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Suppose i have a scheme that includes integrated circuit with enable input and i want to use mechanical switch in order to activate enable input. For example:

enter image description here

So i've heard that, whenever we are using mechanical button to enable some circuit, we need to avoid direct connection to integrated circuit, instead it is recommended that we use something like this (D flip flop, AND gate and NOT gate) in this configuration because, by directly connecting mechanical button to a IC we can cause a circuit to behave unexpectedly due to mechanics of a button. It could cause a low state to be detected like a high state due to noise or something. Now, has anyone here encountered that kind of problem, is it really necessary to add all of these elements to prevent errors, how this configuration decreases the probability of wrong detection? Any help appreciated!

EDIT: This question is not about if i should debounce this circuit or not, since i know i should, question is, is this scheme representing good debouncing circuit and how?

cdummie
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  • It is called switch bounce / switch bouncing. Lot's of info about it on the internet and how to address it. You can take the number of hits in google as measure if it is needed or not :-). On this site, there are numerous hits on debouncing as well. – Huisman Jun 24 '19 at 17:07
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    Possible duplicate of [Should I consider debouncing my push button?](https://electronics.stackexchange.com/questions/274708/should-i-consider-debouncing-my-push-button) – Huisman Jun 24 '19 at 17:16
  • It doesn't appear to me that your flip-flop clock pins are actually connected to a clock source. Your schematic is missing several critical connections, and I don't see how it would work as a proper debouncing circuit. Maybe you should provide a link to the source. – Elliot Alderson Jun 24 '19 at 18:24
  • @ElliotAlderson Thanks for your response, i dont understand what do you mean when you say that my flip flop clock pins are not connected to a clock, i dont know if you noticed, but blue symbol that has written CLOCK next to it represents clock pulse. – cdummie Jun 24 '19 at 19:39
  • Don't assume that everyone uses the same CAD tools that you are using. So what happens when you build the circuit? Does the little blue symbol appear on the board and provide a clock? If you are worried about clocking something, we need to know where the clock is coming from. – Elliot Alderson Jun 24 '19 at 19:49
  • When i run the circuit, every port that is connected to a clock starts blinking, changing colors blue to red and so on, blue represents logic zero, red represents logic 1. – cdummie Jun 24 '19 at 20:04
  • All you need is a cap across switch with an RC delay > max bounce time which may be 1ms for certain buttons to 10ms for bigger momentary buttons – Tony Stewart EE75 Jun 24 '19 at 20:57

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