2A and 3v Load on arduino

Hello i have a 3v heater that needs 3A to get hot and i need to supply it to arduino , i have a IRFZ20 and other arduino starter kits equipements.Can you help me on how to do it ? since when i connect the heater to the MOSFET it gets super hot.

I also have 4n35 . i don't know if it can help me .

Please any ideas . Thanks

(mod edit)
heater .png

heater .png


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hello i do not see the answer.

Can you help me please ?

The MOSFET gets hot because it will not fully turn on with 5V on the gate. Note the Rds(on) is specified at 10V. That is not a logic level device.

Obviously, the circuit you have is not the same as the one you posted a diagram of. Please post a schematic of the circuit as it actually exists. I suspect there will be additional problems, besides the one mentioned in reply #3.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Please include power supplies and component labels.

Thanks.. Tom... :slight_smile:

3v heater that needs 3A to get hot

You will need a separate 3V, 3A or greater power supply for the heater.

A logic level N-MOSFET, like this one, can be used to switch the heater on and off. Don't forget to connect the grounds.

It's possible that you could use the 4N35 to switch 12V or more (2 9V batteries in series will do, you need almost zero current) to open the Gate on that FET you have.

It would be a kludge for sure but you could run that kludge until you get a logic level power FET.

Kind of like this:

(It was noted in the original thread that there should be a diode across the motor if that is what it is. :roll_eyes: )

And I would of course always put the 10k resistor to the left of the 470. :grinning:

Compared to using a logic level power FET, an opto to open a FET seems a bit of a fix.

Like using opto-couplers on relay modules?

To isolate the relay, what they're made for even if the user wastes that.