5
\$\begingroup\$

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

enter image description here

\$\endgroup\$

1 Answer 1

10
\$\begingroup\$

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.

\$\endgroup\$
2
  • \$\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

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.