The Problem: Noisy SMPS Circuits Can Wreck Your Project

Switch Mode Power Supplies (SMPS) are efficient, but they often generate high-frequency noise that interferes with sensitive electronics like sensors, audio circuits, or RF modules. This noise can cause erratic readings, buzzing speakers, or Wi-Fi drops—especially in compact DIY or smart home setups.

The Solution: Filter, Shield, and Route Properly

To reduce SMPS noise, use ferrite beads, low ESR capacitors, and proper PCB layout. Place ceramic capacitors (0.1µF + 10µF) close to the load, and use shielded inductors. Also, ground routing and loop area minimization are key for beginners aiming for clean power lines.

Practical Example: Fixing Wi-Fi Dropouts in a DIY Smart Plug

A prototyper in Mumbai built a smart plug using an ESP8266 and a compact SMPS module. The Wi-Fi kept disconnecting. He added a 10µH inductor with a 100µF capacitor at the SMPS output. Noise dropped drastically, and the system ran smoothly.

Sample Calculation: LC Filter Cutoff Frequency

To filter 100kHz switching noise:

L = 10µH, C = 100µF

f = 1 / (2π√(LC)) = ~1.6kHz

Perfect to suppress high-frequency ripple!

Product Suggestion: Choose Quality Made in India Inductors & Capacitors

Use low ESR capacitors and shielded inductors built in India for cleaner, stable designs.

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