JK FLIP FLOP

The J-K flip-flop



Another variation on a theme of bistable multivibrators is the J-K flip-flop. Essentially, this is a modified version of an S-R flip-flop with no "invalid" or "illegal" output state. Look closely at the following diagram to see how this is accomplished:


What used to be the S and R inputs are now called the J and K inputs, respectively. The old two-input AND gates have been replaced with 3-input AND gates, and the third input of each gate receives feedback from the Q and not-Q outputs. What this does for us is permit the J input to have effect only when the circuit is reset, and permit the K input to have effect only when the circuit is set. In other words, the two inputs are interlocked, to use a relay logic term, so that they cannot both be activated simultaneously. If the circuit is "set," the J input is inhibited by the 0 status of not-Q through the lower AND gate; if the circuit is "reset," the K input is inhibited by the 0 status of Q through the upper AND gate.

When both J and K inputs are 1, however, something unique happens. Because of the selective inhibiting action of those 3-input AND gates, a "set" state inhibits input J so that the flip-flop acts as if J=0 while K=1 when in fact both are 1. On the next clock pulse, the outputs will switch ("toggle") from set (Q=1 and not-Q=0) to reset (Q=0 and not-Q=1). Conversely, a "reset" state inhibits input K so that the flip-flop acts as if J=1 and K=0 when in fact both are 1. The next clock pulse toggles the circuit again from reset to set.

See if you can follow this logical sequence with the ladder logic equivalent of the J-K flip-flop:


The end result is that the S-R flip-flop's "invalid" state is eliminated (along with the race condition it engendered) and we get a useful feature as a bonus: the ability to toggle between the two (bistable) output states with every transition of the clock input signal.

There is no such thing as a J-K latch, only J-K flip-flops. Without the edge-triggering of the clock input, the circuit would continuously toggle between its two output states when both J and K were held high (1), making it an astable device instead of a bistable device in that circumstance. If we want to preserve bistable operation for all combinations of input states, we must use edge-triggering so that it toggles only when we tell it to, one step (clock pulse) at a time.

The block symbol for a J-K flip-flop is a whole lot less frightening than its internal circuitry, and just like the S-R and D flip-flops, J-K flip-flops come in two clock varieties (negative and positive edge-triggered):


REVIEW:
A J-K flip-flop is nothing more than an S-R flip-flop with an added layer of feedback. This feedback selectively enables one of the two set/reset inputs so that they cannot both carry an active signal to the multivibrator circuit, thus eliminating the invalid condition.
When both J and K inputs are activated, and the clock input is pulsed, the outputs (Q and not-Q) will swap states. That is, the circuit will toggle from a set state to a reset state, or vice versa.

DRAWING SUBJECT FOR THE COMPUTER ENGINEERING STUDENTS, FUNCTIONAL OR NOT?

NicoPoIto(NICODENICOLAS)

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Aug 26, 2014 at 10:46pmQuotePost Options

Post by Guest on Aug 26, 2014 at 10:46pm

drawing subject? year, we need that because we are a engineering student. but syempre, there is always be a logic on it. We need the basic skill and fundamentals of drawing subject pero. on higher drawing subject, lumalayo na ito sa ating mga subject. Somewhat na medyo nagpapahirap sa aming mga coet students dahil nga yung iba ay hindi ganun ka creative ang mind pagdating sa pag-iisip ng mga ido drawing. o kaya yung iba ay nanginginig na yung kamay dahil sa trabaho o kung ano pa ang mga ginagawa.. maganda parin manatili ang draw subject but the higher draw subjects must be eliminated.. at palitan ito ng cad .. para kahit papano may matutunan kami na mas makakatulong sa amin

[peace po :)

khangkhungkarnity(welrin)

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Aug 27, 2014 at 8:39amQuotePost Options

Post by Guest on Aug 27, 2014 at 8:39am

...d nmn masama yung drawing subject..pero kung yung pinapagawa na sa inyo...malayong malayo na sa kurso nyo!!...cguro sobra nmn un gnun...ok lng basta may kinalaman sa course..(╯﹏╰）

Cura

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Aug 27, 2014 at 5:15pmQuotePost Options

Post by Guest on Aug 27, 2014 at 5:15pm

Functional

magandang past time para gumawa ng assignment para sa ibang mga subject dahil minsan madadali ang plate at maaga ang uwian, pwede pang magsoundtrip habang nagawa, tsaka engineering students kami kaya kailangan matutunan at kailangan din ng experience para lumevel up at maraming chix sa archi. para din lumawak ang aming IMAGINATION kasing lawak ng a3.tsaka advantage din ito sa mga classmate naming malupit sa drawing kasi kitang kabuhayan na sila nag eenjoy pa sila sa ginagawa nila (Php 50 per plate).

MervinNalangPo:-)

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Aug 27, 2014 at 11:08pm via mobileQuotePost Options

Post by Guest on Aug 27, 2014 at 11:08pm

Ayos lang naman po ang may drawing subject. Basta po may connection po sa course po natin. At saka po hindi po mahirap ang drawing basta gusto mo po ang ginagawa mo. Madali lang naman pong gustuhin ang isang bagay.

