[SOLVED] Help in choosing the right MOSFET

[Roman.123]

Hello,

I need help in choosing the right MOSFET for my circuit.
I want to connect a power resistor 50W 4ohm to 12V (from cpu power supply) with a MOSFET.
The Gate pin of the MOSFET will connect to a pwm pin of ATmega328 (pwm 490hz and 5V logic '1').

In conclusion i need to know what MOSFET (and maybe another parts) i should connect from the pwm pin to the resistor and the 12V form power supply.

Thank you for any help.

 

[jiripolivka]

I would use an IRF540 MOSFET to switch the current from a 12 V source to your 4 Ohm resistor. Only please connect the N-channel between ground line and resistor; the other end of the resistor will be connected to +12V.
IRF 540 can be driven by a TTL signal to gate; you can find more MOSFET types among "TTL-controlled MOSFETs". Be sure you use a good heat sink, 4 Ohms at 12 V will dissipate 36W, cool the IRF, too.

 

[Roman.123]

I would use an IRF540 MOSFET to switch the current from a 12 V source to your 4 Ohm resistor. Only please connect the N-channel between ground line and resistor; the other end of the resistor will be connected to +12V.
IRF 540 can be driven by a TTL signal to gate; you can find more MOSFET types among "TTL-controlled MOSFETs". Be sure you use a good heat sink, 4 Ohms at 12 V will dissipate 36W, cool the IRF, too.

Thanks for your help.

Can i use 2N2222 as a driver ? is it fast enough to handle the PWM frequency ?

And the resistor will operate as a heating element in an incubator.

 

[jiripolivka]

Thanks for your help.

Can i use 2N2222 as a driver ? is it fast enough to handle the PWM frequency ?

And the resistor will operate as a heating element in an incubator.

Yes, a 2N2222 can be used at over 200 MHz. I drive a IRF540 directly from a 7400 logic output without problems.

 

[Roman.123]

Ok, thanks alot for the help !!!!!!!