Mosfet -pmw to gate resistor

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lax123

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Mosfet -pmw to gate resistor

« on: February 13, 2013, 03:10:03 pm »

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Hi,

i want to controll an RGB Ledstrip via ardu pwm.

Is the following true:
-you dont need a resistor (like 100 Ohms) between gate and ardu output.
-you dont need a resistor of like 100k from gate to gnd.

Could you help me with these questions please?


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CrossRoads

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Re: Mosfet -pmw to gate resistor

« Reply #1 on: February 13, 2013, 03:23:15 pm »

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-you dont need a resistor (like 100 Ohms) between gate and ardu output. FALSE. This limits the current flow into the MOSFET gate capacitance and prevents arduino pin damage. I'd recommend 150, 180 ohm
5V/150ohm = 33mA

-you dont need a resistor of like 100k from gate to gnd. Up to you - if you don't care about the gate floating while the arduino starts and eventually controlling the pin, you can leave it off. Otherwise, add it so your N-channel MOSFET is off while the arduino starts up.


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