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filter AC component by a FAN from a DC circuit with a 1N4007 Diode

spikey1973

Jul 16, 2014
32
Joined
Jul 16, 2014
Messages
32
Hello,

hopefully a question with a simple answer., and sorry i have to use words only.

i have a PSU which supplies a 100kHz switched DC current, 2x 16V with 10A .

1) goes to a microPSU for a PC mainboard.
2) goes to a 20cm PC fan (yeah a large one) which speed is regulated by an arduino board.

now the issue that rose up is that when the fan idles it will function as a AC power generator.. and i really don't want this component to be influencing the DC on the PC mainboard circuit.

so my idea was to place a diode (1N4007) in the circuit so the DC can power the fan, but the AC from the fan can't reach the DC.

some one said that using just one diode in the plus lead would be just fine, but i prefer a second one in the - lead, ofcourse with reversed polarity compared to the + lead diode.

would there be a disadvantage in doing so? and if yes, in what way?

thanks for your help in advance.

Kind regards

Matthieu
 

Minder

Apr 24, 2015
3,478
Joined
Apr 24, 2015
Messages
3,478
Depends on the fan technology, most now are DC in to a BLDC controller so they do not generate to the supply due to the internal circuit isolation.
Not really sure of your actual configuration?
M.
 

spikey1973

Jul 16, 2014
32
Joined
Jul 16, 2014
Messages
32
thank you for your quick respons!

i'm not sure myself if this would be the case, nor how to find that out.
It's been a long time since i bought this fan and i don't know the brand nor type from head and currently it's build in so i would take me a few days to get to it.

if it helps it is a "silent" fan and also there are leds in the casing.. not sure if it has anything to do with it but just thought to mention it.

but taking it is what you said. If i understand correctly and it is not necessairy due to the internal circuit isolation.
but as i'm not sure about this and since it would involve a lot of work to just find out.
I wunder if i could do it anyways.. just making sure.
this as long as there will be no negative side effects" from doing so.
I which case , should i place them like the setup in "B" or should i go for "A" or "C" or even a "D" version?

kind regards.

Matt

ps: i hope the drawing is a bit understandable.

IMG_20171121_211733.jpg
 
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