from level triggered devices, but the term flip-flop has always consistently referred to a single bit storage element constructed from logic gates. The term latch has historically been used for multiple bit storage elements that share a trigger. The terms edge triggered and level triggered are clear and unambiguous and should be used to differentiate between the triggering mechanism, rather than trying to use flip-flop for that purpose. "Level triggered flip-flop" can be found in  textbooks from the 70'sRoth, Charles, Fundamentals of Logic Design, 2ed. West 1979., and changing the terminology makes reading older material misleading. It's clearer to stick with the original designations:
Edge triggered flip-flops
* clearly a single bit
* clearly edge triggered
Level triggered flip-flops
* clearly a single bit
* clearly level triggered
Edge triggered Latches
* clearly edge triggered
* may store multiple bits
Level triggered Latches
* clearly level triggered
* may store multiple bits
Use of this terminology is historically consistent and unambiguous. Also, because multi-bit latches exist, they should have their own page. The internals of storage of each bit should direct to the flip-flop page.
132.160.49.90 (talk) 22:41, 5 January 2019 (UTC)
replies: text: I support this suggestion.  At least parts of it agree with the 2013 update of the referenced text. Dicklyon (talk) 23:41, 5 January 2019 (UTC)
thread_title:  Multi-bit Latch vs single-bit flip-flop. Edge-trigger designation.  

message: In latches and flip flops Q and Qbar do not change signal exactly simultaneously.
Should this fact be added to the article, together with it's consequences?
Jacob.Koot (talk) 11:12, 15 May 2021 (UTC)
thread_title:  Q and Q-bar do not switch exactly simultaneously 

message: I'd like to clean up this issue.  As noted above, the interchangeable use of "latch" and "flip-flop" hasn't been standard for probably decades.  If needed we can have a formal RfC, but I thought just see if we can agree to use latch for the transparent/asynchronous devices and flip-flop for the synchronous edge-triggered devices.  Objections? Hobit (talk) 02:46, 16 September 2021 (UTC)
thread_title:  Latches vs Flip-flops again