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In my case i am using the shematics in a truck, i have the ground everywere on the truck body. I would like to control a led strip using mosfet (N or P) as a pwm switch on VCC (transistor beetween battery +12 and led's + wire).

Is it possible ?

Edit I have tried the solutions 1 and 2 of the possible duplicate link without success, any idear why and how to fix this ? My pwm command signal comes from an arduino 5V.

arduino mosfet

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  • \$\begingroup\$ Yes. Use P channel. When gate is high, FET is OFF. When gate is low, FET is on. If your PWM output does not go up all the way to +12, you may want to pull up the MOSFET gate to 12V, and use an NPN BJT to drive the MOSFET gate (that will allow you to use positive PWM, also, since the BJT inverts). Also, you may want to read this: w8ji.com/negative_lead_to_battery.htm \$\endgroup\$ – mkeith Feb 7 '15 at 21:08
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LED strip can be controlled using either. I suggest N-channel low side switch for its being cheaper at higher capacities.

You can, with proper electricial insulation (e.g. silk pad), screw the power MOSFET to the metal parts of your truck and run the MOSFET at near full load though :)

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  • \$\begingroup\$ If the OP uses an N-Channel FET in the high side he'll have to come up with a way to bring the gate above 12V to turn it on. Likely between 5-10V above the 12V rail. A P-FET could be used in the high side and the gate brought to ground to turn it on. (Assuming the gate is 12V tolerant.) Since this is an automotive application though the OP may wish to research load dump and automotive transients and provide protection against those types of things. \$\endgroup\$ – John D Feb 7 '15 at 21:02

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