I am making my own stir plate. I have a nice fan 24volt. I have an adaptor that plugs into the wall that feeds the fan 24volts. I need to slow it down with a rheostat/ potentiometer. Do they make rheostats for 12volts, 24 volts etc...or will any radioshack potentiometer work.
stirplate question
- Thread starter Dark_Ale
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You need to understand circuits to answer that question. A potentiometer of any kind will work in theory, as they just increase resistance on the circuit, but the wrong kind can either not fully shut off the current, or if too strong shut it off so fast that basically it is either on or off. You really need to know exactly what you're putting into the circuit. Don't guess. if you're unsure, you should probably not do it. If you have some software that helps design circuits, then you would be safer.
I don't know if you know anyone that could make a small electronic circuit for you, it is not to complicated and ideal for what you want if you fancy a go yourself.
The device is a voltage controller LM317
http://www.national.com/mpf/LM/LM317.html
Good luck
Cheers
Simon
The device is a voltage controller LM317
http://www.national.com/mpf/LM/LM317.html
Good luck
Cheers
Simon
See the link below it is for a device LM317
Voltage regulator.
http://www.national.com/mpf/LM/LM317.html
It's not to difficult to make just remember a heatsink on the device.
Good luck
Cheers
Voltage regulator.
http://www.national.com/mpf/LM/LM317.html
It's not to difficult to make just remember a heatsink on the device.
Good luck
Cheers
Um, those are for 120v no? Completely wrong kind. Not 12 or 24v.
BBL_Brewer
Well-Known Member
I also recommend the LM317. I went the potentiometer route on my first couple plates and it sucked. Once I went with the LM317's it's been smooth sailing ever since. You can get them on ebay pretty cheap. Good Luck.
HenryVance3
Well-Known Member
That is exactly what I did and it works awesome! I actually went an easy route and bought a 12 volt dc fan regulator for 6 dollars on amazon and wired it in.
tmd49
Active Member
pompeiisneaks said:
This is my problem; the pot is either off or on, no variable resistance. Should I get a bigger/stronger pot? I hae a 6v DC power supply with a 12v fan.
BBL_Brewer
Well-Known Member
Try an LM317 or check out flomasters post below.
Originally Posted by Flomaster
so after reading the other 200 page DIY thread about using an old computer fan, hard drive magnets, radio shack potentiometer and a random power supply I attempted to build my own. after many a failed attempts and finally getting a working combination using a 18V JBL power supply I found it was spinning to fast for my liking even on the slowest setting.
I saw another thread about this usb fan on amazon.com and said WTF might as well try it out. well let me tell you this works fantastic and is super easy to put together.
http://youtu.be/f9Oij-NCWds
Video Link:
here is a link Video Link: http://www.amazon.com/dp/B00080G0BK/?tag=skimlinks_replacement-20 to my fan its an 80mm fan I didn't think I needed to spend the extra coin on the 120mm fan.
-=Jason=-
Last edited by a moderator:
That's the trick, figuring which you need for your specific fan. I don't know the answer. Sorry.
CalmDreamer
Member
check here, it has all the info needed 
http://www.stirstarters.com/
http://www.stirstarters.com/camiller
Well-Known Member
No, if you put 120v into a LM317 your going to fry it. The LM317 voltage regulator will take any input voltage up to about a max of 38v and allow you to use a potentimeter to reduce the output. The output is capped to about 1v under your input voltage so with the right potentimeter your 24v supply could give you a output of 1(?)-23v to the fan. Odds are the stall speed of the fan will be your actual lowest threshold and be somewhere above the lowest threshold of the LM317.
info and a calculator:
http://www.electronics-lab.com/articles/LM317/
