What is the aim of 100ohm resistor between the micro-controller pin and the gate of the N-channel MOSFET?

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1 Answer 1


The 100 Ohm resistor on the gate of the N-Channel MOSFET is there to stop any potential ringing. Ringing is caused by gate capacitance in series with the inductance of the track/wire.

The 10k resistor is just a pull-up resistor to keep the gate of the P-Channel MOSFET high. Or so I assume as you haven't actually labelled the nodes of the P-Channel. Once the MCU pin goes high, the N-Channel MOSFET turns on, which pulls the gate of the P-Channel MOSFET low, turning it on and allowing current to flow through it.

  • \$\begingroup\$ Is it worth explaining the finite turn-off time as a function of the pull-up value? \$\endgroup\$
    – AaronD
    Dec 30, 2020 at 20:40
  • \$\begingroup\$ @AaronD I'd say not. Looking at the nature of the question, it's clearly a beginner level question. So they deserve answers that don't overcomplicate things in my opinion. It's likely not going to be of much use at this level \$\endgroup\$
    – MCG
    Jan 1, 2021 at 22:20

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