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Thread: ULN2803A Darlington Array and maybe a TIP120 to switch/control PC case fans

  1. #1

    ULN2803A Darlington Array and maybe a TIP120 to switch/control PC case fans

    Hi

    I'm thinking to control 4 or more PWM PC Case fans from a teensy LC (or 3.2).

    I would do 2 things :

    a) use 5V to send a pwm signal to every fan seperate
    b) switch 12V on and off (group or one at a time)


    a) It's my understanding (after searching the "net" for quite some time) that the ULN2803A Darlington Array (powered by 5V) will be ok to control the PWM signal.


    b) the probable case fans are rated with a 0,12 or 0.3 A "safety current" (I suppose start up current.?), about 5 times the normal current . Would a second ULN2803A (powered by 12V) with 0.5A peak rating be able to start them?


    or I'm I completely wrong? I'm a software guy with (very) limited hardware skills.


    thanks for any insights,

    Alain

  2. #2
    Senior Member+ Frank B's Avatar
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    I'm not that good with hardware/electronics, too, but I've used the unl2803 many (>10??) years ago for a small motor, so yes, I think it can handle a fan.

    On the other hand, It would be easier to use a motordriver. You can buy them as a read-to-use module for arduinos.

  3. #3
    Quote Originally Posted by Frank B View Post
    I'm not that good with hardware/electronics, too, but I've used the unl2803 many (>10??) years ago for a small motor, so yes, I think it can handle a fan.

    On the other hand, It would be easier to use a motordriver. You can buy them as a read-to-use module for arduinos.
    From what I read a uln2803A seems as easy as it gets?

    On the other hand, most modules that I found need 5V.

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