Talk:Flip-flop (electronics)

Historical Contributions by Claude Shannon?

It appears the RS flip-flop appears on page 30 of Claude Shannon's 1940 Master's Thesis, as what he calls a "lock-in" circuit:

http://mondrian.die.udec.cl/~mmedina/Clases/SistDig/Shannon%20-%20A%20Symbolic%20Analysis%20of%20Relay%20and%20Switching%20Circuits.pdf

Multi-bit Latch vs single-bit flip-flop. Edge-trigger designation.

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's, and changing the terminology makes reading older material misleading. It's clearer to stick with the original designations:

References

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)Dr. T.S. U.of H. Jan 2019

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)

I agree flip-flop is one bit. I don't think the rest is even vaguely standard. Usually for multi-bit flip-flops the term "register" is used. Hobit (talk) 02:47, 16 September 2021 (UTC)

Q and Q-bar do not switch exactly simultaneously

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)

Latches vs Flip-flops again

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)

I agree. Lambtron talk 16:31, 22 June 2026 (UTC)

Confusing sentence in lede

When used in a finite state machine, the output and next state depend not only on its current input, but also on its current state (and hence, previous inputs).

The above sentence is a confusing mix of FSMs, FFs and latches. The output of a FF (its state) does not depend on its inputs, and its next state depends solely on its inputs. The output of a latch (its state) and its next state are functions of both its state and inputs. The output of a Moore FSM is strictly a function of its state, and a Mealy FSM of both its inputs and state.

IMO, the sentence should be reworked to avoid conflating these topics, or deleted altogether. It's possible the latter may be the best course of action as this article is about FFs/latches, not FSMs. Lambtron talk 16:28, 22 June 2026 (UTC)