Help with dual timer circuit

Discussion in 'The Projects Forum' started by pato5000, Jan 20, 2010.

  1. pato5000

    Thread Starter New Member

    Jan 9, 2010
    2
    0
    Hi there!
    My question would seem a bit novice, but that's what I am...
    I've built a time delay circuit with a dual timer 556. The original schematics uses two 555, but I've changed to a dual 556.
    My problem is that I need to get the same voltage as the input (9v), but I only get around 2.5v.
    How can I manage to get the 9v at the output? I need to keep the board as small as possible, so the less components used would be better.

    Thanks!

    Here's the schematics:
    [​IMG]
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    You likely have a wiring error somewhere, there should be no difference.

    *Spotted it, you don't have pin 4 tied to Vcc. It must be High for the chip to work*

    This will help you with conversions.

    [​IMG]

    For what it's worth, I've recently drawn virtually the identical schematic for someone else on this site. They made it work.

    [​IMG]

    http://forum.allaboutcircuits.com/showthread.php?t=32944
     
  3. pato5000

    Thread Starter New Member

    Jan 9, 2010
    2
    0
    Thanks Bill, I'm going to rebuild the schematics just as yours. By the way, what would be the values for the diode and the transistor? I assume a 1n4001-4007 diode and any NPN transistor, as the 2n2222 would do the job. Am I right?

    EDITED: Bill, thanks again! it works perfectly. I used a 2N2222 transistor and a 1N4007 diode (that's what I had at the reach of my hand).The only thing I had to take out R5 (1K) to give more power to the output. Cheers!
     
    Last edited: Jan 21, 2010
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