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So i want to make a rgb led strip setup with irfz44n mosfets. The datasheet says that once 4.5v is applied on the gate the mosfet will start to let through about 9 amps. My psu is only 5 amps. Does this mean i can't dim the colors when using the arduino's analog pins?

EDIT: Sorry for not being clear. I want to power my common anode led strip with a 12v 5a psu. Every color (red, green blue obviously) is connected to his own mosfet's drain, source pin going back to the psu's and arduino's ground. The gate i want to power with an arduinos analog pin. My question now is, will i be able to dim the leds since the gate-to-source picture on the datasheet says at 4.5 volts on the gate the mosfet will start to let 9 amps flowing from drain to source.

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closed as unclear what you're asking by Marcus Müller, DoxyLover, Andy aka, Wesley Lee, Voltage Spike Aug 7 '17 at 21:12

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ It means you haven't enough power to light your LEDs. \$\endgroup\$ – Transistor Aug 5 '17 at 16:33
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    \$\begingroup\$ I don't see a link to your LEDs nor a schematic? \$\endgroup\$ – Andy aka Aug 5 '17 at 16:38
  • \$\begingroup\$ try phrasing as '... the mosfet will start to let through up to 9 amps'. \$\endgroup\$ – Neil_UK Aug 5 '17 at 16:43
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    \$\begingroup\$ voting to close as unclear, since without schematic, it's not clear what OP really tries to do. \$\endgroup\$ – Marcus Müller Aug 5 '17 at 16:45
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    \$\begingroup\$ You really don't want to analog dim the LEDs. Your MOSFETs will be dropping a lot of power and will get quite hot. You need to use PWM dimming. \$\endgroup\$ – DoxyLover Aug 5 '17 at 17:49
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IRFZ44N can't be driven from 5V (the datasheet specifies no RdsON for Vgs=5V).

See this answer, which is basically the same problem, and use the same FET.

https://electronics.stackexchange.com/a/322098/13616

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Regarding current.

let through about 9 amps

9 Amp is the maximum current the MOSFET can handle at that VGS without becoming to hot and break down and fail. If your LED consumes 5 Amp then you are below the maximum limit of 9 Amp = OK!

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  • \$\begingroup\$ So i will be able to dim the leds although the minimum volt stated on the gate in the datasheet is 4.5v? \$\endgroup\$ – Anonymus Aug 5 '17 at 18:09
  • \$\begingroup\$ I would use a additional transistor to increase the VGS on the MOSFET. arduinodiy.files.wordpress.com/2012/05/fet2_thumb.gif?w=535 \$\endgroup\$ – MatsK Aug 5 '17 at 18:18
  • \$\begingroup\$ Two bullets: 1. IRFZ44N isn't a suitable MOSFET, look for a MOSFET with TTL level. 2. If you have to use IRFZ44N Phillips datasheet shows it can be driven with VGS 6 Volt but poorly. \$\endgroup\$ – MatsK Aug 5 '17 at 18:28

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