JK Flip Flop Design Question

Discussion in 'General Electronics Chat' started by audia4x4, Aug 9, 2013.

  1. audia4x4

    Thread Starter New Member

    Aug 9, 2013
    2
    0
    First off Hello everyone I am new to the forum as you can see so I am sorry if this is in the wrong section.

    Here's the deal, I want to turn a momentary push button into an on/off toggle switch to control a remote turn on for a automotive subwoofer amplifier. I am using an IC chip with a jk flip flop circuit. What I need to know is if the diagram I post below is correct. In the diagram a switch is connected to the clock pulse with +12volts attached to it and jumped to the j and k causing them to constantly be high(1). With j and k high this will leave my output (Q) high(1) until a pulse is clocked switching my output to low. If this is incorrect please let me know what I need to change (pics help the most).

    Diagram high output (on):*http://db.tt/90yidbre*

    Diagram low output (off):*http://db.tt/vr7Yt0di

    P.s. in the diagram I am using a battery as my power supply but in the real application it will be turned on using the output from the back of my headunit ~5v I think
     
  2. crutschow

    Expert

    Mar 14, 2008
    12,977
    3,220
    That should work but you need a debounce circuit if it's being triggered by a mechanical push-button.
     
  3. LDC3

    Active Member

    Apr 27, 2013
    920
    160
    The FF changes on a low to high transition (or is it high to low). Therefore, just closing a switch may not change the FF, but closing and opening the switch will. You should use a momentary switch so every time you push the switch, the FF will change states.
     
  4. WBahn

    Moderator

    Mar 31, 2012
    17,715
    4,788
    In general, an automotive electrical environment is a pretty harsh place. I think this has gotten better in newer cars because of all the electronics they have -- but even so those electronics are specifically designed for use in noisy automotive environments. The 5V supply coming out of your amp may be fairly clean, but I have no idea.

    As mentioned previously, you want to do some serious debouncing on your switch. I would recommend using a SPDT switch and come RC filtering, perhaps something like the following:

    [​IMG]

    You might try 10kΩ resistors and 0.1μF capacitors.
     
  5. audia4x4

    Thread Starter New Member

    Aug 9, 2013
    2
    0
    thank you for the replies everyone! here is better drawn diagram that is hopefully easier to understand. i also fixed some symbol errors i made on my previous sketch. At the moment i think I am going to try using the circuit without a debounce circuit only because i am working in very limited space where the circuit will be installed. I understand this could be a problem depending on the switch and the clarity of the signal but it is worth a shot for now.

    also the positive edge trigger or negative edge trigger should not be an issue with a momentary switch.
     
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  6. MrChips

    Moderator

    Oct 2, 2009
    12,415
    3,354
    It is not worth a shot!

    It will not work without switch debounce.

    The switch must be debounced.
     
  7. WBahn

    Moderator

    Mar 31, 2012
    17,715
    4,788
    We can't stop you. But don't expect a very sympathetic response when you come back complaining about all the hours you spent trying to figure out why sometimes it works and sometimes it doesn't.
     
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