10 second timer

Discussion in 'The Projects Forum' started by markosillypig, Dec 1, 2008.

  1. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
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    hi all again i have got this circuit and i want to use it but i have a little problem
    i would like it to work for about 5 seconds to 15 seconds can anyone help with the modification required
    many thanks
    all
     
    Last edited: Dec 1, 2008
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    What circuit?

    Post a schematic or link....please.

    Ken
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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    Why use a 4060 unless you want multiple outputs?

    You could use a 555 timer if you only need a single delay.
     
  4. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
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    i thought this circuit just fitted the bill
    and i dont have a circuit for the ne555 timer that fits the bill
    it has to drive a 20amp relay for a duration of 5 to 10 seconds
     
  5. hgmjr

    Moderator

    Jan 28, 2005
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    It may be that all you need to do is scale the oscillator by a factor 100 to 1. You should be able to do that by using a 0.1uFd capacitor for C3.

    hgmjr
     
  6. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
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    does anyone have a circuit that would be ok for me to use
    is stead of the 4060 circuit ?
     
  7. iONic

    AAC Fanatic!

    Nov 16, 2007
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    How is the timer to be triggered, manually when needed, when a input signal from another devices goes logic High/Low?...

    Using a 555 R1=100K Pot, C1=200uF will give you from 0 - 22 seconds, aprox.
    The output would be high for this time period.
     
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    Last edited: Dec 3, 2008
  8. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
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    it wants to be opporeted by a remote push to make switch momentary
    then the relay wants to be triggered for aprox 10 seconds or more
     
  9. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
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    what is the Q1 ??
    a 2n222 or a 2n7000 ??
     
  10. iONic

    AAC Fanatic!

    Nov 16, 2007
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    A general purpose NPN, 2N2222, 2N3904...

    You will have to choose a relay that meets your 20A contact rating and one that can be triggered at your 555 supply voltage.
    The absolute max voltage for the LM555 is +18V.
     
    Last edited: Dec 3, 2008
  11. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
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    is the 200uf a ceramic or electrolytic as i can not find any ceramic on ebay ?
     
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  12. Audioguru

    New Member

    Dec 20, 2007
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    I have never seen a ceramic capacitor with a value higher than 1uF. Use an electrolytic capacitor for 200uF or 220uF.
     
  13. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
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    well looking at the scamat the 200uf looks none polorised
    if any one can shed a little light on this please do so
     
  14. mik3

    Senior Member

    Feb 4, 2008
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    In the schematic it is not polarized but because you will use an electrolytic one you have to take care of the polarity. Also, you need to put a resistor between the base of the transistor and the output of the 555. Its value depends upon the supply voltage (it should equal the relays coil voltage but be less than 15 volts), the current the relay needs and the gain of the transistor.
     
  15. iONic

    AAC Fanatic!

    Nov 16, 2007
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    See updated Schematic
     
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