Author Topic: fan thermo switch east simple - temp control  (Read 3670 times)

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Offline user1235423643Topic starter

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fan thermo switch east simple - temp control
« on: August 12, 2016, 04:32:01 pm »
hello, can anyone help find some info on how to make a temp control switch

i want to turn on a cooling fan when temp is at X or over. simple and cheap to build.

some extra factors if possible
* speed control (high the temp faster the speed)
* temp range adjustment (pot)

thanks
 

Offline Seekonk

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Re: fan thermo switch east simple - temp control
« Reply #1 on: August 12, 2016, 05:20:50 pm »
I buy these digital 12V ones on ebay for a little over 4# shipped nice features like relay out, display, delay, diff, heating or cooling and even correct the temp.  Blame Jimmy Carter if you can't read C.
 

Offline Ice-Tea

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Re: fan thermo switch east simple - temp control
« Reply #2 on: August 12, 2016, 05:32:03 pm »
Airpax for on/off. Up to 48V or thereabout.

Offline user1235423643Topic starter

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Re: fan thermo switch east simple - temp control
« Reply #3 on: August 13, 2016, 07:33:18 am »
umm like to shared a link or something?
 

Offline Ice-Tea

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Re: fan thermo switch east simple - temp control
« Reply #4 on: August 13, 2016, 07:41:42 am »
 
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Offline user1235423643Topic starter

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Re: fan thermo switch east simple - temp control
« Reply #5 on: August 13, 2016, 02:19:14 pm »
your link doesn't work. if you dont have a valid reply dont bother please.
 

Offline Ice-Tea

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Re: fan thermo switch east simple - temp control
« Reply #6 on: August 13, 2016, 04:37:51 pm »
Holy crap, dude. Google it. First hit.

Offline ZeTeX

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Offline user1235423643Topic starter

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Re: fan thermo switch east simple - temp control
« Reply #8 on: August 14, 2016, 09:22:58 am »
thanks ZeTeX,   

@ice-tea dont bother with your useless comments.
 

Offline user1235423643Topic starter

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Re: fan thermo switch east simple - temp control
« Reply #9 on: August 14, 2016, 09:25:41 am »
looking for something more simple

like a transistor and a variable output controlled by the base resistor
 

Offline Refrigerator

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Re: fan thermo switch east simple - temp control
« Reply #10 on: August 14, 2016, 10:14:13 am »
I made a thread about a circuit that i came up with, which uses a diode as a temp sensor, even the P-N junction on a transistor can be used.
Here's the schematic:
https://gyazo.com/a938d6d9342c326f5a9762de5edf3482
The full thread:
https://www.eevblog.com/forum/projects/i-came-up-with-this-temp-controlled-fan-circuit/msg691717/#msg691717
I hope it's what you're looking for.
I have a blog at http://brimmingideas.blogspot.com/ . Now less empty than ever before !
An expert of making MOSFETs explode.
 

Offline user1235423643Topic starter

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Re: fan thermo switch east simple - temp control
« Reply #11 on: August 24, 2016, 05:03:06 pm »
more simple.

one transistor and a theoristor on the base to vary the voltage?

 
 

Offline ZeTeX

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Re: fan thermo switch east simple - temp control
« Reply #12 on: August 24, 2016, 06:43:57 pm »
more simple.

one transistor and a theoristor on the base to vary the voltage?
You mean mosfet and get the right voltage to operate it in it linear mode?
I bet just finding and the price of the right mosfet will be more expensive then LM317.
 

Offline user1235423643Topic starter

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Re: fan thermo switch east simple - temp control
« Reply #13 on: August 29, 2016, 05:35:48 pm »
hello, thats might have been an idea but

i have a 20-30v output or a 8-6v input boost conv i can tap the power from

using a thermister and a LM317 would give me a voltage drop overhead and a output that will vary on the input.

if my boost conv. is variable then it will effect the lm317

i want to drive a 12v fan 5-12v in speed. so it wouldnt work well i dont think?
 

Offline ZeTeX

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Re: fan thermo switch east simple - temp control
« Reply #14 on: August 29, 2016, 09:02:41 pm »
hello, thats might have been an idea but

i have a 20-30v output or a 8-6v input boost conv i can tap the power from

using a thermister and a LM317 would give me a voltage drop overhead and a output that will vary on the input.

if my boost conv. is variable then it will effect the lm317

i want to drive a 12v fan 5-12v in speed. so it wouldnt work well i dont think?
You have a fairly simple problem that you are trying to over - complicate,
How do you want to connect the thermistor to the LM317?
and if you have LM317 and a thermistor just use the schematic I showed you before.
 

Offline user1235423643Topic starter

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Re: fan thermo switch east simple - temp control
« Reply #15 on: September 03, 2016, 02:44:19 pm »
will still give me the same problem
 


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