IRF520 MOSFET Driver Module Help Needed

I’m trying to use an IRF520 MOSFET Driver Module to regulate a dew heater (about 3 watts). It’s nothing fancy, just an adaptation of the PWM sketches and circuits floating around. The problem is the Arduino resets after a few minutes if the digital pin’s level is set to anything lower than 255. The specs on the module indicate that it is suitable for PWM and the wiring only requires the signal (from pin 9 in this case), VCC (+5v), and a ground. Even with no load applied a reset happens, but if I disconnect the signal wire from pin 9 the sketch runs fine. I thought the module was bad at first, but another one behaves in the same way. Ideas?

TIA, Chuck



Where did you get the module, can you post a link to it, usually the supplier sites give schematics of their PCBs.

The IRF520 is not a logic level MOSFET, so it will not turn fully ON with only 5V gate voltage.

What are you using to power the project?

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

Tom.... :slight_smile:


I found the site.

Does the reset occur with the load side INCLUDING the power supply for the load disconnected, and the arduino side connected?

Tom.... :slight_smile:

The reset happens with no load or external power connected to the terminal blocks.

Interesting, can you post a picture of you project as well as a circuit diagram please.

Tom..... :slight_smile:

What voltage is the heater? What decoupling do you have on the heater supply? You seem
to have issues when the PWM is running (255 is the same as digitalWrite (pin, HIGH)), suggesting
EMI from your output or back-coupling via the devices internal capacitance.

You should be using a logic level MOSFET if driven from 5V, or use a MOSFET driver chip powered
at 12V to level shift and do a proper job of gate drive.

The IRF520 has very poor performance, its many many decades old. A modern MOSFET is the
correct choice.