Heat-Activated External Cooling Fan

[Aaron407 10+ year member]

Has anyone used a thermistor/wheatstone bridge/op-amp circuit to act as a temperature-activated control for an external fan to cool an amp? If you have, could you email me some schematics? I'll be using a thermistor with a negative temperature coefficient (reduces resistance with increased temperature). Thanks in advance.

407

Click to read more...

 

[avistar23 10+ year member]

I know what your looking for, and ive seen the schematics many times but i lost all my favorites due to a virus messing up my hardrive and cant remeber the site, ill try find it for you and post it.

-Mike

 

[avistar23 10+ year member]

Well i found this one, it dosent use a thermistor but it looks quite interesting.

http://sound.westhost.com/project42.htm

-Mike

 

[Aaron407 10+ year member]

Thanks anyway, but I actually ended up finding a really simple schematic. If anyone else is interested, let me know and I'll post it.

407

 

[fugit 10+ year member]

Thats a cool idea, I was thinking of getting some fans but never thought of them being heat activated. I was just going to make a normal switch. What do you think a good temp would be to have them kick on?

 

[Aaron407 10+ year member]

Here's the schematic if anyone's interested (I'm in electrical engineering, so this stuff 's gold to me). The 5K potentiometer basically controls the temperature the fan will turn on at, and the thermistor would be mounted directly on the amplifier, probably with heatsink compound. As for the temperature it should turn on at, I'm really not sure. It would probably be best to use a thermometer with an external probe to set it.

407

 

[fugit 10+ year member]

I saw this for computers.

http://www.gruntville.com/reviews/fans/silenx/

I don't know if you want to be lazy, but it looks easy.

 

[Aaron407 10+ year member]

Thanks, but it's good board making practice for me to do it on my own.

407

 

[fugit 10+ year member]

Right on, I'm cluless when it comes to that stuff so I think I'll just be lazy. I'd like to try it though, I'd like my fans only to be on at certain temps so I don't have them running the whole time.

 

[sumone 10+ year member]

There's also one on bcae1.com: