Using Arduino for 3d heating bed

3darduinocontrolmosfet

I would like to use an arduino system to control a heating pad that I will be using in my system.

http://www.amazon.com/Signswise-200x200mm-Silicone-Heating-Printer/dp/B00ZP3XCS4/ref=sr_1_fkmr1_1?ie=UTF8&qid=1447442029&sr=8-1-fkmr1&keywords=400+200+silicone+heater+24v

Although it says 24 v in the link when I click it says 12 v so I don't know whether the heater I got 12 v or 24v. Perfect 🙂
Now the question is…
How do I turn this thing on and off so that it stays at 37C in my system. I have seen various mosfets but I couldn't find any that support 150W. I also don't know how to set up the mosfet system but I can look up the diagrams online so that's not a big issue…
I have seen some logic level mosfets but people raised concerns about some "charging" and "protecting the pin" and all that… so idk. I am a biochemistry student trying to build a nice arduino system and not completely clueless but fairly inexperienced with these systems. so if anyone can explain how can I use mosfets/relays (i think relays only work with ac not like my heater (dc)), I would be really happy.
Thanks a lot.
Have a great day.

Best Answer

The MOSFET doesn't have to dissipate 150 watts. The heating pad does that. The mosfet only needs to flow the 12.5 amps when heater is on, and then block the 12 volts when you want the heater off.
The Rds (resistance) of the mosfet could typically be 31 mohm (0.031 ohms) when on. The power that the mosfet would have to dissipate then would be about 4.8 watts. http://www.mouser.com/ds/2/200/irfz44npbf-222819.pdf

Choose a mosfet with blocking voltage higher than 12 volts. The above mentioned link is for a 55 volt mosfet.

Regarding protecting your arduino (or other system), there are lots of driver circuits you can find here on EE stack exchange that discuss the matter.

As regards relays, there are many many relays that can be used in DC circuits.

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