I'm looking for a MOSFET to use as a switch to trigger a 10w - 12v LED.

1- I have acquired the module with the IRF520 but it seems that, even the seller tells that it is compatible with Pi, it is NOT as its max Threshold voltage is 4, so it would not fully turn on as the Pi gives only 3.3V. A lot of sellers tell it is compatible with Pi but when you look deeper, it is not. That is crazy !

2- Also, I already have another MOSFET: I don't know if I can use the FQP47P06 P MOSFET for this, as in the datasheet it talks about negative threshold voltages I cannot understand. If it is ok to use with my scenario, can you please give me indications about how to use it ?

3- Also I'm searching over the internet the FDN 337N, that would seem that it's the correct one, but I cannot find a place to order it from Spain without having to pay around 20 € for a single MOSFET (shipment costs) or having to wait months for it

Thanks in advance,


  • \$\begingroup\$ Some MOSFET modules have an optical isolator at the input that allows lower voltage MPU outputs to (indirectly) drive the MOSFET. \$\endgroup\$ – StarCat Oct 27 '20 at 8:11
  • \$\begingroup\$ Do you just want to turn the LED on and off, or apply PWM for brightness control? If using PWM, what frequency? \$\endgroup\$ – Bruce Abbott Oct 27 '20 at 8:16
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    \$\begingroup\$ Sorry, but this site considers product suggestions as offtopic. You can try out filters or other kind of parametric search on your local parts dealers site. Or just google for some sort of logic level MOSFET. Besides checking just gate threshold voltage checkout graphs in the datasheet. Vgs(th) is only the minimum level where MOSFET will conduct. It can still still have too high Rds for your current. \$\endgroup\$ – NStorm Oct 27 '20 at 9:02
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    \$\begingroup\$ See also: electronics.stackexchange.com/questions/275524/… \$\endgroup\$ – occipita Oct 27 '20 at 9:07
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    \$\begingroup\$ You actually need something with a threshold Vgs well below the available drive voltage, as you need to pass more than the microamps which the threshold voltage enables. Part "shopping" questions are off topic here, but if you play with the search feature you'll see plenty of past questions where specific part numbers have been implicitly suggested. If you are going to confine yourself to the subset of parts available in through hole packages you could also look at the current offerings by hobby vendors which employ actual engineers to curate their offerings, eg Adafruit. \$\endgroup\$ – Chris Stratton Oct 27 '20 at 14:24

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