When switching high-speed MOSFETs in your circuits, especially for motor control, SMPS, or LED dimmers, you may notice unexpected noise, glitches, or even EMI issues. This is often due to switching transients and ringing—but it’s fixable!

The Problem: High-Frequency Switching Noise

MOSFETs switch fast—sometimes too fast. This causes voltage spikes and ringing due to parasitic inductance and capacitance in the layout. These issues can:

• Corrupt sensor readings

• Interfere with wireless modules

• Damage components over time

The Solution: RC Snubber or Gate Resistor Filters

To reduce this noise:

• Add a small gate resistor (10–100Ω) to slow down the switching speed

• Use an RC snubber (e.g., 100Ω + 100nF) across the MOSFET’s drain-source or drain-gate to absorb high-frequency oscillations

Practical Example: Motor Driver Circuit

You’re using an N-channel MOSFET to switch a 12V DC motor. You notice your ESP32 resets when switching on the motor.

Fix: Add a 47Ω gate resistor and a 100nF + 100Ω snubber. This smoothens switching edges and eliminates noise spikes.

Sample Calculation: Gate Resistor

For a 10nC gate charge and 47Ω resistor:

Turn-on delay ≈ Q / V = 10nC / (5V / 47Ω) = ~94ns – fast but damped.

Product Suggestion (Made in India)

Clean your builds with Made in India tools:

• MOSFETs – Choose from N/P-channel power types

• Flux Paste – For secure, low-resistance soldering

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