driving relays with little power (4017IC)...tips?

Discussion in 'The Projects Forum' started by JoeBro391, Jul 15, 2010.

  1. JoeBro391

    Thread Starter Member

    May 15, 2010
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    0
    Hey guys, I'm working on a simple circuit. Here's the gist of it: I want to hook up a 4017 IC (used in chaser-circuits) and upon each output going HIGH, I want to activate a relay and pass 12V from a low-grade car-battery through it. The circuit itself is easy; I've made chasers using the 4017 IC before and am well-versed in relays. My problem is that I'm pretty sure the 4017 doesn't have the power to switch an relays. (perhaps a solid-state relay would work?). But I was wondering if anyone had any tip for this. Perhaps some type of driver or bi-lateral switch that would control a very large output from a very small input. From looking at the datasheet, the 4017 outputs a voltage near the supply voltage, but only about 4mA of current. So that's the situation. Any tips would be appreciated. Thanks. -Joe
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Just a plain transistor design between the 4017 and a relay is all you need.
     
  3. creakndale

    Active Member

    Mar 13, 2009
    68
    7
    Transistors and inductive kickback diodes but depending on you relay's coil current draw requirement possibly the ULN2804A.

    creakndale
     
  4. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    Thats about it.

    You could use a relay with a 5v coil, and a transistor or 2 (DARLINGTON PAIR) from the 4017 to the relay coil.
     
  5. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    605
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    Good old DS2003 darlington driver chip. Very easily drives relays.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The DS2003 is a National Semiconductor specific part number for the industry standard ULN2003 7-channel Darlington driver array.
     
  7. JoeBro391

    Thread Starter Member

    May 15, 2010
    68
    0
    thanks guys! -Joe
     
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