Variable 12v temperature fan controller

Thread Starter

jmh474

Joined Jun 26, 2014
35
OK so I'm going to be running a Phillips FR984 amplifier for a home theater system, the amplifier only has heat sinks for cooling and I would like to add one or maybe two fans to help with cooling.

I would like it so the fan speed matches the temperature of the amplifier.
Eg hotter the amp the faster the fans will run.

I plan on running the cooling system on its own separate from the amp using the incoming 230v then stepping down to 12v.

So my question is, is there any other projects about with similar properties to mine or could anyone provide me with a circuit diagram that will help me out please, only want something simple thanks
 

wayneh

Joined Sep 9, 2010
16,390
I know you want simple but you really should consider a PWM controller. It’ll be much more robust on the low end of fan speeds, giving smoother gradations of speed. Purely voltage control can crap out on the low end in unpredictable ways. You can buy PWM controllers on eBay ready built and very cheap.
 

AlbertHall

Joined Jun 4, 2014
9,824
I know you want simple but you really should consider a PWM controller. It’ll be much more robust on the low end of fan speeds, giving smoother gradations of speed. Purely voltage control can crap out on the low end in unpredictable ways. You can buy PWM controllers on eBay ready built and very cheap.
Yes, the low speed end is a problem.
One solution for this with the simple version is to add a resistor across the drain and source of the FET. This resistor always some power to the fan and its value is chosen so that it just keeps the fan running.
 

Thread Starter

jmh474

Joined Jun 26, 2014
35
I know you want simple but you really should consider a PWM controller. It’ll be much more robust on the low end of fan speeds, giving smoother gradations of speed. Purely voltage control can crap out on the low end in unpredictable ways. You can buy PWM controllers on eBay ready built and very cheap.
I did look on eBay but I could only find on-off style of cool but as I said I would like it to be in sync with heat generated, in hoping that low speed will be used most of the time as fans can get loud at high speeds.
Any links would be much appreciated
 
Top