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  1. #1
    DF Moderator BIG-TED's Avatar
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    Default Need help with a flasher circuit

    Been asked by my old boy to make a circuit to flash a dummy methanometer, for a talk he is doing.

    What he wants, 6 leds to flash all together once about every 10 seconds.
    Looking around my bits I have
    15 5mm red leds,
    Lots of capacitors various values
    Lots of resistors various values
    10 555 timer chips
    Some breadboard
    Some transistors both pnp and npn
    Should be able to rob a 9v battery terminal from something.

    Can any knock me up a circuit using the above parts and I'll make it and keep him off my case

    Thanks
    Ted

    The led values are
    Forward voltage 1.8-2.1v
    Forward current 20 ma
    Reverse voltage 5v
    Reverse current <=10ua
    Last edited by BIG-TED; 1st October 2014 at 06:09 PM.
    Run your wife a nice hot bath, light some candles & pour some wine. Then you've at least 40 mins on the xbox plus a clean wife.

    Experts... x is an unknown quantity and spurt is a fast drip.

  2. #2
    DF VIP Member Pegasus's Avatar
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    Default Re: Need help with a flasher circuit

    Plenty on Google mate

    [Only registered and activated users can see links. ]

    Changing the value of the electrolytic (normally C1) will alter the flash rate, the 555 has a max current output of 200mA so you should be good to go direct with only 6 LED's @ 20mA each
    Understeer is when you hit a wall with the front of your car
    Oversteer is when you hit the wall with the back of your car
    Horsepower is how fast your car hits the wall
    Torque is how far your car sends the wall across the field once you've hit it

    Thanks to Pegasus

    BIG-TED (6th October 2014) 


  3. #3
    DF Super Moderator Over Carl's Avatar
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    Default Re: Need help with a flasher circuit

    I bet you've got a spare indicator relay somewhere, although that wouldn't be educational for the kid.

  4. #4
    DF Jedi plug1's Avatar
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    Default Re: Need help with a flasher circuit

    Or you could use logic gate ics ,but you would need to step up the current to drive the LEDs

  5. #5
    DF VIP Member Pegasus's Avatar
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    Default Re: Need help with a flasher circuit

    Quote Originally Posted by Over carl View Post
    I bet you've got a spare indicator relay somewhere, although that wouldn't be educational for the kid.
    It would have to be fully electronic, but even then I doubt 120mA would be enough of a drain to get it going to be honest.
    Understeer is when you hit a wall with the front of your car
    Oversteer is when you hit the wall with the back of your car
    Horsepower is how fast your car hits the wall
    Torque is how far your car sends the wall across the field once you've hit it

  6. #6
    DF Moderator BIG-TED's Avatar
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    Default Re: Need help with a flasher circuit

    Sorted thanks chaps found a couple of useful sites.
    [Only registered and activated users can see links. ]
    And
    [Only registered and activated users can see links. ]

    Thanks

    Ted
    Run your wife a nice hot bath, light some candles & pour some wine. Then you've at least 40 mins on the xbox plus a clean wife.

    Experts... x is an unknown quantity and spurt is a fast drip.

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