At saka po para sa akin mas okay po na may drawing subject for us to learn a new skill o kung marunong ka na pong magdrawing maiimprove nalang po ito.

Yun lang po :-D

Allen Aribal Allada

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Aug 28, 2014 at 5:13am via mobileQuotePost Options

Post by Guest on Aug 28, 2014 at 5:13am

Functional po. Kasi skill din naman ung hinahasa dun which is pwedeng magamit in the future. Pero sana wag naman ung sobra na para sa mga CoET students. Kaya nga po ito ung course na pinili namin kasi dito kami may nalalaman at saka sa tingin namin ay kaya namin. May mga software naman na tulad ng Auto Cad na para sa akin ay mas bagay samin. Doon maaaring matutunan namin ung mga bagay na pwedeng matutunan sa DRAW subject at ang mas maganda pa doon ay sa computer ito na para talaga sa aming mga studyante ng Computer related courses. Pwedeng pwede sa mga di pinalad na magkaroom ng talento sa pagddraw. Un lang :-) 

Un po ung sa side ko.

Have a great day po.

PresidentPoAkoxD(Nico)

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Aug 28, 2014 at 11:55amQuotePost Options

Post by Guest on Aug 28, 2014 at 11:55am

Maganda na meron tayong draw subject pero sana hanggang draw 2 lang.. tapos ituloy natin sa autocad. na mas connected sa subjects/course natin at mas maeenjoy ng isang coet student.. syempre gagamit ng computer, tapos aircon pa yung room xD kidding aside, mas magugustuhan ng isang estudyante ang drawing using cad kasi di tayo magstos, tapos straight yung mga linnya, hindi na baku-bako.. at mas ma eenhance yung skills natin bilang coet student.. back to the topic, functional yung draw subjects, pero sana wag naman yung mga higher draw subject na malaki ang gastos.. e sa cad, computer at flashdisk, oks ka na dba :)

PS

coet 2e maglagay kayo nng name ha :)

Yui~ (Jen Rivera)

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Aug 28, 2014 at 3:49pmQuotePost Options

Post by Guest on Aug 28, 2014 at 3:49pm

Functional po. Kasi bilang isang engineering student expected na talaga un na nakuha mo na ang basics ng technical drawing pero mas maganda sana kung pagkatapos ng basics eh ang susunod dun eh autocad kasi mas may connection yun sa course namin.

Lourenz Bermudez

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Aug 28, 2014 at 7:19pmQuotePost Options

Post by Guest on Aug 28, 2014 at 7:19pm

Functional, kasi po nakakatulong ito na mas malaman natin yung tinutukoy nating larawan o gusto pa nating sabihin :) at mahirap nga mag-imagine ng picture WITHOUT " SCHEMATIC DIAGRAM" .

roel christian C badillo

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Aug 28, 2014 at 7:29pmQuotePost Options

Post by Guest on Aug 28, 2014 at 7:29pm

functioNAL nman,mas madaling maintindihan ang tininuturo kapag may drawing na pinapakita sa isang subject,halimbaWA imagine mo ung symbol NG resistor pag walang drawing.......PEACE COET

AJ MANUEL

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Aug 28, 2014 at 7:36pmQuotePost Options

Post by Guest on Aug 28, 2014 at 7:36pm

functional kasi dagdag naman ito sa skills bilang isang istudyante tayo ng coet tsaka nagagamit naman natin ito sa main subject naten na electronics halimbawa na ginagamit nating drwing sa el ung schematic diagram kailangan natin ito drawing para maintindihan :D ahahahahaha XD (y) tama ba ??? ahahahha

robert wilson

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Aug 28, 2014 at 7:42pmQuotePost Options

Post by Guest on Aug 28, 2014 at 7:42pm

functional kc gumagamit din naman talaga tayo ng drawing sa electronics halimbawa gumagamit tayo ng schematic diagram sa el para maintindihan natin kung pano natin makukuha ung resistance volts current power pano mo makukuha ung sagot kung wlang drawing na nakalagay pano mo malalaman kung paralel or series ung sa schematic diagram :D ahahahahahahhaha

REYes

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Aug 29, 2014 at 4:01pmQuotePost Options

Post by Guest on Aug 29, 2014 at 4:01pm

super functional po sya, kase mas nasusukat po dito ang critical thingking skills namen. mas lumalalim po mag-isip kapag natututo tayong gumawa ng mga drawings kahit basic lang siya.

nightshroud

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Aug 29, 2014 at 4:09pmQuotePost Options

Post by Guest on Aug 29, 2014 at 4:09pm

Yep. It is important, even just the basics. Hindi naman reason na sa computer lang tayo naka focus para sabihing hindi kailangan ng drawing subject. Iba pa din pag kaya mo gumawa ng walang tulong ng computer.

realynnnnAleg

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Aug 29, 2014 at 4:32pmQuotePost Options

Post by Guest on Aug 29, 2014 at 4:32pm

in some terms po oo. hehehe. kaya lang po minsan naiisip namen kung bakit kame nagdodrawing eh computer naman po ung hahawakan namen. pero hidi pala un tama kase po. maraming natatagong dapat alamin kapag nagdrawing kana. hindi lng basta drawing kundi mag iisip ka po talga.