fan

kinser · 13th January 2004, 04:42 PM

Hi
I have a computer fan that I want to use for my amps heatsink
the prombel:
my power supply output is 30 volts DC, how do I get 12 volts DC for the fan from 30 volts?
thanks kinser

Richard C · 13th January 2004, 06:46 PM

A 78 series 1 amp 12V voltage regulator will do the job. Download the data-sheet for specs and application notes.

joensd · 13th January 2004, 07:12 PM

As fans increase the efficiency of the heatsink substantially it would be probably enough to supply 6-9V to the fan.
You´ll get much lower noise as well of course and the fan draws less current.
Watch the power dissipation of the 78xx-regulator.
Probably around 2W or so.

If you don´t have a class a amplifier you could also think about a temperature-control for your fan which only kicks in when it´s needed.

Cheers
Jens

millwood · 13th January 2004, 07:23 PM

I used a lm simple switching regulator (I think it is 2596) for my fans. It runs very cool (>90% efficiency) and needs 5 parts (including the regulator itself). Highly recommended.

You can put multiple fans in series (2 or 3 of them in your case) or to use a power resistor if your fan doesn't draw too much current.

joensd · 13th January 2004, 10:12 PM

the solution with a switcher would be the most elegant of course
but the main supply will also "see" the switching peaks as well!?
never tried and listened if it´s a substantial noise that´s created but an amplifier with poor PSRR probably won´t like it (or better your ears)

lucpes · 26th April 2004, 06:49 PM

Have +/- 63V rails... how can I get 5V for a fan?

lucpes · 27th April 2004, 10:09 AM

Quote:

Originally posted by lucpes
Have +/- 63V rails... how can I get 5V for a fan?

Found the answer: locate an old (mobile phone charger?) 5V gizmo, hack it, and you have your 5VDC source.

13th January 2004, 04:42 PM	#1
kinser diyAudio Member Join Date: Jan 2004 Location: R'aanana	fan Hi I have a computer fan that I want to use for my amps heatsink the prombel: my power supply output is 30 volts DC, how do I get 12 volts DC for the fan from 30 volts? thanks kinser

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13th January 2004, 06:46 PM	#2
Richard C diyAudio Member Join Date: Jul 2003 Location: Nottingham, England	A 78 series 1 amp 12V voltage regulator will do the job. Download the data-sheet for specs and application notes.

13th January 2004, 07:12 PM	#3
joensd diyAudio Member Join Date: Dec 2001 Location: Germany	As fans increase the efficiency of the heatsink substantially it would be probably enough to supply 6-9V to the fan. You´ll get much lower noise as well of course and the fan draws less current. Watch the power dissipation of the 78xx-regulator. Probably around 2W or so. If you don´t have a class a amplifier you could also think about a temperature-control for your fan which only kicks in when it´s needed. Cheers Jens

13th January 2004, 07:23 PM	#4
millwood Account Disabled Join Date: Apr 2003 Location: US	I used a lm simple switching regulator (I think it is 2596) for my fans. It runs very cool (>90% efficiency) and needs 5 parts (including the regulator itself). Highly recommended. You can put multiple fans in series (2 or 3 of them in your case) or to use a power resistor if your fan doesn't draw too much current.

13th January 2004, 10:12 PM	#5
joensd diyAudio Member Join Date: Dec 2001 Location: Germany	the solution with a switcher would be the most elegant of course but the main supply will also "see" the switching peaks as well!? never tried and listened if it´s a substantial noise that´s created but an amplifier with poor PSRR probably won´t like it (or better your ears)

26th April 2004, 06:49 PM	#6
lucpes diyAudio Member Join Date: Dec 2003 Location: Iasi	Have +/- 63V rails... how can I get 5V for a fan?

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