Mosfet Gate Current Limiting Resistor. Critically damped external gate resistor rgate 7 ω. However if you re using the mosfet as a linear amplifier instead of a switch there are certain amplifier topologies that can be marginally stable or even unstable with some mosfets in some physical packages and the easy fix is a gate stopper resistor in series with the gate.
You have connected a 22ohm resistor between the gate of the mosfet and the pic port pin this is a very low resistor and you will definitely have a voltage drop in the pic output the output voltage drops below 5v when you pull current and your resistor is limiting the gate current to more than 200ma and this is far more than the 25ma that pic can give. You can see the effect of the gate current limitation on the rise and fall times as well as the delay. The magenta signal is the drive signal seen before the series resistor.
If you look at the mosfet power dissipation you will also see that it increases from 28w to 105w with the gate resistor.
You can see the effect of the gate current limitation on the rise and fall times as well as the delay. Sometimes a gate resistor is prudent to reduce ringing especially if the trace driving the gate is long or if you are concerned with generating electromagnetic interference. You have connected a 22ohm resistor between the gate of the mosfet and the pic port pin this is a very low resistor and you will definitely have a voltage drop in the pic output the output voltage drops below 5v when you pull current and your resistor is limiting the gate current to more than 200ma and this is far more than the 25ma that pic can give. The main purpose of a series gate resistor on a mosfet is to limit the current peaks the arduino output pin has to supply to the gate.
