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555 PROBLEM

Discussion in 'Electronic Basics' started by Junkmail789, Dec 21, 2003.

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  1. Junkmail789

    Junkmail789 Guest

    I got my 555 timer circuit working it's .3 sec per cycle. Problem is I'm
    driving a relay that is 5 volts and the timer barely even lights a test LED
    I hook up to it. Do I need to run a separate power line besides the output
    of the timer to a relay?

    I'll do some more research today but if anyone has a place to start it would
    be appreciated.
     
  2. CFoley1064

    CFoley1064 Guest

    I got my 555 timer circuit working it's .3 sec per cycle. Problem is I'm
    This should do the trick. You need protection from the inductive kick of the
    relay, and the 555 drive current may not be enough to drive the relay. If your
    relay coil is less than 100 ohms, you might want to do something else. The two
    resistors coming from pin 3 of the 555 could be 1K to 2.2K.

    View in fixed font (M$ Notepad)

    VCC VCC VCC VCC
    + + + +
    | | | |
    .-. 8| 4| |
    | | .---o---o----. o------.
    | | | | | |
    '-' | | | |
    | | | - |
    | 7 | | ^ |
    o----o | | _|_
    | | | | RY1|_/_|-
    .-. | |3 | |
    | | | 555 o----. o------'
    | | 6 | | | |
    '-'.--o | | |
    | | | | .-. |
    | | | | | | |
    o-o--o | | | '---o
    | 2 | | '-' |
    | | | | |/
    --- | | o-----o Q1
    --- | | | |>
    | '---o--------' .-. |
    | 1| 5| | | |
    | | --- | | ===
    | | --- '-' GND
    | | | |
    | | | |
    | | | |
    === === === ===
    GND GND GND GND



    created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

    Good luck.
    Chris
     
  3. Brian Oakley

    Brian Oakley Guest

    You could always use a transistor on the output of the timer to drive the
    relay.
    Brian
     
  4. Brian Oakley

    Brian Oakley Guest

    How can I see your schematic drawing properly?
    Brian
     
  5. As Chris said:

    If not, and you're instead using a *proportional* font, the ASCII
    won't line up properly.

    And here is a similar schematic in conventional format.
    http://www.terrypin.dial.pipex.com/Images/555Astable+Driver.gif
     
  6. Chaos Master

    Chaos Master Guest

    Brian Oakley said those words of wisdom from the arcane mages in
    sci.electronics.basics:
    Copy and paste it into Notepad.
     
  7. If you are using Outlook Express, click View, Text size, Fixed.

    Cheers!

    Chip Shults
    My robotics, space and CGI web page - http://home.cfl.rr.com/aichip
     
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