Never use resistors for controlling power, that's just waste. PWM is used for controlling power. The dutycycle sets the average power without having any unnecessary waste heat to git rid of.Firstly to control a MOSFET directly from an Arduino requires a logic-level MOSFET, this is mandatory unlessyou want to level-shift to 12V.MOSFETs are picked by max voltage and on-resistance. The on-resistance determines the dissipationfor a given current load.You can switch 5 heating elements in parallel if you want, that's simpler. Is each one 50W, or the total 50W?What is the resistance of each heating element? (ie have you calculated that 50W correctly)
If i use a 9V battery for the Arduino, do i need one more battery for my heating elements?!Thank you.
5 50W heaters = 250W. That's serious power. Standard 9V batteries are good for 0.5W, and arenot 12V!You should explain what you are trying to do, battery power for heating is usually not a sensible approach.
I'm trying to do a heating glove
Seriously?Having 250W in to one hand is going to be an instant barbecue.
You have the wrong heating pad for this design.
And if we assume that I must use this specific element