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Author Topic: 3 wire fan controller  (Read 1780 times)

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zc0rp

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3 wire fan controller
« on: February 04, 2015, 15:33:00 PM »
Hi all, I've got a problem with the 3 wire circuit... everything works but...
the max voltage on load is about 7v instead of 12v. i'm using a 12v 5a powersupply.
it's for operating 4 fans on one controller, the fans are max 0.5 amps.
can anyone help me out please? thanks in advance.

i've used this tut:
http://pcbheaven.com/circuitpages/High_Frequency_PWM_Fan_Controller/

kam

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Re: 3 wire fan controller
« Reply #1 on: February 06, 2015, 22:16:55 PM »
Hello zc0rp. Typical mistake on this circuit are the PWM diodes. You do not get all 100% duty cycle.

zc0rp

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Re: 3 wire fan controller
« Reply #2 on: February 09, 2015, 13:52:20 PM »
can you tell me how to fix this? i'm a complete n00b... just that you know ;)

kam

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Re: 3 wire fan controller
« Reply #3 on: February 10, 2015, 21:23:20 PM »
well, actually I can only tell you that you have most likely make a mistake by copying the schematic on the breadboard. I can't tell what you have done wrong. But most common mistake is that you have connect the diodes wrong.