[kohn.ma]

does anyone know where to by 50 or 100 ohm pots? rated around 5w or so? anyway this is a diy fanbus. driving currently two 92mm high cfm fans. the 25 ohm pots in use only will undervolt to around 8v dc. =D

 

[dsavitsk]

Quote:

Originally Posted by kohn.ma /img/forum/go_quote.gif does anyone know where to by 50 or 100 ohm pots? rated around 5w or so?

Digi-Key - CT2153-ND (CTS Corporation Resistor/Electrocomponents - 026TB32R500B1A1)

 

[blackinches]

I built one maybe 8 years ago and I believe I found the rheostats at RadioShack :S

They ran fairly hot and I wouldn't recommend it. There are better fan controlling solutions (Digital Doctor?). Or better yet, use a case with 120mm fans for greater airflow and minimal noise.

 

[kohn.ma]

Quote:

Originally Posted by blackinches /img/forum/go_quote.gif I built one maybe 8 years ago and I believe I found the rheostats at RadioShack :S They ran fairly hot and I wouldn't recommend it. There are better fan controlling solutions (Digital Doctor?). Or better yet, use a case with 120mm fans for greater airflow and minimal noise.

do most of your posts begin with “I.” Take a look at your post history. Me me me. lol

 

[nikongod]

adjustable voltage regulator?

my case fans came with a simple regulator controlled by a low-power pot.

 

[error401]

Yea, I would probably go with a slightly more complicated circuit to avoid having to dissipate so much heat in the pot. If you've got some parts laying around in your junk box, you can probably put together an LM317-based unit for basically nothing. Something like this maybe: GideonTech.com Case Modification - Variable Speed Fan Controller

You might also find something like this 3-component temperature control useful: The Heatsink Guide - All about PC cooling

 

[Gross]

Back in the day on the [H], there was quite a few designs, the most popular was a PWM style fan control.

 

[hardnrg]

PWM can result in a growling sound (my Panaflo fans tend to do it), so you're left with LM317 style linear voltage regulation... or if you want to keep it simple and high power, go for a DioBus with something like a 12-way rotary switch:

Switched Diodes - The Diobus ©