The Problem: SMPS Output Noise

Switched-Mode Power Supplies (SMPS) are efficient, but they often produce output noise—tiny voltage ripples and spikes. These can interfere with sensors, microcontrollers, and audio circuits, leading to unreliable performance.

The Solution: Output Filtering

To suppress noise, you can add LC filters, ceramic capacitors, or ferrite beads at the SMPS output. A typical LC filter uses an inductor in series and a capacitor to ground to smooth out high-frequency noise.

Practical Example: Powering a Microcontroller

Let’s say you’re using a 5V SMPS to power an Arduino. Without filtering, the ripple can cause ADC errors or reset issues. Adding a 10µH inductor and a 100µF capacitor at the output can dramatically improve stability.

Sample Calculation: LC Filter Cutoff

To reduce noise above 10kHz:

L = 10µH, C = 100µF

Cutoff frequency:

f = 1 / (2π√(LC)) ≈ 1.6 kHz

This means most noise above this frequency is filtered out.

Product Suggestion: Made in India Components

• Ferrite Bead

• Capacitor Kit

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