fan thermo switch east simple - temp control - Page 1
Forum section: electronics / beginners

author: user1235423643
author_rank: Regular Contributor
timestamp: August 12, 2016, 04:32:01 pm
content: hello, can anyone help find some info on how to make a temp control switchi 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

author: Seekonk
author_rank: Super Contributor
timestamp: August 12, 2016, 05:20:50 pm
content: 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.

author: Ice-Tea
author_rank: Super Contributor
timestamp: August 12, 2016, 05:32:03 pm
content: Airpax for on/off. Up to 48V or thereabout.

author: user1235423643
author_rank: Regular Contributor
timestamp: August 13, 2016, 07:33:18 am
content: umm like to shared a link or something?

author: Ice-Tea
author_rank: Super Contributor
timestamp: August 13, 2016, 07:41:42 am
content: No problem!http://lmgtfy.com/?q=Airpax

author: user1235423643
author_rank: Regular Contributor
timestamp: August 13, 2016, 02:19:14 pm
content: your link doesn't work. if you dont have a valid reply dont bother please.

author: Ice-Tea
author_rank: Super Contributor
timestamp: August 13, 2016, 04:37:51 pm
content: Holy crap, dude. Google it. First hit.

author: ZeTeX
author_rank: Frequent Contributor
timestamp: August 13, 2016, 08:25:45 pm
content: https://www.eevblog.com/forum/projects/'active'-dc-fan-controller/msg896072/#msg896072

author: user1235423643
author_rank: Regular Contributor
timestamp: August 14, 2016, 09:22:58 am
content: thanks ZeTeX,@ice-tea dont bother with your useless comments.

author: user1235423643
author_rank: Regular Contributor
timestamp: August 14, 2016, 09:25:41 am
content: looking for something more simplelike a transistor and a variable output controlled by the base resistor

author: Refrigerator
author_rank: Super Contributor
timestamp: August 14, 2016, 10:14:13 am
content: 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/a938d6d9342c326f5a9762de5edf3482The full thread:https://www.eevblog.com/forum/projects/i-came-up-with-this-temp-controlled-fan-circuit/msg691717/#msg691717I hope it's what you're looking for.

author: user1235423643
author_rank: Regular Contributor
timestamp: August 24, 2016, 05:03:06 pm
content: more simple.one transistor and a theoristor on the base to vary the voltage?

author: ZeTeX
author_rank: Frequent Contributor
timestamp: August 24, 2016, 06:43:57 pm
content: Quote from: user1235423643 on August 24, 2016, 05:03:06 pmYou 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.

author: user1235423643
author_rank: Regular Contributor
timestamp: August 29, 2016, 05:35:48 pm
content: hello, thats might have been an idea buti have a 20-30v output or a 8-6v input boost conv i can tap the power fromusing 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 lm317i want to drive a 12v fan 5-12v in speed. so it wouldnt work well i dont think?

author: ZeTeX
author_rank: Frequent Contributor
timestamp: August 29, 2016, 09:02:41 pm
content: Quote from: user1235423643 on August 29, 2016, 05:35:48 pmYou 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.

author: user1235423643
author_rank: Regular Contributor
timestamp: September 03, 2016, 02:44:19 pm
content: will still give me the same problem