LED on-off momentary circuit

Discussion in 'General Electronics Chat' started by sonicjunki, Nov 15, 2008.

  1. sonicjunki

    Thread Starter New Member

    Nov 15, 2008
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    Hello,

    I would like to make a circuit to connect to a momentary switch when pressed A LED stays on when pressed again the LED goes off. I would like to power the 2 LEDs with a 9 volt battery. I have 2 switches in a metal chassis with 2 LEDs, the 2 switches are momentary switches. Sorry for my ignorance but i have no idea where to begin, I do have soldiering skill tho. The only electronics store in my area is the dreaded radio shack.

    Thanks so much in advance. Tom
     
  2. Audioguru

    New Member

    Dec 20, 2007
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    The easiest circuit uses an inexpensive Cmos Logic inverters IC, the CD4069.
    It has 6 inverters inside so it can make 3 circuits.

    2 LEDs can be in series then the 270 ohm current-limiting resistor can be 200 ohms.

    Connect the inputs of the unused inverters to ground.
     
  3. sonicjunki

    Thread Starter New Member

    Nov 15, 2008
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  4. Audioguru

    New Member

    Dec 20, 2007
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    Click on the thumbnail pic and you will get a nice big pic. Or right-click on the thumbnail pic and open it or save it as a nice big pic.

    You posted your e-mail address in a forum where millions of SPAM robots will spread your address to millions of other SPAM robots. Then you will get lots and lots of SPAM. Too bad.
     
  5. Wendy

    Moderator

    Mar 24, 2008
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  6. Audioguru

    New Member

    Dec 20, 2007
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    Hi Bill,
    How did you doo dat?
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    Click on the thumbnail, which brings up a new screen with the pictures address on top.

    Highlight and copy this address.

    Sandwich the address between {img}{/img} markers. "[]" = "{}"

    You can even do it on the same page, like so.

    [​IMG]

    I thought it was pretty neat when I discovered it, so I published it here.
     
    Last edited: Nov 15, 2008
  8. SgtWookie

    Expert

    Jul 17, 2007
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    Unfortunately, Radio Shack no longer carries CMOS or TTL logic ICs; just a few analog IC's, transistors, MOSFETs and voltage regulators.

    Probably the least expensive place to get small quantities of digital ICs is DigiKey; they will ship (very) small orders via 1st Class mail.

    You could also build inverters out of discrete components (transistors, resistors) if you wished to do so.
     
  9. Wendy

    Moderator

    Mar 24, 2008
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    Didn't we see one using discrete components about a month ago? Come to think of it, AudioGuru published another one about the same time frame. A lot more complex though.
     
  10. Audioguru

    New Member

    Dec 20, 2007
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    The discrete alternate action circuit is here:
     
  11. Audioguru

    New Member

    Dec 20, 2007
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    Making the schematic bigger.
    [​IMG]
     
  12. defaced

    New Member

    Dec 21, 2006
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    Is there any reason this circuit won't work with a 70LS04? I found the same circuit a couple of places and all specify the CD4069, which I don't have on hand, but I do have a 74LS04 but the circuit is not working on the breadboard.
     
  13. SgtWookie

    Expert

    Jul 17, 2007
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    You know that the 74LS04 requires a 5V supply, and has a much higher current draw than the CD4069 right?

    Other than that, if you're powering a red LED that has a Vf of 2v @20mA, replace the 270 Ohm resistor with a 150 Ohm resistor, and it should work.
     
  14. BillB3857

    Senior Member

    Feb 28, 2009
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    What about using a J-K FF with J & K tied hi? Push button supplying clock input.
     
  15. defaced

    New Member

    Dec 21, 2006
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    Thank you Sgt Wookie. I built the circuit on strip board tonight and was able to get it to work with the 74LS04.
     
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