Controlling multiple 5V 0.2A fans


I want to control multiple 5V 0.2A fans by PWM (Like here) and want them to share a common power supply. I have a little bit of trouble understanding the following:

If I have, for example, 3 fans and a 0.6A power supply and there is a scenario where just one fan is on (with PWM full on), isn't this one fan getting the 0.6A of current? Or does the fan just draw 0.2A of current even if 0.6A are available?

Thanks in advance :slight_smile:

no the fan (or more precisely the motor for the fan) will only draw the amps it needs to run from the power supply.

You could have a 20 amps power supply it would not be an issue.

Okay, yeah that makes sense.

Now following that: If the common power source (-) is PWM controlled, is there a problem regarding the influence of the PWM on the other fans?

The 3 fans have to be wired in parallel and you need three separate control circuits.
(using the image from your link, something like this)

if you PWM at the common point for all 3 fans, then yes you would impact the 3 of them.

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