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
    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


    Mar 14, 2008
    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
    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


    Mar 31, 2012
    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:


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

    Thread Starter New Member

    Aug 9, 2013
    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.
    • jk2.jpg
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  6. MrChips


    Oct 2, 2009
    It is not worth a shot!

    It will not work without switch debounce.

    The switch must be debounced.
  7. WBahn


    Mar 31, 2012
    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.