1. Kaiser Ed Bayawa

    Thread Starter Member

    Mar 19, 2015
    60
    6
    hi everyone I am having problem with my circuit. how can I make output up to 8 volts? see my attachment
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    You'll have to use a higher supply voltage. The timer can only get within 2 diode drops of the supply...

    What problem you're trying to address?
     
    Last edited: Jun 12, 2015
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    The timer shown in the schematic is the CMOS version...
     
  4. Kaiser Ed Bayawa

    Thread Starter Member

    Mar 19, 2015
    60
    6
    i want to use it to my motorcycle for relay of its horn but it needs 8 v to work
     
  5. Kaiser Ed Bayawa

    Thread Starter Member

    Mar 19, 2015
    60
    6
    can you give me a link or a photo please
     
  6. dl324

    Distinguished Member

    Mar 30, 2015
    3,242
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    Which timer are you using? NE555 or a CMOS variant?

    Show the schematic of you're circuit!

    The motorcycle's battery voltage is 8V??
     
  7. dl324

    Distinguished Member

    Mar 30, 2015
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    My bad... I didn't pay any attention to the part number in the schematic because the title said NE555...
     
  8. dl324

    Distinguished Member

    Mar 30, 2015
    3,242
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    High output specs for TI LMC555 timer are unexpectedly poor...
    cmosTimerOut.jpg
    TI datasheet didn't give a schematic.
     
  9. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    You have several problems with this thread. A CMOS 555, which a 7555, simply does not have the drive you want. It simply can not provide enough current.

    The 7555 can go rail to rail, hit both 0V and the power supply voltage.

    I have even used 7555 at low voltages (3V) without a resistor because the drive of this chip is so low.

    Bill's Blog

    Chapter 8 - 555 Timer Circuits

    I am a fan of the 555. I have written a chapter in the AAC textbook showing various circuits this chip can use.
     
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